Subjects -> METEOROLOGY (Total: 106 journals)
 Showing 1 - 36 of 36 Journals sorted alphabetically Acta Meteorologica Sinica       (Followers: 4) Advances in Atmospheric Sciences       (Followers: 45) Advances in Climate Change Research       (Followers: 50) Advances in Meteorology       (Followers: 27) Advances in Statistical Climatology, Meteorology and Oceanography       (Followers: 11) Aeolian Research       (Followers: 7) Agricultural and Forest Meteorology       (Followers: 20) American Journal of Climate Change       (Followers: 37) Atmósfera       (Followers: 2) Atmosphere       (Followers: 33) Atmosphere-Ocean       (Followers: 16) Atmospheric and Oceanic Science Letters       (Followers: 13) Atmospheric Chemistry and Physics (ACP)       (Followers: 43) Atmospheric Chemistry and Physics Discussions (ACPD)       (Followers: 15) Atmospheric Environment       (Followers: 72) Atmospheric Environment : X       (Followers: 3) Atmospheric Research       (Followers: 73) Atmospheric Science Letters       (Followers: 40) Boundary-Layer Meteorology       (Followers: 32) Bulletin of Atmospheric Science and Technology       (Followers: 5) Bulletin of the American Meteorological Society       (Followers: 63) Carbon Balance and Management       (Followers: 6) Ciencia, Ambiente y Clima       (Followers: 1) Climate       (Followers: 8) Climate and Energy       (Followers: 6) Climate Change Economics       (Followers: 44) Climate Change Responses       (Followers: 23) Climate Dynamics       (Followers: 45) Climate Law       (Followers: 6) Climate of the Past (CP)       (Followers: 6) Climate of the Past Discussions (CPD)       (Followers: 1) Climate Policy       (Followers: 51) Climate Research       (Followers: 9) Climate Resilience and Sustainability       (Followers: 21) Climate Risk Management       (Followers: 10) Climate Services       (Followers: 4) Climatic Change       (Followers: 69) Current Climate Change Reports       (Followers: 17) Dynamics and Statistics of the Climate System       (Followers: 6) Dynamics of Atmospheres and Oceans       (Followers: 19) Earth Perspectives - 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Similar Journals
 Monthly Notices of the Royal Astronomical SocietyJournal Prestige (SJR): 2.346 Citation Impact (citeScore): 4Number of Followers: 13      Hybrid journal (It can contain Open Access articles) ISSN (Print) 0035-8711 - ISSN (Online) 1365-2966 Published by Oxford University Press  [419 journals]
• Thermal and non-thermal X-ray emission from the rotation-powered

Authors: Rigoselli M; Mereghetti S, Anzuinelli S, et al.
Pages: 3113 - 3121
Abstract: ABSTRACTWe report the results of new XMM-Newton observations of the middle-aged (τc = 1.1 × 105 yr) radio pulsar PSR J1740+1000 carried out in 2017–2018. These long pointings (∼530 ks) show that the non-thermal emission, well described by a power-law spectrum with photon index Γ = 1.80 ± 0.17, is pulsed with a ∼30 per cent pulsed fraction above 2 keV. The thermal emission can be well-fit with the sum of two blackbodies of temperatures kT1 = 70 ± 4 eV and kT2 = 137 ± 7 eV, and emitting radii $R_1=5.4_{-0.9}^{+1.3}$ km and $R_2=0.70_{-0.13}^{+0.15}$ km (for a distance of 1.2 kpc). We found no evidence for absorption lines as those observed in the shorter XMM-Newton observations (∼67 ks) of this pulsar carried out in 2006. The X-ray thermal and non-thermal components peak in antiphase and none of them is seen to coincide in phase with the radio pulse. This, coupled with the small difference in the emission radii of the two thermal components, disfavours an interpretation in which the dipolar polar cap is heated by magnetospheric backward-accelerated particles. Comparison with the other thermally emitting isolated neutron stars with spectra well described by the sum of two components at different temperatures shows that the ratios T2/T1 and R2/R1 are similar for objects of different classes. The observed values cannot be reproduced with simple temperature distributions, such as those caused by a dipolar field, indicating the presence of more complicated thermal maps.
PubDate: Wed, 27 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1130
Issue No: Vol. 513, No. 3 (2022)

• The ALMA REBELS Survey: cosmic dust temperature evolution out to z ∼
7

Authors: Sommovigo L; Ferrara A, Pallottini A, et al.
Pages: 3122 - 3135
Abstract: ABSTRACTALMA observations have revealed the presence of dust in the first generations of galaxies in the Universe. However, the dust temperature Td remains mostly unconstrained due to the few available FIR continuum data at redshift $z$ > 5. This introduces large uncertainties in several properties of high-$z$ galaxies, namely their dust masses, infrared luminosities, and obscured fraction of star formation. Using a new method based on simultaneous [C $\scriptstyle \rm II$] 158-μm line and underlying dust continuum measurements, we derive Td in the continuum and [C $\scriptstyle \rm II$] detected $z$ ≈ 7 galaxies in the ALMA Large Project REBELS sample. We find 39 < Td < 58 K, and dust masses in the narrow range Md = (0.9−3.6) × 107 M⊙. These results allow us to extend for the first time the reported Td($z$) relation into the Epoch of Reionization. We produce a new physical model that explains the increasing Td($z$) trend with the decrease of gas depletion time, tdep = Mg/SFR, induced by the higher cosmological accretion rate at early times; this hypothesis yields Td ∝ (1 + $z$)0.4. The model also explains the observed Td scatter at a fixed redshift. We find that dust is warmer in obscured sources, as a larger obscuration results in more efficient dust heating. For UV-transparent (obscured) galaxies, Td only depends on the gas column density (metallicity), $T_{\rm d} \propto N_{\rm H}^{1/6}$ (Td ∝ Z−1/6). REBELS galaxies are on average relatively transparent, with effective gas column densities around NH ≃ (0.03−1) × 1021 cm−2. We predict that other high-$z$ galaxies (e.g. MACS0416-Y1, A2744-YD4), with estimated Td ≫ 60 K, are significantly obscured, low-metallicity systems. In fact, Td is higher in metal-poor systems due to their smaller dust content, which for fixed LIR results in warmer temperatures.
PubDate: Thu, 03 Feb 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac302
Issue No: Vol. 513, No. 3 (2022)

• A search for stellar structures around nine outer halo globular clusters
in the Milky Way

Authors: Zhang S; Mackey D, Da Costa G.
Pages: 3136 - 3164
Abstract: ABSTRACTWe use deep imaging from the Dark Energy Camera to explore the peripheral regions of nine globular clusters in the outer halo of the Milky Way. Apart from Whiting 1 and NGC 7492, which are projected against the Sagittarius stream, we see no evidence for adjacent stellar populations to indicate any of these clusters is associated with coherent tidal debris from a destroyed host dwarf. We also find no evidence for tidal tails around any of the clusters in our sample; however, both NGC 1904 and 6981 appear to possess outer envelopes. Motivated by a slew of recent Gaia-based discoveries, we compile a sample of clusters with robust detections of extra-tidal structure, and search for correlations with orbital properties. While we observe that clusters with tidal tails are typically on moderately or very eccentric orbits that are highly inclined to the Galactic plane and often retrograde, these are neither necessary nor sufficient conditions for the formation of extra-tidal structure. That many objects with tidal tails appear to be accreted leads us to speculate that this lack of consistency may stem from the inhomogeneous dynamical history of the Milky Way globular cluster system. Finally, we note that clusters with prominent stellar envelopes detected in ground-based imaging (such as NGC 1851 and 7089) are now all known from Gaia to possess long tidal tails – experimental confirmation that the presence of an extended envelope is indicative of tidal erosion.
PubDate: Mon, 21 Mar 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac751
Issue No: Vol. 513, No. 3 (2022)

• MOMO – V. Effelsberg, Swift, and Fermi study of the blazar and
supermassive binary black hole candidate OJ 287 in a period of high
activity

Authors: Komossa S; Grupe D, Kraus A, et al.
Pages: 3165 - 3179
Abstract: ABSTRACTWe report results from our ongoing project MOMO (Multiwavelength Observations and Modelling of OJ 287). In this latest publication of a sequence, we combine our Swift UVOT–XRT and Effelsberg radio data (2.6–44 GHz) between 2019 and 2022.04 with public SMA data and gamma-ray data from the Fermi satellite. The observational epoch covers OJ 287 in a high state of activity from radio to X-rays. The epoch also covers two major events predicted by the binary supermassive black hole (SMBH) model of OJ 287. Spectral and timing analyses clearly establish: a new UV–optical minimum state in 2021 December at an epoch where the secondary SMBH is predicted to cross the disc surrounding the primary SMBH; an overall low level of gamma-ray activity in comparison to pre-2017 epochs; the presence of a remarkable, long-lasting UV–optical flare event of intermediate amplitude in 2020–2021; a high level of activity in the radio band with multiple flares; and particularly a bright, ongoing radio flare peaking in 2021 November that may be associated with a gamma-ray flare, the strongest in 6 yr. Several explanations for the UV–optical minimum state are explored, including the possibility that a secondary SMBH launches a temporary jet, but the observations are best explained by variability associated with the main jet.
PubDate: Thu, 24 Mar 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac792
Issue No: Vol. 513, No. 3 (2022)

• Single-dish 1-cm-band radio photometry of protoplanetary discs: few
centimetre-sized dust grains'

Authors: Greaves J; Mason B.
Pages: 3180 - 3190
Abstract: ABSTRACTRadio-wavelength observations of protoplanetary discs can show whether large dust grains (pebbles) have formed on the pathway to aggregation of planetary cores. The 100-m Green Bank Telescope was used to make a four-subband (26–40 GHz) photometric survey of the Taurus and Ophiuchus regions, which is nearly complete for class II systems above fixed millimetre-flux thresholds. There is evidence of anomalous microwave emission in 40 per cent of the systems, indicating that radio observations of protoplanetary discs need good spectral coverage to distinguish the presence of dust. At most, one-quarter of the systems are seen to host pebbles, of radii as large as 1 cm. The lack of pebble-dominated systems suggests that this is a short-lived phase in particle size evolution, and/or that pebbles only grow in limited areas of the disc. Either case supports models where grains of centimetre size rapidly fragment and/or drift towards the star, potentially feeding growing planets. In the best-fitting systems, including the 26–40 GHz data raises the detected dust mass by up to an order of magnitude, and the mass distribution of the discs may be flatter. Both of these phenomena could help to solve the ‘missing mass’ problem, where the solid budget in protoplanetary discs is compared with the substantial requirements of extrasolar-planet systems.
PubDate: Wed, 30 Mar 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac856
Issue No: Vol. 513, No. 3 (2022)

• High-mass pulsators in eclipsing binaries observed using TESS

Authors: Southworth J; Bowman D.
Pages: 3191 - 3209
Abstract: ABSTRACTPulsations and binarity are both common features of massive stars. The study of pulsating massive stars in eclipsing binary systems holds great potential for constraining stellar structure and evolution theory. However, prior to the all-sky Transiting Exoplanet Survey Satellite (TESS) mission, few such systems had been discovered or studied in detail. We have inspected the TESS light curves of a large number of eclipsing binaries known to contain high-mass stars, and compiled a list of 18 objects which show intrinsic variability. The light curves were modelled both to determine the physical properties of the systems, and to remove the effects of binarity in order to leave residual light curves suitable for asteroseismic analysis. Precise mass and radius measurements were obtained for δ Cir, CC Cas, SZ Cam V436 Per and V539 Ara. We searched the residual light curves for pulsation signatures and, within our sample of 18 objects, we find six definite and eight possible cases of β Cephei pulsation, seven cases of stochastic low-frequency (SLF) variability, and eight instances of possible slowly pulsating B (SPB) star pulsation. The large number of pulsating eclipsing systems we have identified makes asteroseismology of high-mass stars in eclipsing binaries a feasible avenue to constrain the interior physics of a large sample of massive stars for the first time.
PubDate: Tue, 05 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac875
Issue No: Vol. 513, No. 3 (2022)

• Cool circumgalactic gas in galaxy clusters: connecting the DESI legacy
imaging survey and SDSS DR16 Mg ii absorbers

Authors: Anand A; Kauffmann G, Nelson D.
Pages: 3210 - 3227
Abstract: ABSTRACTWe investigate the cool gas absorption in galaxy clusters by cross-correlating Mg ii absorbers detected in quasar spectra from data release 16 of the Sloan Digital Sky Survey (SDSS) with galaxy clusters identified in the Dark Energy Spectroscopic Instrument (DESI) survey. We find significant covering fractions ($1\!-\!5\, \mathrm{per\,cent}$ within r500, depending on the chosen redshift interval), ∼4–5 times higher than around random sightlines. While the covering fraction of cool gas in clusters decreases with increasing mass of the central galaxy, the total Mg ii mass within r500 is none the less ∼10 times higher than for SDSS luminous red galaxies. The Mg ii covering fraction versus impact parameter is well described by a power law in the inner regions and an exponential function at larger distances. The characteristic scale of the transition between these two regimes is smaller for large equivalent width absorbers. Cross-correlating Mg ii absorption with photo−$z$ selected cluster member galaxies from DESI reveals a statistically significant connection. The median projected distance between Mg ii absorbers and the nearest cluster member is ∼200 kpc, compared to ∼500 kpc in random mocks with the same galaxy density profiles. We do not find a correlation between Mg ii strength and the star formation rate of the closest cluster neighbour. This suggests that cool gas in clusters, as traced by Mg ii absorption, is: (i) associated with satellite galaxies, (ii) dominated by cold gas clouds in the intracluster medium, rather than by the interstellar medium of galaxies, and (iii) may originate in part from gas stripped from these cluster satellites in the past.
PubDate: Tue, 19 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac928
Issue No: Vol. 513, No. 3 (2022)

• Intermediate- and high-velocity clouds in the Milky Way – I. Covering
factors and vertical heights

Authors: Lehner N; Howk J, Marasco A, et al.
Pages: 3228 - 3240
Abstract: ABSTRACTIntermediate- and high-velocity clouds (IVCs, HVCs) are a potential source of fuel for star formation in the Milky Way (MW), but their origins and fates depend sensitively on their distances. We search for IVCs and HVCs in HST high-resolution ultraviolet spectra of 55 halo stars at vertical heights $z \gtrsim \,1$ kpc. We show that IVCs (40 ≤ $v$LSR < 90 ${\rm km\, s}^{-1}$) have a high detection rate – the covering factor, fc – that is about constant (fc = 0.90 ± 0.04) from $z$ = 1.5 to 14 kpc, implying IVCs are essentially confined to $z$ ≲ 1.5 kpc. For the HVCs (90 ≤ $v$LSR ≲ 170 ${\rm km\, s}^{-1}$), we find fc increases from fc ≃ 0.14 ± 0.10 at $z$ ≲ 2–3 kpc to fc = 0.60 ± 0.15 at 6 ≲ $z$ ≲ 14 kpc, the latter being similar to that found towards QSOs. In contrast, the covering factor of very high-velocity clouds (VHVCs; $v$LSR ≳ 170 ${\rm km\, s}^{-1}$) is $f_c \lt 0.04$ in the stellar sample compared to 20 per cent towards QSOs, implying these clouds must be at d ≳ 10–15 kpc ( $z$ ≳ 10 kpc). Gas clouds with $v$LSR > 40 ${\rm km\, s}^{-1}$ at b ≳ 15° have therefore $v$LSR decreasing with decreasing $z$ . Our findings are consistent with a Galactic rain and/or fountain origin for these clouds. In the latter scenario, VHVCs may mostly serve as fuel for the MW halo. In view of their high covering factors and since all the IVCs and some HVCs are found in the thick disc, they appear good candidates as gas reservoirs to help sustain star formation in the MW.
PubDate: Sat, 09 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac987
Issue No: Vol. 513, No. 3 (2022)

• Correction to: Outflows from starburst galaxies with various driving
mechanisms and their X-ray properties

Pages: 3241 - 3241
Abstract: This is a correction to: B. P. Brian Yu, Ellis R. Owen, Kuo-Chuan Pan, Kinwah Wu, Ignacio Ferreras, Outflows from starburst galaxies with various driving mechanisms and their X-ray properties, Monthly Notices of the Royal Astronomical Society, Volume 508, Issue 4, December 2021, Pages 5092–5113, https://doi.org/10.1093/mnras/stab2738. In the originally published version of this manuscript, fig. 8 printed out incorrectly. This error has been corrected (online).
PubDate: Tue, 10 May 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1085
Issue No: Vol. 513, No. 3 (2022)

• Asteroid phase curves using sparse Gaia DR2 data and differential dense
light curves

Authors: Wilawer E; Oszkiewicz D, Kryszczyńska A, et al.
Pages: 3242 - 3251
Abstract: ABSTRACTThe amount of sparse asteroid photometry being gathered by both space- and ground-based surveys is growing exponentially. This large volume of data poses a computational challenge owing to both the large amount of information to be processed and the new methods needed to combine data from different sources (e.g. obtained by different techniques, in different bands, and having different random and systematic errors). The main goal of this work is to develop an algorithm capable of merging sparse and dense data sets, both relative and differential, in preparation for asteroid observations originating from, for example, Gaia, TESS, ATLAS, LSST, K2, VISTA, and many other sources. We present a novel method to obtain asteroid phase curves by combining sparse photometry and differential ground-based photometry. In the traditional approach, the latter cannot be used for phase curves. Merging those two data types allows for the extraction of phase-curve information for a growing number of objects. Our method is validated for 26 sample asteroids observed by the Gaia mission.
PubDate: Wed, 11 May 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1008
Issue No: Vol. 513, No. 3 (2022)

• A systematic search for galaxy protocluster cores at the transition epoch
of their star formation activity

Authors: Ando M; Shimasaku K, Momose R, et al.
Pages: 3252 - 3272
Abstract: ABSTRACTThe redshift of z ∼ 1.5 is the transition epoch of protoclusters (PCs) from the star-forming phase into the quenching phase, and hence an appropriate era to investigate the build up of the quenched population. We define a ‘core’ as the most massive halo in a given PC, where environmental effects are likely to work most effectively, and search for cores at 1 < z < 1.5. We use a photometric redshift catalogue of a wide (effective area of ${\sim}22.2\, \mathrm{deg}^{2}$) and deep ($i\sim 26.8\, \mathrm{mag}$) optical survey with Subaru Hyper-Suprime Cam. Regarding galaxies with log (M*/M⊙) > 11.3 as the central galaxies of PC cores, we estimate their average halo mass by clustering analysis and find it to be log (Mh/M⊙) ∼ 13.7. An expected mass growth by the IllustrisTNG simulation and the observed overdensities around them suggest that the PC cores we find are progenitors of present-day clusters. Classifying our galaxy sample into red and blue galaxies, we calculate the stellar mass function (SMF) and the red galaxy fraction. The SMFs in the PC cores are more-top heavy than field, implying early high-mass galaxy formation and disruption of low-mass galaxies. We also find that the red fraction increases with stellar mass, consistent with stellar mass dependent environmental quenching recently found at z > 1. Interestingly, although the cores with red and blue centrals have similar halo masses, only those with red centrals show a significant red fraction excess compared to the field, suggesting a conformity effect. Some observational features of PC cores may imply that the conformity is caused by assembly bias.
PubDate: Fri, 15 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1049
Issue No: Vol. 513, No. 3 (2022)

• The contribution of non-central radio galaxies to AGN feedback in rich
galaxy clusters

Authors: Seth R; O’Sullivan E, Sebastian B, et al.
Pages: 3273 - 3288
Abstract: ABSTRACTWe present a combined radio/X-ray study of six massive galaxy clusters, aimed at determining the potential for heating of the intra-cluster medium (ICM) by non-central radio galaxies. Since X-ray cavities associated with the radio lobes of non-central galaxies are generally not detectable, we use Giant Metrewave Radio Telescope 610 MHz observations to identify jet sources and estimate their size, and Chandra data to estimate the pressure of the surrounding ICM. In the radio, we detect 4.5 per cent of galaxies above the spectroscopic survey limit (M$^{*}_{K}$ + 2.0) of the Arizona cluster redshift survey (ACReS) that covers five of our six clusters. Approximately one-tenth of these are extended radio sources. Using star formation (SF) rates determined from mid-infrared data, we estimate the expected contribution to radio luminosity from the stellar population of each galaxy, and find that most of the unresolved or poorly resolved radio sources are likely SF dominated. The relatively low frequency and good spatial resolution of our radio data allows us to trace SF emission down to galaxies of stellar mass ∼10 9.5 M⊙. We estimate the enthalpy of the (AGN-dominated) jet/lobe and tailed sources, and place limits on the energy available from unresolved radio jets. We find jet powers in the range ∼1043 to 1046 erg s−1, comparable to those of brightest cluster galaxies. Our results suggest that while cluster-central sources are the dominant factor balancing ICM cooling over the long-term, non-central sources may have a significant impact, and that further investigation is possible and warranted.
PubDate: Mon, 18 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1064
Issue No: Vol. 513, No. 3 (2022)

• On the potential of faraday tomography to identify shock structures in
supernova remnants

Authors: Ideguchi S; Inoue T, Akahori T, et al.
Pages: 3289 - 3301
Abstract: ABSTRACTKnowledge about the magnetic fields in supernova remnants (SNRs) is of paramount importance for constraining Galactic cosmic ray acceleration models. It could also indirectly provide information on the interstellar magnetic fields. In this paper, we predict the Faraday dispersion functions (FDFs) of SNRs for the first time. For this study, we use the results of three dimensional (3D) ideal magnetohydrodynamic (MHD) simulations of SNRs expanding into a weak, regular magnetic field. We present the intrinsic FDFs of the shocked region of SNRs for different viewing angles. We find that the FDFs are generally Faraday complex, which implies that conventional rotation measure study is not sufficient to obtain the information on the magnetic fields in the shocked region and Faraday tomography is necessary. We also show that the FDF allows to derive the physical-depth distribution of polarization intensity when the line of sight is parallel to the initial magnetic field orientation. Furthermore, we demonstrate that the location of contact discontinuity can be identified from the radial profile of the width of the FDF with the accuracy of 0.1–0.2 pc.
PubDate: Fri, 22 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1086
Issue No: Vol. 513, No. 3 (2022)

• Dynamics of Colombo’s Top: non-trivial oblique spin equilibria of
super-Earths in multiplanetary systems

Authors: Su Y; Lai D.
Pages: 3302 - 3316
Abstract: ABSTRACTMany Sun-like stars are observed to host close-in super-Earths (SEs) as part of a multiplanetary system. In such a system, the spin of the SE evolves due to spin–orbit resonances and tidal dissipation. In the absence of tides, the planet’s obliquity can evolve chaotically to large values. However, for close-in SEs, tidal dissipation is significant and suppresses the chaos, instead driving the spin into various steady states. We find that the attracting steady states of the SE’s spin are more numerous than previously thought, due to the discovery of a new class of ‘mixed-mode’ high-obliquity equilibria. These new equilibria arise due to subharmonic responses of the parametrically driven planetary spin, an unusual phenomenon that arises in non-linear systems. Many SEs should therefore have significant obliquities, with potentially large impacts on the physical conditions of their surfaces and atmospheres.
PubDate: Tue, 26 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1096
Issue No: Vol. 513, No. 3 (2022)

• 3D mapping of the Wolf–Rayet nebula M 1-67: clues for post-common
envelope evolution in massive stars

Authors: Zavala S; Toalá J, Santamaría E, et al.
Pages: 3317 - 3325
Abstract: ABSTRACTWe present a 3D mapping of the Wolf–Rayet (WR) nebula M 1-67 around WR 124. We obtained high-resolution San Pedro Mártir (SPM) Manchester Echelle Spectrograph (MES) observations along 17 long-slit positions covering all morphological features in M 1-67. We are able to unveil the true morphology of M 1-67 and its kinematics by interpreting the SPM MES observations by means of the 3D modelling tool for Astrophysics shape. Our shape model that best reproduces the SPM MES data includes three concentric bipolar structures composed by a hollow ellipsoidal structure and a torus. In addition, the model requires the presence of expanding jets and broken blisters in order to reproduce specific spectral features. Our results are consistent with the idea that M 1-67 and its progenitor star WR 124 have formed through a common envelope scenario that occurred 11.8$^{+4.6}_{-0.8}$ kyr ago. Our bipolar model strongly questions previous suggestions of the presence of a bow shock structure surrounding M 1-67. We interpret that the bright structures detected in the spectra extracted from the central regions are produced by wind compression at the receding region of the innermost structure in M 1-67. Furthermore, WR 124 is moving through a low-density region above the Galactic plane that has negligibly affected the formation history of M 1-67.
PubDate: Tue, 26 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1097
Issue No: Vol. 513, No. 3 (2022)

• Towards convergence of turbulent dynamo amplification in cosmological
simulations of galaxies

Authors: Martin-Alvarez S; Devriendt J, Slyz A, et al.
Pages: 3326 - 3344
Abstract: ABSTRACTOur understanding of the process through which magnetic fields reached their observed strengths in present-day galaxies remains incomplete. One of the advocated solutions is a turbulent dynamo mechanism that rapidly amplifies weak magnetic field seeds to the order of ∼$\mu$G. However, simulating the turbulent dynamo is a very challenging computational task due to the demanding span of spatial scales and the complexity of the required numerical methods. In particular, turbulent velocity and magnetic fields are extremely sensitive to the spatial discretization of simulated domains. To explore how refinement schemes affect galactic turbulence and amplification of magnetic fields in cosmological simulations, we compare two refinement strategies. A traditional quasi-Lagrangian adaptive mesh refinement approach focusing spatial resolution on dense regions, and a new refinement method that resolves the entire galaxy with a high resolution quasi-uniform grid. Our new refinement strategy yields much faster magnetic energy amplification than the quasi-Lagrangian method, which is also significantly greater than the adiabatic compressional estimate indicating that the extra amplification is produced through stretching of magnetic field lines. Furthermore, with our new refinement the magnetic energy growth factor scales with resolution following $\propto {\Delta x}_\text{max}^{-1/2}$, in much better agreement with small-scale turbulent box simulations. Finally, we find evidence suggesting most magnetic amplification in our simulated galaxies occurs in the warm phase of their interstellar medium, which has a better developed turbulent field with our new refinement strategy.
PubDate: Mon, 25 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1099
Issue No: Vol. 513, No. 3 (2022)

• Shocking interactions of supernova remnants with atomic and molecular
clouds – the interplay between shocks, thermal instability, and gravity
in the large cloud regime

Authors: Kupilas M; Pittard J, Wareing C, et al.
Pages: 3345 - 3358
Abstract: ABSTRACTUsing the adaptive mesh refinement code mg, we perform 3D hydrodynamic simulations of a supernova–cloud interaction in the ‘large cloud regime’. The cloud is initially atomic and evolving due to the thermal instability (TI) and gravity. We study interactions in a ‘pre-TI’ and ‘post-TI’ stage when cold and dense clumps are present, and compare these results to idealized shock–cloud scenarios in the ‘small cloud regime’, and a scenario without shocks. On aggregate, the supernova disruption is significantly weaker than that from an idealized shock due to the supernova impact being instantaneous, and not continuous. In both supernova–cloud interactions, we observe two shocks impact the cloud, followed by the development of a weak 10 km s−1 upstream flow on the cloud interface, and a global ambient pressure drop. When the cloud is still atomic, it expands due to this drop. Additionally, the TI is triggered at the front of the cloud, causing the formation of a cap-like structure with clumps embedded inside. The upstream flow converges in this region, resulting in a lobe-like cloud morphology. When the cloud is molecular, the transmitted shock disrupts the inter-clump material and causes the clumps’ outer envelopes to expand slightly and form tail-like morphologies. These effects are less pronounced than those in our shock–cloud scenarios, and more pronounced that those in our un-shocked scenario. After ∼ 3.5 Myr, the effects from the supernova decay and the cloud returns to an almost indistinguishable state from an un-shocked cloud, in spite of the global ambient pressure drop. In neither supernova–cloud scenario do we see any local gravitational collapse.
PubDate: Sat, 30 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1104
Issue No: Vol. 513, No. 3 (2022)

• Evidence for neutron star triaxial free precession in Her X-1 from
Fermi/GBM pulse period measurements

Authors: Kolesnikov D; Shakura N, Postnov K.
Pages: 3359 - 3367
Abstract: ABSTRACTHer X-1/HZ Her is one of the best studied accreting X-ray pulsars. In addition to the pulsating and orbital periods, the X-ray and optical light curves of the source exhibit an almost periodic 35-d variability caused by a precessing accretion disc. The nature of the observed long-term stability of the 35-d cycle has been debatable. The X-ray pulse frequency of Her X-1 measured by the Fermi/GBM demonstrates periodical variations with X-ray flux at the main-on state of the source. We explain the observed periodic sub-microsecond pulse frequency changes by the free precession of a triaxial neutron star (NS) with parameters previously inferred from an independent analysis of the X-ray pulse evolution over the 35-d cycle. In the Fermi/GBM data, we identified several time intervals with a duration of half a year or longer where the NS precession period describing the pulse frequency variations does not change. We found that the NS precession period varies within one per cent in different intervals. Such variations in the free precession period on a year time-scale can be explained by $\lesssim 1{{\ \rm per\ cent}}$ changes in the fractional difference between the triaxial NS’s moments of inertia due to the accreted mass readjustment or variable internal coupling of the NS crust with the core.
PubDate: Wed, 27 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1107
Issue No: Vol. 513, No. 3 (2022)

• Revisiting the quasi-molecular mechanism of recombination

Authors: Huang Z.
Pages: 3368 - 3371
Abstract: ABSTRACTThe quasi-molecular mechanism of recombination (QMR), recently suggested by Kereselidze et al., is a non-standard process where an electron and two neighboring protons in the early Universe directly form an ionized hydrogen molecule in a highly excited state, which then descends to lower levels or dissociates. It has been suggested that the increased binding energy due to the participation of a second proton may lead to an earlier cosmic recombination that alleviates the Hubble tension. Revisiting the quasi-molecular channel of recombination in more details, we find that the original work significantly overestimated the probability of finding a pair of adjacent protons in the relevant epoch (z ∼ a few thousand). Our new estimation suggests that the QMR cannot be the primary cause of the Hubble tension.
PubDate: Mon, 25 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1127
Issue No: Vol. 513, No. 3 (2022)

• The role of linearly polarized transverse MHD waves in heating the solar
coronal plasma

Authors: Pandey V; Kumar A, Nayak M.
Pages: 3372 - 3386
Abstract: ABSTRACTWe derive a general dispersion relation for linearly polarized transverse magnetohydrodynamic (MHD) waves in an inhomogeneous, viscous, and resistive coronal plasma. We assume density structuring along the direction of polarization of the wave. In the linear regime and for an incompressible and homogeneous plasma, where the criterion of ignorable coordinates is satisfied, our solution corresponds to the customary Alfvén wave, which is basically dissipated by shear viscosity or resistivity. However, the assumption of density stratification along the direction of polarization of waves breaks down the criterion of ignorable coordinates, due to which transversal wave perturbations become compressible and, consequently, compressive viscosity turns out to be an important process. We find that for a typical coronal plasma with a magnetic field of 5 to 22 G, transverse body waves with a period of less than 10 s can dissipate energy on a time scale comparable to the coronal radiative time in their antisymmetric mode. Thus, it is possible that linearly polarized transverse wave perturbations dissipated by ion compressive viscosity maintain a hot coronal temperature.
PubDate: Wed, 11 May 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac817
Issue No: Vol. 513, No. 3 (2022)

• The scaling relation between galaxy luminosity and WHIM density from EAGLE
simulations with application to SDSS data

Authors: Holt P; Tuominen T, Nevalainen J, et al.
Pages: 3387 - 3398
Abstract: ABSTRACTThis paper presents an updated scaling relation between the optical luminosity density (LD) of galaxies in the r band and the density of the warm–hot intergalactic medium (WHIM) in cosmic filaments, using the high-resolution EAGLE simulations. We find a strong degree of correlation between the WHIM density and the galaxy luminosity density, resulting in a scaling relation between the two quantities that permits us to predict the WHIM density of filaments with a scatter of less than $\frac {1}{2}$ dex in a broad range of smoothed filament luminosity densities. In order to estimate the performance of the simulation-based calibration of the LD–WHIM density relation, we applied it to a sample of low-redshift filaments detected with the Bisous method in the Legacy Survey SDSS DR12 data. In the volume covered by the SDSS data, our relation predicts a WHIM density amounting to 31 ± 7 ± 12 per cent (statistical errors followed by systematic) of cosmic baryon density. This agrees, albeit within the large uncertainties, with the current estimates of the cosmological missing baryon fraction, implying that our LD–WHIM density relation may be a useful tool in the search for the missing baryons. This method of analysis provides a new promising avenue to study the physical properties of the missing baryons, using an observable that is available for large volumes of the sky, complementary and independent from WHIM searches with absorption-line systems in the FUV or X-rays.
PubDate: Wed, 30 Mar 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac866
Issue No: Vol. 513, No. 3 (2022)

• Dynamics of charged particles and quasi-periodic oscillations in the
vicinity of a distorted, deformed compact object embedded in a uniform
magnetic field

Authors: Faraji S; Trova A.
Pages: 3399 - 3413
Abstract: ABSTRACTThis work presents the dynamic properties of charged test particles influenced by the gravitational and electromagnetic fields. Accordingly in this work, we concentrate on the static and axially symmetric metric containing two quadrupole parameters. One relates to the central object, and another relates to the external distribution of matter. This metric may associate the observable effects to these parameters as dynamical degrees of freedom. The astrophysical motivation for choosing such a field is the possibility to constitute a reasonable model for an actual situation occurring in the objects’ vicinity. To test the role of large-scale magnetic fields in accretion processes, we start by analysing different time-like bound orbits under the influence of the system’s different parameters. This leads to examining their stability concerning radial and/or vertical oscillations. The main focus is to discuss the effect of magnetic field on the oscillation modes’ resonant phenomena using different resonant models for disc-oscillation modes. In the present contribution, we further explore the possibility of relating oscillatory frequencies of charged particles to the frequencies of the high-frequency quasi-periodic oscillations observed in the microquasars GRS 1915+105, XTE 1550-564, and GRO 1655-40 via assuming relevance of resonant phenomena on the radial and vertical oscillations.
PubDate: Fri, 01 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac882
Issue No: Vol. 513, No. 3 (2022)

• Where outflows meet inflows: gas kinematics in SSA22 Ly α blob 2 decoded

Authors: Li Z; Steidel C, Gronke M, et al.
Pages: 3414 - 3428
Abstract: ABSTRACTWe present new spectroscopic observations of Ly α (Ly α) Blob 2 (z ∼ 3.1). We observed extended Ly α emission in three distinct regions, where the highest Ly α surface brightness (SB) centre is far away from the known continuum sources. We searched through the MOSFIRE slits that cover the high Ly α SB regions, but were unable to detect any significant nebular emission near the highest SB centre. We further mapped the flux ratio of the blue peak to the red peak and found it is anticorrelated with Ly α SB with a power-law index of ∼ –0.4. We used radiative transfer models with both multiphase, clumpy, and shell geometries and successfully reproduced the diverse Ly α morphologies. We found that most spectra suggest outflow-dominated kinematics, while 4/15 spectra imply inflows. A significant correlation exists between parameter pairs, and the multiphase, clumpy model may alleviate previously reported discrepancies. We also modelled Ly α spectra at different positions simultaneously and found that the variation of the inferred clump outflow velocities can be approximately explained by line-of-sight projection effects. Our results support the ‘central powering  + scattering’ scenario, i.e. the Ly α photons are generated by a central powering source and then scatter with outflowing, multiphase H  i gas while propagating outwards. The infalling of cool gas near the blob outskirts shapes the observed blue-dominated Ly α profiles, but its energy contribution to the total Ly α luminosity is less than 10 per cent, i.e. minor compared to the photoionization by star-forming galaxies and/or AGNs.
PubDate: Fri, 08 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac958
Issue No: Vol. 513, No. 3 (2022)

• Is Terzan 5 the remnant of a building block of the Galactic
bulge' Evidence from APOGEE

Authors: Taylor D; Mason A, Schiavon R, et al.
Pages: 3429 - 3443
Abstract: ABSTRACTIt has been proposed that the globular cluster-like system Terzan 5 is the surviving remnant of a primordial building block of the Milky Way bulge, mainly due to the age/metallicity spread and the distribution of its stars in the α–Fe plane. We employ Sloan Digital Sky Survey data from the Apache Point Observatory Galactic Evolution Experiment to test this hypothesis. Adopting a random sampling technique, we contrast the abundances of 10 elements in Terzan 5 stars with those of their bulge field counterparts with comparable atmospheric parameters, finding that they differ at statistically significant levels. Abundances between the two groups differ by more than 1σ in Ca, Mn, C, O, and Al, and more than 2σ in Si and Mg. Terzan 5 stars have lower [α/Fe] and higher [Mn/Fe] than their bulge counterparts. Given those differences, we conclude that Terzan 5 is not the remnant of a major building block of the bulge. We also estimate the stellar mass of the Terzan 5 progenitor based on predictions by the Evolution and Assembly of GaLaxies and their Environments suite of cosmological numerical simulations, concluding that it may have been as low as ∼3 × 108 M⊙ so that it was likely unable to significantly influence the mean chemistry of the bulge/inner disc, which is significantly more massive (∼1010 M⊙). We briefly discuss existing scenarios for the nature of Terzan 5 and propose an observational test that may help elucidate its origin.
PubDate: Fri, 08 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac968
Issue No: Vol. 513, No. 3 (2022)

• Constraints on TESS albedos for five hot Jupiters

Authors: Blažek M; Kabáth P, Piette A, et al.
Pages: 3444 - 3457
Abstract: ABSTRACTPhotometric observations of occultations of transiting exoplanets can place important constraints on the thermal emission and albedos of their atmospheres. We analyse photometric measurements and derive geometric albedo (Ag) constraints for five hot Jupiters observed with TESS in the optical: WASP-18 b, WASP-36 b, WASP-43 b, WASP-50 b, and WASP-51 b. For WASP-43 b, our results are complemented by a VLT/HAWK-I observation in the near-infrared at $2.09\, \mu$m. We derive the first geometric albedo constraints for WASP-50 b and WASP-51 b: Ag < 0.445 and Ag < 0.368, respectively. We find that WASP-43 b and WASP-18 b are both consistent with low geometric albedos (Ag < 0.16) even though they lie at opposite ends of the hot Jupiter temperature range with equilibrium temperatures of ∼1400 K and ∼2500 K, respectively. We report self-consistent atmospheric models that explain broad-band observations for both planets from TESS, HST, Spitzer, and VLT/HAWK-I. We find that the data of both hot Jupiters can be explained by thermal emission alone and inefficient day–night energy redistribution. The data do not require optical scattering from clouds/hazes, consistent with the low geometric albedos observed.
PubDate: Sat, 09 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac992
Issue No: Vol. 513, No. 3 (2022)

• Degeneracies between self-interacting dark matter and supernova feedback
as cusp-core transformation mechanisms

Authors: Burger J; Zavala J, Sales L, et al.
Pages: 3458 - 3481
Abstract: ABSTRACTWe present a suite of 16 high-resolution hydrodynamic simulations of an isolated dwarf galaxy (gaseous and stellar disc plus a stellar bulge) within an initially cuspy dark matter (DM) halo, including self-interactions between the DM particles; as well as stochastic star formation and subsequent supernova feedback (SNF), implemented using the stellar feedback model SMUGGLE. The simulations start from identical initial conditions, and we regulate the strength of DM self-interactions and SNF by systematically varying the self-interacting DM (SIDM) momentum transfer cross-section and the gas density threshold for star formation. The DM halo forms a constant density core of similar size and shape for several combinations of those two parameters. Haloes with cores that are formed due to SIDM (adiabatic cusp-core transformation) have velocity dispersion profiles that are closer to isothermal than those of haloes with cores that are formed due to SNF in simulations with bursty star formation (impulsive cusp-core transformation). Impulsive SNF can generate positive stellar age gradients and increase random motion in the gas at the centre of the galaxy. Simulated galaxies in haloes with cores that were formed adiabatically are spatially more extended, with stellar metallicity gradients that are shallower (at late times) than those of galaxies in other simulations. Such observable properties of the gas and the stars, which indicate either an adiabatic or an impulsive evolution of the gravitational potential, may be used to determine whether observed cores in DM haloes are formed through DM self-interactions or in response to impulsive SNF.
PubDate: Mon, 11 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac994
Issue No: Vol. 513, No. 3 (2022)

• Serendipitous discovery of radio flaring behaviour from a nearby M dwarf
with MeerKAT

Authors: Andersson A; Fender R, Lintott C, et al.
Pages: 3482 - 3492
Abstract: ABSTRACTWe report on the detection of MKT J174641.0−321404, a new radio transient found in untargeted searches of wide-field MeerKAT radio images centred on the black hole X-ray binary H1743−322. MKT J174641.0−321404 is highly variable at 1.3 GHz and was detected three times during 11 observations of the field in late 2018, reaching a maximum flux density of 590 ± 60 µJy. We associate this radio transient with a high proper motion, M dwarf star SCR 1746−3214 12 pc away from the Sun. Multiwavelength observations of this M dwarf indicate flaring activity across the electromagnetic spectrum, consistent with emission expected from dMe stars, and providing upper limits on quiescent brightness in both the radio and X-ray regimes. TESS photometry reveals a rotational period for SCR 1746−3214 of 0.2292 ± 0.0025 d, which at its estimated radius makes the star a rapid rotator, comparable to other low-mass systems. Dedicated spectroscopic follow up confirms the star as a mid-late spectral M dwarf with clear magnetic activity indicated by strong H α emission. This transient’s serendipitous discovery by MeerKAT, along with multiwavelength characterization, make it a prime demonstration of both the capabilities of the current generation of radio interferometers and the value of simultaneous observations by optical facilities such as MeerLICHT. Our results build upon the literature of M dwarfs’ flaring behaviour, particularly relevant to the habitability of their planetary systems.
PubDate: Wed, 13 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1002
Issue No: Vol. 513, No. 3 (2022)

• Decomposing magnetic fields in three dimensions over the central molecular
zone

Authors: Hu Y; Lazarian A, Wang Q.
Pages: 3493 - 3509
Abstract: ABSTRACTMeasuring magnetic fields in the interstellar medium and obtaining their distribution along line-of-sight (LOS) is very challenging with the traditional techniques. The Velocity Gradient Technique (VGT), which utilizes anisotropy of magnetohydrodynamic turbulence, provides an attractive solution. Targeting the central molecular zone (CMZ), we test this approach by applying the VGT to $\rm ^{12}CO$ and $\rm ^{13}CO$ (J = 1–0) data cubes. We first used the scousepy algorithm to decompose the CO line emissions into separate velocity components, and then we constructed pseudo-Stokes parameters via the VGT to map the plane-of-the-sky magnetic fields in three-dimension. We present the decomposed magnetic field maps and investigate their significance. While the LOS integrated magnetic field orientation is shown to be consistent with the polarized dust emission from the Planck survey at 353 GHz, individual velocity components may exhibit different magnetic fields. We present a scheme of magnetic field configuration in the CMZ based on the decomposed magnetic fields. In particular, we observe a nearly vertical magnetic field orientation in the dense clump near the Sgr B2 and a change in the outflow regions around the Sgr A*. Two high-velocity structures associated with an expanding ring in the CMZ show distinct swirling magnetic field structures. These results demonstrate the potential power of the VGT to decompose velocity or density-dependent magnetic structures.
PubDate: Wed, 20 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1060
Issue No: Vol. 513, No. 3 (2022)

• The VANDELS survey: a measurement of the average Lyman-continuum escape
fraction of star-forming galaxies at z = 3.5

Authors: Begley R; Cullen F, McLure R, et al.
Pages: 3510 - 3525
Abstract: ABSTRACTWe present a study designed to measure the average Lyman-continuum escape fraction (〈fesc〉) of star-forming galaxies at z ≃ 3.5. We assemble a sample of 148 galaxies from the VANDELS spectroscopic survey at 3.35 ≤ zspec ≤ 3.95, selected to minimize line-of-sight contamination of their photometry. For this sample, we use ultra-deep, ground-based, U-band imaging and Hubble Space Telescope V-band imaging to robustly measure the distribution of $\mathcal {R_{\rm obs}}\, =(L_{\rm LyC}/L_{\rm UV})_{\rm obs}$. We then model the $\mathcal {R_{\rm obs}}$ distribution as a function of 〈fesc〉, carefully accounting for attenuation by dust, the intergalactic medium and the circumgalactic medium. A maximum likelihood fit to the $\mathcal {R_{\rm obs}}$ distribution returns a best-fitting value of $\langle f_{\rm esc}\rangle =0.07^{+0.02}_{-0.02}$, a result confirmed using an alternative Bayesian inference technique (both techniques exclude 〈fesc〉 = 0.0 at >3σ). By splitting our sample in two, we find evidence that 〈fesc〉 is positively correlated with Ly α equivalent width (Wλ(Ly α)), with high and low Wλ(Lyα) subsamples returning values of $\langle f_{\rm esc}\rangle =0.12^{+0.06}_{-0.04}$ and $\langle f_{\rm esc} \rangle =0.02^{+0.02}_{-0.01}$, respectively. In contrast, we find evidence that 〈fesc〉 is anticorrelated with intrinsic UV luminosity and UV dust attenuation; with low UV luminosity and dust attenuation subsamples both returning best fits in the range 0.10 ≤ 〈fesc〉 ≤ 0.22. We do not find a clear correlation between fesc and galaxy stellar mass, suggesting stellar mass is not a primary indicator of fesc. Although larger samples are needed to further explore these trends, our results suggest that it is entirely plausible that the low dust, low-metallicity galaxies found at z ≥ 6 will display the 〈fesc〉 ≥ 0.1 required to drive reionization.
PubDate: Tue, 19 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1067
Issue No: Vol. 513, No. 3 (2022)

• The escape of globular clusters from the satellite dwarf galaxies of the
Milky Way

Authors: Rostami Shirazi A; Haghi H, Khalaj P, et al.
Pages: 3526 - 3540
Abstract: ABSTRACTUsing numerical simulations, we have studied the escape of globular clusters (GCs) from the satellite dwarf spheroidal galaxies (dSphs) of the Milky Way (MW). We start by following the orbits of a large sample of GCs around dSphs in the presence of the MW potential field. We then obtain the fraction of GCs leaving their host dSphs within a Hubble time. We model dSphs by a Hernquist density profile with masses between $10^7$ and $7\times 10^9\, \mathrm{M}_{\odot }$. All dSphs lie on the Galactic disc plane, but they have different orbital eccentricities and apogalactic distances. We compute the escape fraction of GCs from 13 of the most massive dSphs of the MW, using their realistic orbits around the MW (as determined by Gaia). The escape fraction of GCs from 13 dSphs is in the range $12{{\ \rm per\ cent}}$ to $93{{\ \rm per\ cent}}$. The average escape time of GCs from these dSphs was less than 8 $\, \mathrm{Gyr}$, indicating that the escape process of GCs from dSphs was over. We then adopt a set of observationally constrained density profiles for specific case of the Fornax dSph. According to our results, the escape fraction of GCs shows a negative correlation with both the mass and the apogalactic distance of the dSphs, as well as a positive correlation with the orbital eccentricity of dSphs. In particular, we find that the escape fraction of GCs from the Fornax dSph is between $13{{\ \rm per\ cent}}$ and $38{{\ \rm per\ cent}}$. Finally, we observe that when GCs leave their host dSphs, their final orbit around the MW does not differ much from their host dSphs.
PubDate: Wed, 20 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1070
Issue No: Vol. 513, No. 3 (2022)

• Overestimated inclinations of Milgromian disc galaxies: the case of the

Authors: Banik I; Nagesh S, Haghi H, et al.
Pages: 3541 - 3548
Abstract: ABSTRACTWe present two hydrodynamical star-forming simulations in the Milgromian dynamics (MOND) framework of a gas-rich disc galaxy with properties similar to AGC 114905, which has recently been argued to have a rotation curve (RC) that is inconsistent with the MOND prediction. Our first model considers the galaxy in isolation, while our second model includes an external field of $0.05 \, a_{_0}$, the estimated gravitational field from large-scale structure. We show that isophotes in the face-on view can differ from circular at the 50 per cent level. This could mislead observers into overestimating the inclination i between disc and sky planes. Because RCs require a correction factor of 1/sin i, the actual RC could be much higher than that reported by observers. This plausibly reconciles AGC 114905 with MOND expectations.
PubDate: Tue, 19 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1073
Issue No: Vol. 513, No. 3 (2022)

• Correction

Pages: 3549 - 3549
Abstract: A change has been made to the author list in the following
DOI s: 10.1093/mnras/stz1466, 10.1093/mnras/stz1733, 10.1093/mnras/stx2045, 10.1093/mnras/sty495, 10.1093/mnras/stx2434, 10.1093/mnras/sty2950, 10.1093/mnras/stz470.
PubDate: Thu, 12 May 2022 00:00:00 GMT
Issue No: Vol. 513, No. 3 (2022)

• Where are the magnetar binary companions' Candidates from a comparison
with binary population synthesis predictions

Authors: Chrimes A; Levan A, Fruchter A, et al.
Pages: 3550 - 3563
Abstract: ABSTRACTIt is well established that magnetars are neutron stars with extreme magnetic fields and young ages, but the evolutionary pathways to their creation are still uncertain. Since most massive stars are in binaries, if magnetars are a frequent result of core-collapse supernovae, some fractions are expected to have a bound companion at the time of observation. In this paper, we utilize literature constraints, including deep Hubble Space Telescope imaging, to search for bound stellar companions to magnetars. The magnitude and colour measurements are interpreted in the context of binary population synthesis predictions. We find two candidates for stellar companions associated with CXOU J171405.7–381031 and SGR 0755–2933, based on their J–H colours and H-band absolute magnitudes. Overall, the proportion of the Galactic magnetar population with a plausibly stellar near-infrared (NIR) counterpart candidate, based on their magnitudes and colours, is between 5 and 10 per cent. This is consistent with a population synthesis prediction of 5 per cent, for the fraction of core-collapse neutron stars arising from primaries that remain bound to their companion after the supernova. These results are therefore consistent with magnetars being drawn in an unbiased way from the natal core-collapse neutron star population, but some contribution from alternative progenitor channels cannot be ruled out.
PubDate: Fri, 22 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1090
Issue No: Vol. 513, No. 3 (2022)

• An Hα survey of the host environments of 77 type IIn supernovae
within z &lt; 0.02

Authors: Ransome C; Habergham-Mawson S, Darnley M, et al.
Pages: 3564 - 3576
Abstract: ABSTRACTType IIn supernovae (SNe IIn) are an uncommon and highly heterogeneous class of SN where the SN ejecta interact with pre-existing circumstellar media (CSM). Previous studies have found a mass ladder in terms of the association of the SN location with H α emission and the progenitor masses of SN classes. In this paper, we present the largest environmental study of SNe IIn. We analyse the H α environments of 77 type SNeIIn using continuum subtracted H α images. We use the pixel statistics technique, normalized cumulative ranking (NCR), to associate SN pixels with H α emission. We find that our 77 SNe IIn do not follow the H α emission. This is not consistent with the proposed progenitors of SNe IIn, luminous blue variables (LBVs) as LBVs are high-mass stars that undergo dramatic episodic mass loss. However, a subset of the NCR values follow the H α emission, suggesting a population of high-mass progenitors. This suggests there may be multiple progenitor paths with ∼60 per cent having non-zero NCR values with a distribution consistent with high-mass progenitors such as LBVs and ∼40 per cent of these SNe not being associated with H α emission. We discuss the possible progenitor routes of SNe IIn, especially for the zero NCR value population. We also investigate the radial distribution of the SNe in their hosts in terms of H α and r′-band flux.
PubDate: Fri, 29 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1093
Issue No: Vol. 513, No. 3 (2022)

• Can a binary neutron star merger in the vicinity of a supermassive black
hole enable a detection of a post-merger gravitational wave signal'

Authors: Vijaykumar A; Kapadia S, Ajith P.
Pages: 3577 - 3586
Abstract: ABSTRACTThe post-merger gravitational-wave (GW) signal of a binary neutron star (BNS) merger is expected to contain valuable information that could shed light on the equation of state (EOS) of NSs, the properties of the matter produced during the merger, as well as the nature of any potential intermediate merger product such as hypermassive or supramassive NSs. However, the post-merger lies in the high frequency regime (≳1000 Hz) where current LIGO-Virgo detectors are insensitive. While proposed detectors such as NEMO, Cosmic Explorer and Einstein Telescope could potentially detect the post-merger for BNSs within $\mathcal {O}(10~\mathrm{Mpc})$, such events are likely to be rare. In this work, we speculate on the possibility of detecting the post-merger from BNSs coalescing in the vicinity of supermassive black holes (SMBHs). The redshift produced by the gravitational field of the SMBH, as well as the BNS’s proper motion around the SMBH, could effectively ‘stretch’ the post-merger signal into the band of the detectors. We demonstrate, using a phenomenological model, that such BNS coalescences would enable constraints on the peak of the post-merger signal that would otherwise have not been possible, provided the degree of redshifting due to the SMBH can be independently acquired. Further, using numerical simulations of binary neutron stars, we show how such mergers would improve EOS model selection using the post-merger signal. We discuss the mechanisms that might deliver such events and the limitations of this work.
PubDate: Mon, 25 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1131
Issue No: Vol. 513, No. 3 (2022)

• Close detached white dwarf + brown dwarf binaries: further evidence for
low values of the common envelope efficiency

Authors: Zorotovic M; Schreiber M.
Pages: 3587 - 3595
Abstract: ABSTRACTCommon envelope evolution is a fundamental ingredient in our understanding of the formation of close binary stars containing compact objects that include the progenitors of type Ia supernovae, short gamma-ray bursts, and most stellar gravitational wave sources. To predict the outcome of common envelope evolution, we still rely to a large degree on a simplified energy conservation equation. Unfortunately, this equation contains a theoretically rather poorly constrained efficiency parameter (αCE) and, even worse, it is unclear if energy sources in addition to orbital energy (such as recombination energy) contribute to the envelope ejection process. In previous works, we reconstructed the evolution of observed populations of post-common envelope binaries (PCEBs) consisting of white dwarfs with main-sequence star companions and found indications that the efficiency is rather small (αCE ≃ 0.2–0.3) and that extra energy sources are only required in very few cases. Here, we used the same reconstruction tool to investigate the evolutionary history of a sample of observed PCEBs with brown dwarf companions. In contrast to previous works, we found that the evolution of observationally well-characterized PCEBs with brown dwarf companions can be understood assuming a low common envelope efficiency (αCE = 0.24–0.41), similar to that required to understand PCEBs with main-sequence star companions, and that contributions from recombination energy are not required. We conclude that the vast majority of PCEBs form from common envelope evolution that can be parametrized with a small efficiency and without taking into account additional energy sources.
PubDate: Thu, 28 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1137
Issue No: Vol. 513, No. 3 (2022)

• Cosmology and neutrino mass with the minimum spanning tree

Authors: Naidoo K; Massara E, Lahav O.
Pages: 3596 - 3609
Abstract: ABSTRACTThe information content of the minimum spanning tree (MST), used to capture higher order statistics and information from the cosmic web, is compared to that of the power spectrum for a νΛCDM model. The measurements are made in redshift space using haloes from the Quijote simulation of mass $\ge 3.2\times 10^{13}\, h^{-1}\, {\rm M}_{\odot }$ in a box of length $L_{\rm box}=1\, h^{-1}\, {\rm Gpc}$. The power spectrum multipoles (monopole and quadrupole) are computed for Fourier modes in the range $0.006\, h{\rm Mpc}^{-1} \lt k \lt 0.5\, h{\rm Mpc}^{-1}$. For comparison the MST is measured with a minimum length-scale of $l_{\min }\simeq 13\, h^{-1}\, {\rm Mpc}$. Combining the MST and power spectrum allows for many of the individual degeneracies to be broken; on its own the MST provides tighter constraints on the sum of neutrino masses Mν and cosmological parameters h, ns, and Ωb but the power spectrum alone provides tighter constraints on Ωm and σ8. Combined we find constraints that are a factor of two (or greater) on all parameters with respect to the power spectrum (for Mν there is a factor of four improvement). These improvements appear to be driven by the MST’s sensitivity to small scale clustering, where the effect of neutrino free-streaming becomes relevant, and high-order statistical information in the cosmic web. The MST is shown to be a powerful tool for cosmology and neutrino mass studies, and therefore could play a pivotal role in ongoing and future galaxy redshift surveys (such as DES, DESI, Euclid, and Rubin-LSST).
PubDate: Wed, 27 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1138
Issue No: Vol. 513, No. 3 (2022)

• Fast map-based simulations of systematics in CMB surveys including effects
of the scanning strategy

Authors: McCallum N; Thomas D, Brown M.
Pages: 3610 - 3626
Abstract: ABSTRACTWe present approaches to quickly simulate systematics affecting CMB observations, including the effects of the scanning strategy. Using summary properties of the scan, we capture features of full time ordered data (TOD) simulations, allowing maps and power spectra to be generated at much improved speed for a number of systematics – the cases we present experienced speed ups of 3–4 orders of magnitude when implementing the map-based approaches. We demonstrate the effectiveness of the approaches at capturing the salient features of the scan by directly comparing to full TOD simulations – seeing agreement at sub-per cent levels of accuracy. We simulate the effects of differential gain, pointing, and ellipticity to show the effectiveness of the approaches, but note that one could extend these techniques to other systematics. We finally show how to apply these fast map-based simulations of systematic effects to a full focal plane showing their ability to incorporate thousands of detectors as seen in modern CMB experiments.
PubDate: Thu, 03 Mar 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac561
Issue No: Vol. 513, No. 3 (2022)

• Constraints on the abundance of supermassive primordial black holes from

Authors: Zhou H; Lian Y, Li Z, et al.
Pages: 3627 - 3633
Abstract: ABSTRACTThe possibility that primordial black holes (PBHs) form a part of dark matter has been considered over a wide mass range from the Planck mass ($10^{-5}~\rm g$) to the level of the supermassive black hole in the center of the galaxy. Primordial origin might be one of the most important formation channel of supermassive black holes. We use the non-detection of lensing effect of very long baseline interferometer observations of compact radio sources with extremely high angular resolution as a promising probe to constrain the abundance of intergalactic PBHs in the mass range ∼104–109 M⊙. For a sample of well-measured 543 flat-spectrum compact radio sources, no milli-lensed images are found with angular separations between 1.5 and 50 milli-arcsec. From this null search result, we derive that the fraction of dark matter made up of supermassive PBHs in the mass range ∼106–108 M⊙ is $\lesssim 1.48{{\ \rm per\, cent}}$ at $95{{\ \rm per\, cent}}$ confidence level. This constraints would be significantly improved due to the rapid increase of the number of measured compact radio sources. For instance, on the basis of none confirmed milli-lensing candidate in the latest ∼14 000 sources, we derive the abundance of supermassive PBHs and obtain that it is $\lesssim 0.06{{\ \rm per\, cent}}$ at $95{{\ \rm per\, cent}}$ confidence level.
PubDate: Tue, 05 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac915
Issue No: Vol. 513, No. 3 (2022)

• Jets in common envelopes: a low-mass main-sequence star in a red giant

Authors: López-Cámara D; De Colle F, Moreno Méndez E, et al.
Pages: 3634 - 3645
Abstract: ABSTRACTWe present small-scale 3D hydrodynamical simulations of the evolution of a 0.3 M⊙ main-sequence (MS) star that launches two perpendicular jets within the envelope of a 0.88 M⊙ red giant (RG). Based on previous large-scale simulations, we study the dynamics of the jets either when the secondary star is grazing, when it has plunged-in, or when it is well within the envelope of the RG (in each stage for ∼11 d). The dynamics of the jets through the common envelope (CE) depend on the conditions of the environment as well as on their powering. In the grazing stage and the commencement of the plunge self-regulated jets need higher efficiencies to break out of the envelope of the RG. Deep inside the CE, on the time-scales simulated, jets are choked independently of whether they are self-regulated or constantly powered. Jets able to break out of the envelope of the RG in large-scale simulations, are choked in our small-scale simulations. The accreted angular momentum on to the secondary star is not large enough to form a disc. The mass accretion on to the MS star is 1–10 per cent of the Bondi–Hoyle–Littleton rate (∼10−3–10−1 M⊙ yr−1). High-luminosity emission, from X-rays to ultraviolet and optical, is expected if the jets break out of the CE. Our simulations illustrate the need for inclusion of more realistic accretion and jet models in the dynamical evolution of the CEs.
PubDate: Fri, 15 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac932
Issue No: Vol. 513, No. 3 (2022)

• Impact of extreme spins and mass ratios on the post-merger observables of
high-mass binary neutron stars

Authors: Papenfort L; Most E, Tootle S, et al.
Pages: 3646 - 3662
Abstract: ABSTRACTThe gravitational-wave events GW170817 and GW190425 have led to a number of important insights on the equation of state of dense matter and the properties of neutron stars, such as their radii and the maximum mass. Some of these conclusions have been drawn on the basis of numerical-relativity simulations of binary neutron-star mergers with vanishing initial spins. While this may be a reasonable assumption in equal-mass systems, it may be violated in the presence of large mass asymmetries accompanied by the presence of high spins. To quantify the impact of high spins on multimessenger gravitational-wave events, we have carried out a series of high-mass binary neutron-star mergers with a highly spinning primary star and large mass asymmetries that have been modelled self-consistently using two temperature-dependent equations of state. We show that, when compared with equal-mass, irrotational binaries, these systems can lead to significant differences in the remnant lifetime, in the dynamical ejecta, in the remnant disc masses, in the secular ejecta, and on the bulk kilonova properties. These differences could be exploited to remove the degeneracy between low- and high-spin priors in the detection of gravitational waves from binary neutron-star mergers.
PubDate: Sat, 09 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac964
Issue No: Vol. 513, No. 3 (2022)

• Probing computational methodologies in predicting mid-infrared spectra for
large polycyclic aromatic hydrocarbons

Authors: Kerkeni B; García-Bernete I, Rigopoulou D, et al.
Pages: 3663 - 3681
Abstract: ABSTRACTWe extend the prediction of vibrational spectra to large sized polycyclic aromatic hydrocarbon (PAH) molecules comprising up to ∼1500 carbon atoms by evaluating the efficiency of several computational chemistry methodologies. We employ classical mechanics methods (Amber and Gaff) with improved atomic point charges, semi-empirical (PM3, and density functional tight binding), and density functional theory (B3LYP) and conduct global optimizations and frequency calculations in order to investigate the impact of PAH size on the vibrational band positions. We primarily focus on the following mid-infrared emission bands 3.3, 6.2, 7.7, 8.6, 11.3, 12.7, and 17.0 μm. We developed a general Frequency Scaling Function ($\mathcal {FSF}$) to shift the bands and to provide a systematic comparison versus the three methods for each PAH. We first validate this procedure on IR scaled spectra from the NASA Ames PAH Database, and extend it to new large PAHs. We show that when the $\mathcal {FSF}$ is applied to the Amber and Gaff IR spectra, an agreement between the normal mode peak positions with those inferred from the B3LYP/4-31G model chemistry is achieved. As calculations become time intensive for large sized molecules Nc > 450, this proposed methodology has advantages. The $\mathcal {FSF}$ has enabled extending the investigations to large PAHs where we clearly see the emergence of the 17.0 μm feature, and the weakening of the 3.3 μm one. We finally investigate the trends in the 3.3 μm/17.0 μm PAH band ratio as a function of PAH size and its response following the exposure to fields of varying radiation intensities.
PubDate: Wed, 20 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac976
Issue No: Vol. 513, No. 3 (2022)

• Stellar streams and dark substructure: the diffusion regime

Authors: Delos M; Schmidt F.
Pages: 3682 - 3708
Abstract: ABSTRACTThe cold dark matter picture predicts an abundance of substructure within the Galactic halo. However, most substructures host no stars and can only be detected indirectly. Stellar streams present a promising probe of this dark substructure. These streams arise from tidally stripped star clusters or dwarf galaxies, and their low dynamical temperature and negligible self-gravity give them a sharp memory of gravitational perturbations caused by passing dark substructures. For this reason, perturbed stellar streams have been the subject of substantial study. While previous studies have been largely numerical, we show here that in the diffusion regime – where stream stars are subjected to many small velocity kicks – stream perturbations can be understood on a fully analytic level. In particular, we derive how the (three-dimensional) power spectrum of the substructure density field determines the power spectrum of the (one-dimensional) density of a stellar stream. Our analytic description supplies a clear picture of the behaviour of stream perturbations in response to a perturbing environment, which may include contributions from both dark and luminous substructure. In particular, stream perturbations grow in amplitude initially, settle into a steady state, and ultimately decay. By directly relating stellar stream perturbations to the surrounding matter distribution, this analytic framework represents a versatile new tool for probing the nature of dark matter through astrophysical observations.
PubDate: Wed, 13 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1022
Issue No: Vol. 513, No. 3 (2022)

• The physical connection between central stellar surface density and
stellar spin in SAMI and MaNGA nearby galaxies

Authors: Cortese L; Fraser-McKelvie A, Woo J, et al.
Pages: 3709 - 3718
Abstract: ABSTRACTThe stellar surface density within the inner 1 kpc (Σ1) has become a popular tool for understanding the growth of galaxies and its connection with the quenching of star formation. The emerging picture suggests that building a central dense core is a necessary condition for quenching. However, it is not clear whether changes in Σ1 trace changes in stellar kinematics and the growth of dispersion-dominated bulges. In this paper, we combine imaging from the Sloan Digital Sky Survey with stellar kinematics from the Sydney-AAO Multi-object Integral-field unit and Mapping Nearby Galaxies at Apache Point Observatory surveys to quantify the correlation between Σ1 and the proxy for stellar spin parameter within one effective radius (λre) for 1599 nearby galaxies. We show that, on the star-forming main sequence and at fixed stellar mass, changes in Σ1 are mirrored by changes in λre. While forming stars, main-sequence galaxies remain rotationally-dominated systems, with their Σ1 increasing but their stellar spin staying either constant or slightly increasing. The picture changes below the main sequence, where Σ1 and λre are no longer correlated. Passive systems show a narrower range of Σ1, but a wider range of λre compared to star-forming galaxies. Our results indicate that, from a structural point of view, passive galaxies are a more heterogeneous population than star-forming systems, and may have followed a variety of evolutionary paths. This also suggests that, if dispersion-dominated bulges still grow significantly at z ∼ 0, this generally takes place during, or after, the quenching phase.
PubDate: Wed, 27 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1023
Issue No: Vol. 513, No. 3 (2022)

• Hybrid photometric redshifts for sources in the COSMOS and XMM-LSS fields

Authors: Hatfield P; Jarvis M, Adams N, et al.
Pages: 3719 - 3733
Abstract: ABSTRACTIn this paper, we present photometric redshifts for 2.7 million galaxies in the XMM-LSS and COSMOS fields, both with rich optical and near-infrared data from VISTA and HyperSuprimeCam. Both template fitting (using galaxy and active galactic nuclei templates within LePhare) and machine learning (using gpz) methods are run on the aperture photometry of sources selected in the Ks-band. The resulting predictions are then combined using a Hierarchical Bayesian model, to produce consensus photometric redshift point estimates and probability distribution functions that outperform each method individually. Our point estimates have a root mean square error of ∼0.08–0.09, and an outlier fraction of ∼3–4 percent when compared to spectroscopic redshifts. We also compare our results to the COSMOS2020 photometric redshifts, which contain fewer sources, but had access to a larger number of bands and greater wavelength coverage, finding that comparable photo-z quality can be achieved (for bright and intermediate luminosity sources where a direct comparison can be made). Our resulting redshifts represent the most accurate set of photometric redshifts (for a catalogue this large) for these deep multisquare degree multiwavelength fields to date.
PubDate: Fri, 15 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1042
Issue No: Vol. 513, No. 3 (2022)

• The ice-organic-silicate contents of small Solar system bodies: indicators
for a comet to asteroid evolutionary pathway

Authors: H; Potiszil C, Tanaka R, et al.
Pages: 3734 - 3741
Abstract: ABSTRACTComets and asteroids have traditionally been separated categories, but main belt comets skew this view, portraying a possible intermediate stage between these two end members. Investigating the relationship between these bodies can improve our understanding of the formation and evolution of the Solar system and help to identify potentially interesting parent bodies from within our Solar system, for future sample return missions. Furthermore, elucidating the ice-organic-silicate ratios of potential meteorite parent bodies can help to explain the observed isotopic ratios and petrography of meteorite samples. While the ice-organic-silicate ratios of particular bodies have been estimated, there has been no study undertaken which compares different types of bodies in terms of their ice-organic-silicate ratios. Therefore, this study presents a geophysical-chemical mass balance model, to estimate the ice-organic-silicate ratios of comets, main belt comets, and asteroids. The results drawn from the model form a diagonal trend upon an ice-organic-silicate ternary diagram, in which comets and main belt comets plot together at generally higher ice contents, with asteroids typically plotting at lower ice contents. However, an overlap between all three body types is observed and supports the scenario in which comets, main belt comets, and asteroids are genetically linked.
PubDate: Wed, 20 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1068
Issue No: Vol. 513, No. 3 (2022)

• Cosmic evolution of low-excitation radio galaxies in the LOFAR two-metre
sky survey deep fields

Authors: Kondapally R; Best P, Cochrane R, et al.
Pages: 3742 - 3767
Abstract: ABSTRACTFeedback from low-excitation radio galaxies (LERGs) plays a key role in the lifecycle of massive galaxies in the local Universe; their evolution, and the impact of these active galactic nuclei on early galaxy evolution, however, remain poorly understood. We use a sample of 10 481 LERGs from the first data release of the LOFAR two-metre Sky Survey Deep Fields, covering ∼25 deg2, to present the first measurement of the evolution of the radio luminosity function (LF) of LERGs out to z ∼ 2.5; this shows relatively mild evolution. We split the LERGs into those hosted by quiescent and star-forming galaxies, finding a new dominant population of LERGs hosted by star-forming galaxies at high redshifts. The incidence of LERGs in quiescent galaxies shows a steep dependence on stellar mass out to z ∼ 1.5, consistent with local Universe measurements of accretion occurring from cooling of hot gas haloes. The quiescent-LERGs dominate the LFs at z < 1, showing a strong decline in space density with redshift, tracing that of the available host galaxies, while there is an increase in the characteristic luminosity. The star-forming LERG LF increases with redshift, such that this population dominates the space densities at most radio-luminosities by z ∼ 1. The incidence of LERGs in star-forming galaxies shows a much weaker stellar-mass dependence, and increases with redshift, suggesting a different fuelling mechanism compared to their quiescent counterparts, potentially associated with the cold gas supply present in the star-forming galaxies.
PubDate: Tue, 26 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1128
Issue No: Vol. 513, No. 3 (2022)

• The effects of AGN feedback on the structural and dynamical properties of
Milky Way-mass galaxies in cosmological simulations

Authors: Irodotou D; Fragkoudi F, Pakmor R, et al.
Pages: 3768 - 3787
Abstract: ABSTRACTFeedback from active galactic nuclei (AGNs) has become established as a fundamental process in the evolution of the most massive galaxies. Its impact on Milky Way (MW)-mass systems, however, remains comparatively unexplored. In this work, we use the auriga simulations to probe the impact of AGN feedback on the dynamical and structural properties of galaxies, focusing on the bar, bulge, and disc. We analyse three galaxies – two strongly and one unbarred/weakly barred – using three setups: (i) the fiducial auriga model, which includes both radio and quasar mode feedback, (ii) a setup with no radio mode, and (iii) one with neither the radio nor the quasar mode. When removing the radio mode, gas in the circumgalactic medium cools more efficiently and subsequently settles in an extended disc, with little effect on the inner disc. Contrary to previous studies, we find that although the removal of the quasar mode results in more massive central components, these are in the form of compact discs, rather than spheroidal bulges. Therefore, galaxies without quasar mode feedback are more baryon-dominated and thus prone to forming stronger and shorter bars, which reveals an anticorrelation between the ejective nature of AGN feedback and bar strength. Hence, we report that the effect of AGN feedback (i.e. ejective or preventive) can significantly alter the dynamical properties of MW-like galaxies. Therefore, the observed dynamical and structural properties of MW-mass galaxies can be used as additional constraints for calibrating the efficiency of AGN feedback models.
PubDate: Thu, 28 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1143
Issue No: Vol. 513, No. 3 (2022)

• Compact star merger events with stars composed of interacting strange
quark matter

Authors: Kumar A; Thapa V, Sinha M.
Pages: 3788 - 3797
Abstract: ABSTRACTWe investigate the properties of stars participating in double compact star merger events considering interacting model of stable strange quark matter. We model the matter making it compatible with the recent astrophysical observations of compact star mass–radius and gravitational wave events. In this context, we consider modified MIT bag model and vector bag model with and without self-interaction. We find new upper bound on tidal deformability of $1.4\, {\rm M}_\odot$ strange star corresponding to the upper bound of effective tidal deformability inferred from gravitational wave event. Range of compactness of $1.4\, {\rm M}_\odot$ strange star is obtained as 0.175 ≤ C1.4 ≤ 0.199. Radius range of $1.5\, {\rm M}_\odot$ primary star is deduced to be 10.57 km ≤ R1.5 ≤ 12.04 km, following stringent GW170817 constraints. GW190425 constraints provide with upper limit on radius of 1.7 solar mass strange star that it should be less than $13.41\, \text{km}$.
PubDate: Thu, 28 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1150
Issue No: Vol. 513, No. 3 (2022)

• Improved early-warning estimates of luminosity distance and orbital
inclination of compact binary mergers using higher modes of gravitational

Authors: Singh M; D, Kapadia S, et al.
Pages: 3798 - 3809
Abstract: ABSTRACTThe pre-merger (early-warning) gravitational-wave (GW) detection and localization of a compact binary merger would enable astronomers to capture potential electromagnetic (EM) emissions around the time of the merger, thus shedding light on the complex physics of the merger. While early detection and sky localization are of primary importance to the multimessenger follow-up, improved estimates of luminosity distance and orbital inclination could also provide insights on the observability of EM emission. In this work, we demonstrate that the inclusion of higher modes of gravitational radiation, which vibrate at higher multiples of the orbital frequency than the dominant mode, would significantly improve the early-warning estimates of the luminosity distance and orbital inclination of asymmetric compact binaries, in particular, neutron-star black hole mergers. This will help astronomers to better determine their follow-up strategy of such systems. Focusing on future observing runs of the ground-based GW detectors, we show that for neutron-star black hole binaries that are potentially EM-bright, the inclusion of higher modes improves the luminosity distance estimates by a factor of ∼1 − 1.5 (1.1 − 2) [1.1 − 5] for the O5 (Voyager) [3G] observing scenario, 45 (45) [300] s before the merger. There are significant improvements in orbital inclination estimates as well. We also investigate these improvements with varying sky-location and polarization angle. Combining the luminosity distance uncertainties with localization skyarea estimates, we find that the number of galaxies within localization volume is reduced by a factor of ∼1 − 2.5 (1.2 − 4) [1.2 − 10] with the inclusion of higher modes in O5 (Voyager) [3G].
PubDate: Mon, 28 Mar 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac852
Issue No: Vol. 513, No. 3 (2022)

• Shocked jets in CCSNe can power the zoo of fast blue optical transients

Authors: Gottlieb O; Tchekhovskoy A, Margutti R.
Pages: 3810 - 3817
Abstract: ABSTRACTEvidence is mounting that recent multiwavelength detections of fast blue optical transients (FBOTs) in star-forming galaxies comprise a new class of transients, whose origin is yet to be understood. We show that hydrogen-rich collapsing stars that launch relativistic jets near the central engine can naturally explain the entire set of FBOT observables. The jet–star interaction forms a mildly relativistic shocked jet (inner cocoon) component, which powers cooling emission that dominates the high velocity optical signal during the first few weeks, with a typical energy of ∼1050–1051 erg. During this time, the cocoon radial energy distribution implies that the optical light curve exhibits a fast decay of $L \,\, \buildrel\propto \over \sim \,\,t^{-2.4}$. After a few weeks, when the velocity of the emitting shell is ∼0.01 c, the cocoon becomes transparent, and the cooling envelope governs the emission. The interaction between the cocoon and the dense circumstellar winds generates synchrotron self-absorbed emission in the radio bands, featuring a steady rise on a month time-scale. After a few months the relativistic outflow decelerates, enters the observer’s line of sight, and powers the peak of the radio light curve, which rapidly decays thereafter. The jet (and the inner cocoon) becomes optically thin to X-rays ∼day after the collapse, allowing X-ray photons to diffuse from the central engine that launched the jet to the observer. Cocoon cooling emission is expected at higher volumetric rates than gamma-ray bursts (GRBs) by a factor of a few, similar to FBOTs. We rule out uncollimated outflows, however, both GRB jets and failed collimated jets are compatible with all observables.
PubDate: Mon, 11 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac910
Issue No: Vol. 513, No. 3 (2022)

• The MAVERIC survey: a catalogue of radio sources in southern globular
clusters from the Australia Telescope Compact Array

Authors: Tudor V; Miller-Jones J, Strader J, et al.
Pages: 3818 - 3835
Abstract: ABSTRACTRadio continuum observations offer a new window on compact objects in globular clusters compared to typical X-ray or optical studies. As part of the MAVERIC survey, we have used the Australia Telescope Compact Array to carry out a deep (median central noise level ≈4 $\mu$Jy beam-1) radio continuum survey of 26 southern globular clusters at central frequencies of 5.5 and 9.0 GHz. This paper presents a catalogue of 1285 radio continuum sources in the fields of these 26 clusters. Considering the surface density of background sources, we find significant evidence for a population of radio sources in seven of the 26 clusters, and also identify at least 11 previously known compact objects (six pulsars and five X-ray binaries). While the overall density of radio continuum sources with 7.25-GHz flux densities ≳ 20 $\mu$Jy in typical globular clusters is relatively low, the survey has already led to the discovery of several exciting compact binaries, including a candidate ultracompact black hole X-ray binary in 47 Tuc. Many of the unclassified radio sources near the centres of the clusters are likely to be true cluster sources, and multiwavelength follow-up will be necessary to classify these objects and better understand the demographics of accreting compact binaries in globular clusters.
PubDate: Thu, 14 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1034
Issue No: Vol. 513, No. 3 (2022)

• Host galaxies of ultrastrong Mg ii absorbers at z ∼ 0.5

Authors: Guha L; Srianand R, Dutta R, et al.
Pages: 3836 - 3857
Abstract: ABSTRACTFrom a sample of 109 candidate ultrastrong Mg ii (USMg ii; having rest equivalent width of Mg ii, W2796 > 3.0 Å) systems at z = 0.4–0.6, we confirm 27 and identify host galaxies of 20 systems based on associated nebular line emission from our SALT observations or from Sloan Digital Sky Survey (SDSS) fiber spectra. The measured impact parameter, [O ii] luminosity, star formation rate, B-band luminosity, and stellar mass are in the ranges 7.3 ≤ D[kpc] ≤ 79, $0.2\le L_{[\mathrm{ O}\,~\small {\rm II}]}[ 10^{41}~\mathrm{ erg} \mathrm{ s}^{-1}]\le 4.5$, 2.59 ≤ SFR[M⊙yr−1] ≤ 33.51, $0.15L_B^{*}\le L_B\le 1.63L_B^{*}$, and 10.21 ≤ log[M*/ M ⊙] ≤ 11.62, respectively. The impact parameters found are larger than that predicted by the W2796 versus D relationship of the general population of Mg ii absorbers. At a given D, USMg ii host galaxies are more luminous and massive compared to typical Mg ii absorbers. However, the measured SFRs are slightly lower than that of main-sequence galaxies with same M⋆ at z ∼ 0.5. We report a correlation between $L_{[\mathrm{ O}\,\small {\rm II}]}$ and W2796 for the full population of Mg ii absorbers, driven mainly by the host galaxies of weak Mg ii absorbers that tend to have low $L_{[\mathrm{ O}\,\small {\rm II}]}$ and large impact parameters. We find at least ∼33 per cent of the USMg ii host galaxies (with a limiting magnitude of mr < 23.6) are isolated and the large W2796 in these cases may originate from gas flows (infall/outflow) in single haloes of massive but not starburst galaxies. We also find galaxy interactions could be responsible for large velocity widths in at least ∼17 per cent cases.
PubDate: Tue, 26 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1106
Issue No: Vol. 513, No. 3 (2022)

• Circular polarimetry of suspect wind-accreting magnetic pre-polars

Authors: Hakala P; Parsons S, Marsh T, et al.
Pages: 3858 - 3870
Abstract: ABSTRACTWe present results from a circular polarimetric survey of candidate detached magnetic white dwarf – M dwarf binaries obtained using the Nordic Optical Telescope, La Palma. We obtained phase resolved spectropolarimetry and imaging polarimetry of seven systems, five of which show clearly variable circular polarisation. The data indicate that these targets have white dwarfs with magnetic field strengths >80 MG. Our study reveals that cyclotron emission can dominate the optical luminosity at wavelengths corresponding to the cyclotron emission harmonics, even in systems where the white dwarfs are only wind-accreting. This implies that a very significant fraction of the stellar wind of the companion star is captured by the magnetic white dwarf reducing the magnetic braking in pre-cataclysmic variables (CVs). Furthermore, the polarimetric confirmation of several detached, wind-accreting magnetic systems provides observational constraints on the models of magnetic CV evolution and white dwarf magnetic field generation. We also find that the white dwarf magnetic field configuration in at least two of these systems appears to be very complex.
PubDate: Mon, 25 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1111
Issue No: Vol. 513, No. 3 (2022)

• Reconciling the results of the z ∼ 2 MOSDEF and KBSS-MOSFIRE Surveys

Authors: Runco J; Reddy N, Shapley A, et al.
Pages: 3871 - 3892
Abstract: ABSTRACTThe combination of the MOSDEF and KBSS-MOSFIRE surveys represents the largest joint investment of Keck/MOSFIRE time to date, with ∼3000 galaxies at 1.4 ≲ z ≲ 3.8, roughly half of which are at z ∼ 2. MOSDEF is photometric- and spectroscopic-redshift selected with a rest-optical magnitude limit, while KBSS-MOSFIRE is primarily selected based on rest-UV colours and a rest-UV magnitude limit. Analysing both surveys in a uniform manner with consistent spectral-energy-distribution (SED) models, we find that the MOSDEF z ∼ 2 targeted sample has higher median M* and redder rest U−V colour than the KBSS-MOSFIRE z ∼ 2 targeted sample, and smaller median SED-based SFR and sSFR (SFR(SED) and sSFR(SED)). Specifically, MOSDEF targeted a larger population of red galaxies with U−V and V−J ≥1.25, while KBSS-MOSFIRE contains more young galaxies with intense star formation. Despite these differences in the z ∼ 2 targeted samples, the subsets of the surveys with multiple emission lines detected and analysed in previous work are much more similar. All median host-galaxy properties with the exception of stellar population age – i.e. M*, SFR(SED), sSFR(SED), AV, and UVJ colours – agree within the uncertainties. Additionally, when uniform emission-line fitting and stellar Balmer absorption correction techniques are applied, there is no significant offset between both samples in the [O iii]λ5008/H β versus [N ii]λ6585/H α diagnostic diagram, in contrast to previously reported discrepancies. We can now combine the MOSDEF and KBSS-MOSFIRE surveys to form the largest z ∼ 2 sample with moderate-resolution rest-optical spectra and construct the fundamental scaling relations of star-forming galaxies during this important epoch.
PubDate: Fri, 29 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1115
Issue No: Vol. 513, No. 3 (2022)

• Newcomers and suburbanites can drive the evolution of the size–stellar
mass relation of early-type galaxies in galaxy clusters

Authors: Matteuzzi M; Marinacci F, Nipoti C, et al.
Pages: 3893 - 3905
Abstract: ABSTRACTAt fixed stellar mass M*, the effective radius Re of massive satellite early-type galaxies (ETGs) in galaxy clusters is, on average, larger at lower redshift. We study theoretically this size evolution using the state-of-the-art cosmological simulation IllustrisTNG100: we sampled 75 simulated satellite ETGs at redshift z = 0 with M* ≥ 1010.4M⊙ belonging to the two most massive (≈1014.6M⊙) haloes of the simulation. We traced back in time the two clusters’ main progenitors and we selected their satellite ETGs at z > 0 with the same criterion adopted at z = 0. The Re–M* relation of the simulated cluster satellite ETGs, which is robustly measured out to z = 0.85, evolves similarly to the observed relation over the redshift range 0 ≲ z ≲ 0.85. In the simulation the main drivers of this evolution are the acquisition of new galaxies (‘newcomers') by the clusters and the transformation of member galaxies located at large cluster-centric distance (‘suburbanites’) at z = 0.85, which end up being massive satellite ETGs at z = 0. Though several physical processes contribute to change the population of satellite ETGs in the considered redshift interval, the shape of the stellar mass function of the simulated cluster ETGs is not significantly different at z = 0.85 and at z = 0, consistent with observations.
PubDate: Fri, 29 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1116
Issue No: Vol. 513, No. 3 (2022)

• On the viability of determining galaxy properties from observations – I.
Star formation rates and kinematics

Authors: Grisdale K; Hogan L, Rigopoulou D, et al.
Pages: 3906 - 3924
Abstract: ABSTRACTWe explore how observations relate to the physical properties of the emitting galaxies by post-processing a pair of merging z ∼ 2 galaxies from the cosmological, hydrodynamical simulation NewHorizon, using lcars (Light from Cloudy Added to RAMSES) to encode the physical properties of the simulated galaxy into H α emission line. By carrying out mock observations and analysis on these data cubes, we ascertain which physical properties of the galaxy will be recoverable with the HARMONI spectrograph on the European Extremely Large Telescope (ELT). We are able to estimate the galaxy’s star formation rate and dynamical mass to a reasonable degree of accuracy, with values within a factor of 1.81 and 1.38 of the true value. The kinematic structure of the galaxy is also recovered in mock observations. Furthermore, we are able to recover radial profiles of the velocity dispersion and are therefore able to calculate how the dynamical ratio varies as a function of distance from the galaxy centre. Finally, we show that when calculated on galaxy scales the dynamical ratio does not always provide a reliable measure of a galaxy’s stability against gravity or act as an indicator of a minor merger.
PubDate: Wed, 27 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1124
Issue No: Vol. 513, No. 3 (2022)

• Radial distributions of globular clusters trace their host dark matter
halo: insights from the E-MOSAICS simulations

Authors: Reina-Campos M; Trujillo-Gomez S, Deason A, et al.
Pages: 3925 - 3945
Abstract: ABSTRACTGlobular clusters (GCs) are bright objects that span a wide range of galactocentric distances, and can therefore probe the structure of dark matter (DM) haloes. In this work, we explore whether the projected number density radial profiles of GCs can be used to infer the structural properties of their host DM haloes. We use the simulated GC populations in a sample of 166 central galaxies from the $(34.4~\rm cMpc)^3$ periodic volume of the E-MOSAICS project. We find that more massive galaxies host stellar and GC populations with shallower density profiles that are more radially extended. In addition, metal-poor GC subpopulations tend to have shallower and more extended profiles than metal-rich subsamples, which we relate to the preferentially accreted origin of metal-poor GCs. We find strong correlations between the power-law slopes and effective radii of the radial profiles of the GC populations and the structural properties of the DM haloes, such as their power-law slopes, Navarro–Frenk–White scale radii, and concentration parameters. Accounting for a dependence on the galaxy stellar mass decreases the scatter of the two-dimensional relations. This suggests that the projected number counts of GCs, combined with their galaxy mass, trace the density profile of the DM halo of their host galaxy. When applied to extragalactic GC systems, we recover the scale radii and the extent of the DM haloes of a sample of early-type galaxies with uncertainties smaller than $0.2~\rm dex$. Thus, extragalactic GC systems provide a novel avenue to explore the structure of DM haloes beyond the Local Group.
PubDate: Wed, 27 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1126
Issue No: Vol. 513, No. 3 (2022)

• Clusters of galaxies up to z = 1.5 identified from photometric data of the
Dark Energy Survey and unWISE

Authors: Wen Z; Han J.
Pages: 3946 - 3959
Abstract: ABSTRACTUsing photometric data from the Dark Energy Survey and the Wide-field Infrared Survey Explorer, we estimate photometric redshifts for 105 million galaxies using the nearest-neighbour algorithm. From such a large data base, 151 244 clusters of galaxies are identified in the redshift range of 0.1 < z ≲ 1.5 based on the overdensity of the total stellar mass of galaxies within a given photometric redshift slice, among which 76 826 clusters are newly identified and 30 477 clusters have a redshift z > 1. We cross-match these clusters with those in the catalogues identified from the X-ray surveys and the Sunyaev–Zel’dovich (SZ) effect by the Planck, South Pole Telescope and Atacama Cosmology Telescope surveys, and get the redshifts for 45 X-ray clusters and 56 SZ clusters. More than 95 per cent SZ clusters in the sky region have counterparts in our catalogue. We find multiple optical clusters in the line of sight towards about 15 per cent of SZ clusters.
PubDate: Thu, 28 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1149
Issue No: Vol. 513, No. 3 (2022)

• Relativistic global solutions of neutrino-dominated accretion flows with
magnetic coupling

Authors: She J; Liu T, Xue L.
Pages: 3960 - 3970
Abstract: ABSTRACTA Kerr black hole (BH) surrounded by a neutrino-dominated accretion flow (NDAF) is one of plausible candidates of the central engine in gamma-ray bursts. The accretion material might inherit and restructure strong magnetic fields from the compact object mergers or massive collapsars. The magnetic coupling (MC) process between a rapid rotating BH and an accretion disc is one of possible magnetic configurations that transfers the energy and angular momentum from the BH to the disc. In this paper, we investigate one-dimensional global solutions of NDAFs with MC (MCNDAFs), taking into account general relativistic effects, detailed neutrino physics, different MC geometries, and reasonable nucleosynthesis processes. Six cases with different accretion rates and power-law indices of magnetic fields are presented and compared with NDAFs without MC. Our results indict that the MC process can prominently impact the structure, thermal properties, and microphysics of MCNDAFs, increase luminosities of neutrinos and their annihilations, result in the changing of radial distributions of nucleons, and push the region of heavy nuclei synthesis to a larger radius than counterparts in NDAFs.
PubDate: Wed, 27 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1154
Issue No: Vol. 513, No. 3 (2022)

• Correction to: Simulations of primary beam effects on the cosmic
bispectrum phase observed with the Hydrogen Epoch of Reionization Array

Pages: 3971 - 3971
Abstract: This is a correction to: N. Charles, G. Bernardi, H. L. Bester, O. M. Smirnov, C. Carilli, P. M. Keller, N. Kern, B. Nikolic, N. Thyagarajan, E. de Lera Acedo, N. Fagnoni, M. G. Santos, Simulations of primary beam effects on the cosmic bispectrum phase observed with the Hydrogen Epoch of Reionization Array, Monthly Notices of the Royal Astronomical Society, Volume 512, Issue 2, May 2022, Pages 2716–2727, https://doi.org/10.1093/mnras/stac709
PubDate: Sat, 14 May 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1157
Issue No: Vol. 513, No. 3 (2022)

• Automatic detection of low surface brightness galaxies from Sloan Digital
Sky Survey images

Authors: Yi Z; Li J, Du W, et al.
Pages: 3972 - 3981
Abstract: ABSTRACTLow surface brightness (LSB) galaxies are galaxies with central surface brightness fainter than the night sky. Due to the faint nature of LSB galaxies and the comparable sky background, it is difficult to search LSB galaxies automatically and efficiently from large sky survey. In this study, we established the low surface brightness galaxies autodetect (LSBG-AD) model, which is a data-driven model for end-to-end detection of LSB galaxies from Sloan Digital Sky Survey (SDSS) images. Object-detection techniques based on deep learning are applied to the SDSS field images to identify LSB galaxies and estimate their coordinates at the same time. Applying LSBG-AD to 1120 SDSS images, we detected 1197 LSB galaxy candidates, of which 1081 samples are already known and 116 samples are newly found candidates. The B-band central surface brightness of the candidates searched by the model ranges from 22 to 24 mag arcsec−2, quite consistent with the surface brightness distribution of the standard sample. A total of 96.46 per cent of LSB galaxy candidates have an axial ratio (b/a) greater than 0.3, and 92.04 per cent of them have $fracDev\_r$ < 0.4, which is also consistent with the standard sample. The results show that the LSBG-AD model learns the features of LSB galaxies of the training samples well, and can be used to search LSB galaxies without using photometric parameters. Next, this method will be used to develop efficient algorithms to detect LSB galaxies from massive images of the next-generation observatories.
PubDate: Wed, 23 Mar 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac775
Issue No: Vol. 513, No. 3 (2022)

• Hydrogen emission from meteors and meteorites: mapping traces of H2O
molecules and organic compounds in small Solar system bodies

Authors: Matlovič P; Pisarčíková A, Tóth J, et al.
Pages: 3982 - 3992
Abstract: ABSTRACTThe hydrogen emission from meteors is assumed to originate mainly from the meteoroid composition, making it a potential tracer of H2O molecules and organic compounds. H α line was previously detected in individual fireballs, but its variation in a larger meteor data set and dependence on the dynamical origin and physical properties have not yet been studied. Here, we investigate the relative intensity of H α within 304 meteor spectra observed by the AMOS (All-sky Meteor Orbit System) network. We demonstrate that H α emission is favoured in faster meteors (vi > > 30 km s−1) which form the high-temperature spectral component. H α was found to be a characteristic spectral feature of cometary meteoroids with ∼92 per cent of all meteoroids with detected H α originating from Halley-type and long-period orbits. Our results suggest that hydrogen is being depleted from meteoroids with lower perihelion distances (q < 0.4 au). No asteroidal meteoroids with detected H emission were found. However, using spectral data from simulated ablation of different meteorite types, we show that H emission from asteroidal materials can occur, and apparently correlates with their water and organic matter content. Strongest H emission was detected from carbonaceous chondrites (CM and CV) and achondrites (ureilite and aubrite), while it was lacking in most ordinary chondrites. The detection of H α in asteroidal meteoroids could be used to identify meteoroids of carbonaceous or achondritic composition. Overall, our results suggest that H α emission correlates with the emission of other volatiles (Na and CN) and presents a suitable tracer of water and organic matter in meteoroids.
PubDate: Sat, 23 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac927
Issue No: Vol. 513, No. 3 (2022)

• Spectroscopic analysis of VVV CL001 cluster with MUSE

Authors: Olivares Carvajal J; Zoccali M, Rojas-Arriagada A, et al.
Pages: 3993 - 4003
Abstract: ABSTRACTLike most spiral galaxies, the Milky Way contains a population of blue, metal-poor globular clusters and another of red, metal-rich ones. Most of the latter belong to the bulge, and therefore they are poorly studied compared to the blue (halo) ones because they suffer higher extinction and larger contamination from field stars. These intrinsic difficulties, together with a lack of low-mass bulge globular clusters, are reasons to believe that their census is not complete yet. Indeed, a few new clusters have been confirmed in the last few years. One of them is VVV CL001, the subject of the present study. We present a new spectroscopic analysis of the recently confirmed globular cluster VVV CL001, made by means of MUSE@VLT integral field data. Individual spectra were extracted for stars in the VVV CL001 field. Radial velocities were derived by cross-correlation with synthetic templates. Coupled with proper motions from the VVV (VISTA Variables in the Vía Láctea) survey, these data allow us to select 55 potential cluster members, for which we derive metallicities using the public code The Cannon. The mean radial velocity of the cluster is Vhelio = −324.9 ± 0.8 km s−1, as estimated from 55 cluster members. This high velocity, together with a low metallicity [Fe/H] = −2.04 ± 0.02 dex, suggests that VVV CL001 could be a very old cluster. The estimated distance is d = 8.23 ± 0.46 kpc, placing the cluster in the Galactic bulge. Furthermore, both its current position and the orbital parameters suggest that VVV CL001 is most probably a bulge globular cluster.
PubDate: Thu, 07 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac934
Issue No: Vol. 513, No. 3 (2022)

• The resilience of the Etherington–Hubble relation

Authors: Renzi F; Hogg N, Giarè W.
Pages: 4004 - 4014
Abstract: ABSTRACTThe Etherington reciprocity theorem, or distance duality relation (DDR), relates the mutual scaling of cosmic distances in any metric theory of gravity where photons are massless and propagate on null geodesics. In this paper, we make use of the DDR to build a consistency check based on its degeneracy with the Hubble constant, H0. We parametrize the DDR using the form η(z) = 1 + ϵz, thus only allowing small deviations from its standard value. We use a combination of late-time observational data to provide the first joint constraints on the Hubble parameter and ϵ with percentage accuracy: H0 = 68.6 ± 2.5 km s−1 Mpc−1 and $\epsilon = 0.001^{+0.023}_{-0.026}$. We build our consistency check using these constraints and compare them with the results obtained in extended cosmological models using cosmic microwave background data. We find that extensions to Λ cold dark matter (ΛCDM) involving massive neutrinos and/or additional dark radiation are in perfect agreement with the DDR, while models with non-zero spatial curvature show a preference for DDR violation, i.e. ϵ ≠ 0 at the level of ∼1.5σ. Most importantly, we find a mild 2σ discrepancy between the validity of the DDR and the latest publicly available Cepheid-calibrated Type Ia supernova (SNIa) constraint on H0. We discuss the potential consequences of this for both the Etherington reciprocity theorem and the H0 tension.
PubDate: Wed, 13 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1030
Issue No: Vol. 513, No. 3 (2022)

• Chemical diversity of the atmospheres and interiors of sub-Neptunes: a
case study of GJ 436 b

Authors: Guzmán-Mesa A; Kitzmann D, Mordasini C, et al.
Pages: 4015 - 4036
Abstract: ABSTRACTThe atmospheres of sub-Neptunes are expected to exhibit considerable chemical diversity, beyond what is anticipated for gas-giant exoplanets. In the current study, we construct self-consistent radiative transfer and equilibrium chemistry models to explore this chemical diversity. We use GJ 436 b as a case study to further study joint atmosphere-interior models. In particular, we constrain the properties of the interior and atmosphere of the planet based on the available Spitzer measurements. While it is possible to fit the emission spectrum of GJ 436 b using a high-metallicity model, we demonstrate that such an atmosphere is inconsistent with physically plausible interior structures. It remains the case that no existing study can adequately fit the 4.5-$\mu$m Spitzer secondary eclipse measurement, which is probably caused by chemical disequilibrium. Finally, an information content analysis reveals that emission and transmission spectra constrain the carbon-to-oxygen ratio and metallicity at different wavelengths, but the former are less susceptible to flat spectra stemming from highly metal-enriched atmospheres. With the recently launched James Webb Space Telescope, we recommend that future analysis of emission and transmission spectra of sub-Neptune planets are carried out self-consistently using both the atmospheric and interior structure models.
PubDate: Wed, 20 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1066
Issue No: Vol. 513, No. 3 (2022)

• Detection of quasi-periodic micro-structure in three millisecond pulsars
with the Large European Array for Pulsars

Authors: Liu K; Antoniadis J, Bassa C, et al.
Pages: 4037 - 4044
Abstract: ABSTRACTWe report on the detection of quasi-periodic micro-structure in three millisecond pulsars (MSPs), PSRs J1022+1001, J2145−0750, and J1744−1134, using high time resolution data acquired with the Large European Array for Pulsars at a radio frequency of 1.4 GHz. The occurrence rate of quasi-periodic micro-structure is consistent among pulses with different peak flux densities. Using an auto-correlation analysis, we measure the periodicity and width of the micro-structure in these three pulsars. The detected micro-structure from PSRs J1022+1001 and J1744−1134 is often highly linearly polarized. In PSR J1022+1001, the linear polarization position angles of micro-structure pulses are in general flat with a small degree of variation. Using these results, we further examine the frequency and rotational period dependency of micro-structure properties established in previous work, along with the angular beaming and temporal modulation models that explain the appearance of micro-structure. We also discuss a possible link of micro-structure to the properties of some of the recently discovered fast radio bursts which exhibit a very similar emission morphology.
PubDate: Wed, 27 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1082
Issue No: Vol. 513, No. 3 (2022)

• Constraining equation-of-state groups from g-mode asteroseismology

Authors: Kuan H; Krüger C, Suvorov A, et al.
Pages: 4045 - 4056
Abstract: ABSTRACTBuoyancy-restored modes inside neutron stars depend sensitively on both the microphysical (e.g. composition and entropy gradients) and macrophysical (e.g. stellar mass and radius) properties of the star. Asteroseismology efforts for g modes are therefore particularly promising avenues for recovering information concerning the nuclear equation of state. In this work, it is shown that the overall low-temperature g-space consists of multiple groups corresponding to different classes of equation of state (e.g. hadronic versus hybrid). This is in contrast to the case of pressure-driven modes, for example, which tend to follow a universal relation regardless of microphysical considerations. Using a wide library of currently viable equations of state, perturbations of static, stratified stars are calculated in general relativity to demonstrate in particular how g-space groupings can be classified according to the mean mass density, temperature, central speed of sound, and tidal deformability. Considering present and future observations regarding gravitational waves, accretion outbursts, quasi-periodic oscillations, and precursor flashes from gamma-ray bursts, it is shown how one might determine which group the g modes belong to.
PubDate: Mon, 25 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1101
Issue No: Vol. 513, No. 3 (2022)

• A mid-infrared study of superluminous supernovae

Authors: Sun L; Xiao L, Li G.
Pages: 4057 - 4073
Abstract: ABSTRACTWe present the mid-infrared (MIR) light curves (LC) of 10 superluminous supernovae (SLSNe) at z < 0.12 based on WISE data at 3.4 and 4.6 $\mu$m. Three of them, including PS15br, SN 2017ens, and SN 2017err show rebrightening which started at 200–400 d and ended at 600–1000 d, indicating the presence of dust. In four of the left seven SLSNe, dust emission was detected with monochromatic luminosities of $10^7\sim 10^8\, {\rm L}_\odot$ at epochs of 100–500 d based on MIR colours W1 − W2 ∼ 1. Among the three SLSNe which show rebrightening, we further analysed PS15br and SN 2017ens. We modelled the SEDs at 500–700 d, which gives dust temperatures of 600–1100 K, dust masses of $\gtrsim 10^{-2}\, {\rm M}_\odot$, and luminosities of $10^8\sim 10^9\, {\rm L}_\odot$. Considering the time delay and the huge amount of energy released, the emitting dust can hardly be pre-existing dust heated whether collisionally by shocks or radiatively by peak SLSN luminosity or shock emission. Instead, it can be newly formed dust additionally heated by the interaction of circumstellar medium, indicated by features in their spectra and slowly declining bolometric LCs. The dust masses appear to be ten times greater than those formed in normal core-collapse supernovae at similar epochs. Combining with the analysis of SN 2018bsz by Chen et al. (2021), we suggest that SLSNe have higher dust formation efficiency, although future observations are required to reach a final conclusion.
PubDate: Tue, 26 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1121
Issue No: Vol. 513, No. 3 (2022)

• Insight-HXMT measurements of the diffuse X-ray background

Authors: Huang R; Cui W, Liao J, et al.
Pages: 4074 - 4081
Abstract: ABSTRACTWe present an X-ray spectrum of the diffuse X-ray background (DXRB) between 1.5 and 120 keV, as measured with the Low-Energy Detector (LE) and the High-Energy Detector (HE) aboard the Insight-HXMT satellite, based on ’blank-sky’ observations. LE covers a nominal energy range of 1–15 keV and HE 20–250 keV, but calibration issues and data quality narrowed the energy range for this work. The LE background was directly measured with ‘blind’ detector modules, while the HE background was derived from Earth-occultation data. With the LE data alone, the measured DXRB spectrum can be well-described by a power law; fitting the LE and HE data jointly, however, a spectral cut-off must be introduced in the model to account for the measurements above 30 keV. Modelling the combined spectrum with a cut-off power law, the best-fitting photon index is 1.40, normalization 9.57 $\rm ph~cm^{-2}\,s^{-1}\,keV^{-1}\,sr^{-1}$ (at 1 keV), and cut-off energy 55 keV after correcting for the effects of the Earth albedo and atmospheric emission (which are significant in the HE band). Based on the best-fitting cut-off power law, we derived the spectral energy distribution (SED) of the DXRB. The shape of the SED is in general agreement with the published measurements, but the overall normalization is lower by varying amounts, except for the HEAO-1 result, with which our result is in good agreement.
PubDate: Mon, 25 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1129
Issue No: Vol. 513, No. 3 (2022)

• Plasma maser in the plasmasphere of HD 189733b

Authors: Zaitsev V; Shaposhnikov V.
Pages: 4082 - 4089
Abstract: ABSTRACTOn the example of the hot Jupiter HD 189733b, in whose magnetosphere the conditions for the ’operation’ of an electron–cyclotron maser are not fulfilled, an analysis of the plasma mechanism of radio emission generation is carried out. The purpose of the analysis is to highlight the range of parameters at which the realization of a plasma maser is possible, as well as to determine the frequency range of generated radio emission. The conditions under which the plasma maser is efficient enough to generate radiation with the intensity accessible for observation by the existing radio telescopes are also defined.
PubDate: Wed, 27 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1140
Issue No: Vol. 513, No. 3 (2022)

• Cross-correlations between mm-wave line-intensity mapping and weak-lensing
surveys: preliminary consideration of long-term prospects

Authors: Chung D.
Pages: 4090 - 4106
Abstract: ABSTRACTThe field of millimetre-wave line-intensity mapping (LIM) is seeing increased experimental activity with pathfinder surveys already deployed or deploying in the next few years, making spectroscopic measurements of unresolved atomic and molecular line emission tracing the large-scale structure of the Universe. The next decade will also see the Rubin Observatory Legacy Survey of Space and Time (LSST) undertake a photometric galaxy survey programme of unprecedented scope, including measurements of cosmic shear exploiting weak gravitational lensing (WL) of background galaxies to map projected large-scale structure. We consider prospects for detecting angular cross-power spectra between non-tomographic cosmic shear and mm-wave LIM surveys that measure emission from CO lines at z = 0.5–1. We forecast that once the LSST Year 10 WL data set is available, a future LIM experiment, conceivably deployed in the next 10–15 yr, would enable such a cross-correlation detection with an overall signal-to-noise ratio of 50, although the current pathfinder generation of CO/[C ii] surveys are more likely to achieve a marginal 2σ detection against an earlier-stage LSST WL data set. The signal has modest astrophysical constraining power yielding competitive constraints on cosmic molecular gas density at z ≲ 1, and degeneracies between astrophysical parameters and the intrinsic alignment amplitude mean that external information on either one could allow the cross-correlation analysis to significantly improve its constraints on the other.
PubDate: Wed, 27 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1142
Issue No: Vol. 513, No. 3 (2022)

• The chemo-dynamical groups of Galactic globular clusters

Authors: Callingham T; Cautun M, Deason A, et al.
Pages: 4107 - 4129
Abstract: ABSTRACTWe introduce a multicomponent chemo-dynamical method for splitting the Galactic population of globular clusters (GCs) into three distinct constituents: bulge, disc, and stellar halo. The latter is further decomposed into the individual large accretion events that built up the Galactic stellar halo: the Gaia–Enceladus–Sausage, Kraken and Sequoia structures, and the Sagittarius and Helmi streams. Our modelling is extensively tested using mock GC samples constructed from the auriga suite of hydrodynamical simulations of Milky Way (MW)-like galaxies. We find that, on average, a proportion of the accreted GCs cannot be associated with their true infall group and are left ungrouped, biasing our recovered population numbers to $\sim 80{{\ \rm per\ cent}}$ of their true value. Furthermore, the identified groups have a completeness and a purity of only $\sim 65{{\ \rm per\ cent}}$. This reflects the difficulty of the problem, a result of the large degree of overlap in energy-action space of the debris from past accretion events. We apply the method to the Galactic data to infer, in a statistically robust and easily quantifiable way, the GCs associated with each MW accretion event. The resulting groups’ population numbers of GCs, corrected for biases, are then used to infer the halo and stellar masses of the now defunct satellites that built up the halo of the MW.
PubDate: Fri, 29 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1145
Issue No: Vol. 513, No. 3 (2022)

• The Milky Way tomography with APOGEE: intrinsic density distribution and
structure of mono-abundance populations

Authors: Lian J; Zasowski G, Mackereth T, et al.
Pages: 4130 - 4151
Abstract: ABSTRACTThe spatial distribution of mono-abundance populations (MAPs, selected in [Fe/H] and [Mg/Fe]) reflect the chemical and structural evolution in a galaxy and impose strong constraints on galaxy formation models. In this paper, we use APOGEE data to derive the intrinsic density distribution of MAPs in the Milky Way, after carefully considering the survey selection function. We find that a single exponential profile is not a sufficient description of the Milky Way’s disc. Both the individual MAPs and the integrated disc exhibit a broken radial density distribution; densities are relatively constant with radius in the inner Galaxy and rapidly decrease beyond the break radius. We fit the intrinsic density distribution as a function of radius and vertical height with a 2D density model that considers both a broken radial profile and radial variation of scale height (i.e. flaring). There is a large variety of structural parameters between different MAPs, indicative of strong structure evolution of the Milky Way. One surprising result is that high-α MAPs show the strongest flaring. The young, solar-abundance MAPs present the shortest scale height and least flaring, suggesting recent and ongoing star formation confined to the disc plane. Finally we derive the intrinsic density distribution and corresponding structural parameters of the chemically defined thin and thick discs. The chemical thick and thin discs have local surface mass densities of 5.62 ± 0.08 and 15.69 ± 0.32 M⊙pc−2, respectively, suggesting a massive thick disc with a local surface mass density ratio between thick to thin disc of 36 per cent.
PubDate: Wed, 27 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1151
Issue No: Vol. 513, No. 3 (2022)

• A non-linear approach to predicting the amplitude and timing of the
sunspot area in cycle 25

Authors: Chowdhury P; Sarp V, Kilcik A, et al.
Pages: 4152 - 4158
Abstract: ABSTRACTThe sunspot cycle waxes and wanes over a period of about 11 years and modulates ‘space weather’. Therefore, predicting the maximum amplitude of the solar cycle is an important goal for both solar physics and space weather. It is clear nowadays that cyclic variations of the Sun are non-linear processes, and thus the above-mentioned goal is difficult to reach with accuracy, albeit several methods currently exist to forecast both long-term and short-term variations. Solar cycle 25 has recently started and knowing the strength and timing of maximum of this cycle in advance is essential. In this study, a non-linear prediction algorithm, non-linear empirical dynamical modelling (EDM), is used to forecast the maximum amplitude and timing of the sunspot area of this cycle. This technique was tested on the last solar cycle 24 (Sarp et al. 2018) and the results obtained are in good agreement with observed values. Our study unveils that the maximum amplitude of the sunspot area of the whole solar disc will be 1606.49 ± 412.78 millionths of the solar hemispheric area (m.s.h.) and is expected to occur around 2025 March. We found that the predicted maximum sunspot areas in the Northern and Southern hemispheres are 731.39 ± 192.7 and 764.89 ± 195.39 m.s.h., respectively, with probable times of maxima around 2023 September and 2024 August, respectively. These results indicate that the strength of the sunspot area in solar cycle 25 will be weaker than or comparable with that in solar cycle 24. Such results are discussed and compared with other recent forecasts.
PubDate: Tue, 17 May 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1162
Issue No: Vol. 513, No. 3 (2022)

• Prospects for multimessenger detection of binary neutron star mergers in
the fourth LIGO–Virgo–KAGRA observing run

Authors: Patricelli B; Bernardini M, Mapelli M, et al.
Pages: 4159 - 4168
Abstract: ABSTRACTThe joint detection of GW170817 and GRB 170817A opened the era of multimessenger astronomy with gravitational waves (GWs) and provided the first direct probe that at least some binary neutron star (BNS) mergers are progenitors of short gamma-ray bursts (S-GRBs). In the next years, we expect to have more multimessenger detections of BNS mergers, thanks to the increasing sensitivity of GW detectors. Here, we present a comprehensive study on the prospects for joint GW and electromagnetic observations of merging BNSs in the fourth Laser Interferometer Gravitational-wave Observatory (LIGO)–Virgo–Kamioka Gravitational Wave Detector (KAGRA) observing run with Fermi Gamma-ray Space Telescope (Fermi), Neil Gehrels Swift Observatory (Swift), INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL), and Space Variable Objects Monitor (SVOM). This work combines accurate population synthesis models with simulations of the expected GW signals and the associated S-GRBs, considering different assumptions about the gamma-ray burst (GRB) jet structure. We show that the expected rate of joint GW and electromagnetic detections could be up to ∼6 yr−1 when Fermi/Gamma-ray Burst Monitor (GBM) is considered. Future joint observations will help us to better constrain the association between BNS mergers and S-GRBs, as well as the geometry of the GRB jets.
PubDate: Thu, 28 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1167
Issue No: Vol. 513, No. 3 (2022)

• A unified model for the evolution of cataclysmic variables

Authors: Sarkar A; Tout C.
Pages: 4169 - 4177
Abstract: ABSTRACTWe give an updated version of the analytical equation of state used in the Cambridge stellar evolution code (stars) as a free to use open-source package that we have used to model cool white dwarfs (WDs) down to temperatures $\log _{10}(T_\mathrm{eff}/\mathrm{K})\, =\, 3$. With this update in the stars code, we model the secular evolution of cataclysmic variable (CV) stars using a double dynamo model wherein there is an interplay between two α − Ω dynamos, one in the convective envelope and the other at the boundary of a slowly rotating shrinking radiative core and the growing convective envelope. We confirm that this model provides a physical formalism for the interrupted magnetic braking paradigm. In addition, our model also provides a mechanism for extra angular momentum loss below the period gap. We construct the relative probability distribution of orbital periods Porb using the mass distribution of WDs in CVs and find that our model excellently reproduces the period gap and the observed period minimum spike in CV distribution. We also compare the evolutionary trajectories from our model with those of other empirical models and find agreement between the two. We also report good agreement between our modelled systems and observational data.
PubDate: Fri, 29 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1187
Issue No: Vol. 513, No. 3 (2022)

• Secular chaos in white dwarf planetary systems: origins of metal pollution
and short-period planetary companions

Authors: O’Connor C; Teyssandier J, Lai D.
Pages: 4178 - 4195
Abstract: ABSTRACTSecular oscillations in multiplanet systems can drive chaotic evolution of a small inner body through non-linear resonant perturbations. This ‘secular chaos’ readily pushes the inner body to an extreme eccentricity, triggering tidal interactions or collision with the central star. We present a numerical study of secular chaos in systems with two planets and test particles using the ring-averaging method, with emphasis on the relationship between the planets’ properties and the time-scale and efficiency of chaotic diffusion. We find that secular chaos can excite extreme eccentricities on time-scales spanning several orders of magnitude in a given system. We apply our results to the evolution of planetary systems around white dwarfs (WDs), specifically the tidal disruption and high-eccentricity migration of planetesimals and planets. We find that secular chaos in a planetesimal belt driven by large (≳10 M⊕), distant ($\gtrsim 10 \, \mathrm{au}$) planets can sustain metal accretion on to a WD over Gyr time-scales. We constrain the total mass of planetesimals initially present within the chaotic zone by requiring that the predicted mass delivery rate to the Roche limit be consistent with the observed metal accretion rates of WDs with atmospheric pollution throughout the cooling sequence. Based on the occurrence of long-period exoplanets and exo-asteroid belts, we conclude that secular chaos can be a significant (perhaps dominant) channel for polluting solitary WDs. Secular chaos can also produce short-period planets and planetesimals around WDs in concert with various circularization mechanisms. We discuss prospects for detecting exoplanets driving secular chaos around WDs using direct imaging and microlensing.
PubDate: Tue, 03 May 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1189
Issue No: Vol. 513, No. 3 (2022)

• The evolving properties of the corona of GRS 1915+105: a spectral-timing
perspective through variable-Comptonization modelling

Authors: García F; Karpouzas K, Méndez M, et al.
Pages: 4196 - 4207
Abstract: ABSTRACTThe inverse Compton process by which soft photons are up-scattered by hot electrons in a corona plays a fundamental role in shaping the X-ray spectra of black hole (BH) low-mass X-ray binaries (LMXBs), particularly in the hard and hard-intermediate states. In these states, the power-density spectra of these sources typically show Type-C low-frequency quasi-periodic oscillations (QPOs). Although several models have been proposed to explain the dynamical origin of their frequency, only a few of those models predict the spectral-timing radiative properties of the QPOs. Here, we study the physical and geometrical properties of the corona of the BH-LMXB GRS 1915+105 based on a large sample of observations available in the RXTE archive. We use a recently developed spectral-timing Comptonization model to fit simultaneously the energy-dependent fractional rms amplitude and phase-lag spectra of the Type-C QPO in 398 observations. For this, we include spectral information gathered from fitting a Comptonization model to the corresponding time-averaged spectra. We analyse the dependence of the physical and geometrical properties of the corona upon the QPO frequency and spectral state of the source, the latter characterized by the hardness ratio. We find consistent trends in the evolution of the corona size, temperature, and feedback (the fraction of the corona photons that impinge back on to the disc) that persist for roughly 15 yr. By correlating our observations with simultaneous radio-monitoring of the source at 15 GHz, we propose a scenario in which the disc–corona interactions connect with the launching mechanism of the radio jet in this source.
PubDate: Thu, 12 May 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1202
Issue No: Vol. 513, No. 3 (2022)

• The Quasar Feedback Survey: revealing the interplay of jets, winds, and
emission-line gas in type 2 quasars with radio polarization

Authors: Silpa S; Kharb P, Harrison C, et al.
Pages: 4208 - 4223
Abstract: ABSTRACTWe present results from a combined radio polarization and emission-line study of five type 2 quasars at z < 0.2 with the Karl G. Jansky Very Large Array (VLA) B-array at 5 GHz and Hubble Space Telescope (HST) [O iii] observations. These five sources are known to exhibit close association between radio structures and ionized gas morphology and kinematics. Four sources (J0945+1737, J1000+1242, J1356+1026, and J1430+1339) show polarization in the current data. J1010+1413 is the unpolarized source in our sample. We detect $0.5{-}1{{\ \rm per\ cent}}$ fractional polarization in the radio cores and a high fractional polarization ($10{-}30{{\ \rm per\ cent}}$) in the lobes of these sources. The morphological, spectral, and polarization properties suggest a jet origin for radio emission in J0945+1737, J1000+1242, J1010+1413, and J1430+1339 whereas the current data cannot fully discern the origin of radio emission (jet or wind) in J1356+1026. An anticorrelation between various polarized knots in the radio and [O iii] emission is observed in our sources, similar to that observed in some radio-loud AGN in the literature. This suggests that the radio emission is likely to be depolarized by the emission-line gas. By modelling the depolarization effects, we estimate the size of the emission-line gas clouds to be ∼(2.8 ± 1.7) × 10−5 parsec and the amount of thermal material mixed with the synchrotron plasma to be ∼(1.01 ± 0.08) × 106 M⊙ in the lobe of J0945+1737 (which exhibits the most prominent polarization signature in its lobe). The current work demonstrates that the interplay of jets/winds and emission-line gas is most likely responsible for the nature of radio outflows in radio-quiet AGN.
PubDate: Fri, 15 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1044
Issue No: Vol. 513, No. 3 (2022)

• Remnant masses of core collapse supernovae in the jittering jets explosion
mechanism

Authors: Shishkin D; Soker N.
Pages: 4224 - 4231
Abstract: ABSTRACTWe conduct one-dimensional (1D) stellar evolution simulations of non-rotating stars with initial masses in the range of $11\!-\!48 \, \mathrm{M}_{\odot }$ to the time of core collapse and, using a criterion on the specific angular momentum fluctuations in the inner convective zones, estimate the masses of the neutron star (NS) remnants according to the jittering jets explosion mechanism. From the 1D simulations, we find that several convective zones with specific angular momentum fluctuations of $j_{\rm {conv}} \gtrsim 2.5 \times 10^{15} {\, \rm cm}^2 {\, \rm s}^{-1}$ develop near the edge of the iron core in all models. For this condition for explosion, we find the NS remnant masses to be in the range of $1.3\!-\!1.8 \, \mathrm{M}_\odot$, while if we require twice as large values, i.e. $j_{\rm {conv}} \gtrsim 5 \times 10^{15} {\, \rm cm}^2 {\, \rm s}^{-1}$, we find the NS remnant masses to be in the range of $1.4\!-\!2.8 \, \mathrm{M}_\odot$ (the upper values here might form black holes). Note that in general, the formation of black holes in the jittering jets explosion mechanism requires a rapidly rotating pre-collapse core, while we simulate non-rotating stars.
PubDate: Tue, 19 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1075
Issue No: Vol. 513, No. 3 (2022)

• The SUNBIRD survey: the K-band luminosity functions of young massive
clusters in intensely star-forming galaxies

Authors: Randriamanakoto Z; Väisänen P, Ranaivomanana P, et al.
Pages: 4232 - 4256
Abstract: ABSTRACTStrongly star-forming galaxies are prolific in producing the young and most massive star clusters still forming today. This work investigates the star cluster luminosity functions (CLFs, dN/dL ∝ L−α) of 26 starburst and luminous infrared galaxies taken from the SUNBIRD survey. The targets were imaged using near-infrared K-band adaptive optics systems. Single power-law fits of the derived CLFs result in a slope α ranging between 1.53 and 2.41, with the median and average of 1.87 ± 0.23 and 1.93 ± 0.23, respectively. Possible biases such as blending effects and the choice of binning should only flatten the slope by no more than ∼0.15, especially for cases where the luminosity distance of the host galaxy is below 100 Mpc. Results from this follow-up study strengthen the conclusion from our previous work: the CLF slopes are shallower for strongly star-forming galaxies in comparison to those with less intense star formation activity. There is also a (mild) correlation between α and both the host galaxy’s star formation rate (SFR) and SFR density (ΣSFR), i.e. the CLF flattens with an increasing SFR and ΣSFR. Finally, we also find that CLFs on subgalactic scales associated with the nuclear regions of cluster-rich targets (N ≈ 300) have typically shallower slopes than the ones of the outer field by ∼0.5. Our analyses suggest that the extreme environments of strongly star-forming galaxies are likely to influence the cluster formation mechanisms and ultimately their physical properties.
PubDate: Wed, 27 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1103
Issue No: Vol. 513, No. 3 (2022)

• Constraints on the origins of hypervelocity stars: velocity distribution,
mergers, and star formation history

Authors: Generozov A; Perets H.
Pages: 4257 - 4266
Abstract: ABSTRACTIn recent years surveys have identified several dozen B stars in the Milky Way halo moving faster than the local escape speed. The origin of most of these hypervelocity stars (HVSs) is still poorly constrained. Here we show that the velocity distribution, and in particular the deficiency in >700 km s−1 HVSs is inconsistent with binary disruptions by the massive black hole (MBH) in the Galactic Centre. This conclusion holds in the full and empty loss-cone regime, and for secular instabilities in eccentric discs. Accounting for multiple close encounters between binaries and the MBH does not qualitatively change the results. Moreover, there is no observed counterpart population in the Galactic Centre that is consistent with the HVSs. The star formation history could be tuned explain the HVS velocity distribution, but this tuning would produce a mismatch with the observed HVS flight times. Frequent stellar collisions of the binary components due to interactions with the MBH do not significantly impact the velocity distribution in the Galactic halo. Such collisions, however, can leave observable remnants in the Galactic Centre, and potentially explain the origins of G2-like dust clouds.
PubDate: Fri, 29 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1108
Issue No: Vol. 513, No. 3 (2022)

• Magnetic reconnection and plasmoid formation in three-dimensional
accretion flows around black holes

Authors: Nathanail A; Mpisketzis V, Porth O, et al.
Pages: 4267 - 4277
Abstract: ABSTRACTMagnetic reconnection is thought to be one of the main energy-dissipation mechanisms fueling energy to the plasma in the vicinity of a black hole. Indeed, plasmoids formed through magnetic reconnection may play a key role in γ-ray, X-ray and near-infrared flares from the black hole at the centre of our galaxy, SgrA*. We report the results of 3D general-relativistic ideal and resistive magnetohydrodynamics simulations modelling magnetic reconnection in accretion flows around astrophysical black holes. As an important difference with similar works, our accretion discs have an initial dipolar magnetic-field configuration with loops of alternating polarity. We show that current sheets are formed and destroyed rapidly in the turbulent environment of black hole accretion. Plasmoids are formed from current sheets close to the event horizon, in a region of ∼2–15 gravitational radii. We further quantify the magnetic dissipation and the process of energy transfer to the plasmoids, reporting the reconnection rate, the relative current density with respect to the local magnetic field, and the size of the plasmoids. We find that plasmoids gain energy through reconnection and heat up to relativistic temperatures, with the largest ones being sufficiently energetic to leave the black hole near the polar regions. During their evolution, plasmoids are stretched and elongated, becoming disrupted when the shear is sufficiently large, although some plasmoids survive as well-distinguished structures at distances of ∼30–40 gravitational radii from the black hole. Finally, we find that in some cases the plasmoids acquire a super-Keplerian azimuthal velocity, as suggested by recent observations of flares from Sgr A*.
PubDate: Mon, 02 May 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1118
Issue No: Vol. 513, No. 3 (2022)

• The magnetic fields of β Coronae Borealis and the early F-star σ
Bootis

Authors: Seach J; Marsden S, Carter B, et al.
Pages: 4278 - 4294
Abstract: ABSTRACTThe study of magnetism in stars close to the transition from fossil to dynamo magnetic fields is important for understanding the nature of the stellar dynamo and dynamics of the outer atmosphere. We present surface magnetic maps for two stars that are located on opposite sides of the suspected transition zone: the chemically peculiar late A-star β Coronae Borealis (A9SrEuCr) and the early F-star σ Bootis (F3V). The large-scale magnetic field reconstructed at six epochs for β Coronae Borealis shows a complex fossil magnetic field, which is highly poloidal, and contains almost half the magnetic energy in higher multipoles (ℓ > 1). In contrast, the single epoch magnetic map for σ Bootis contains a simple surface magnetic topology that is mostly poloidal, and predominantly dipolar, and is consistent with observations of other mature late F-stars.
PubDate: Fri, 29 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1173
Issue No: Vol. 513, No. 3 (2022)

• TYC 2990-127-1: An Algol-type SB2 binary system of subgiant and red giant
with a probable ongoing mass-transfer

Authors: Kovalev M; Li Z, Zhang X, et al.
Pages: 4295 - 4307
Abstract: ABSTRACTWe present a study of the spectroscopic binary TYC 2990-127-1 from the LAMOST survey. We use full-spectrum fitting to derive radial velocities and spectral parameters. The high mass ratio indicates that the system underwent mass transfer in the past. We compute the orbital solution and find that it is a very close sub-giant/red giant pair on circular orbit, slightly inclined to the sky-plane. Fitting of the TESS photometrical data confirms this and suggests an inclination of i ∼ 39.8°. The light curve and spectrum around Hα show signs of irregular variability, which supports ongoing mass transfer. The binary evolution simulations suggest that the binary may experience non-conservative mass transfer with accretion efficiency 0.3, and the binary will enter into common envelope (CE) phase in the subsequent evolution. The remnant product after the ejection of CE may be a detached double helium white dwarf (He WD) or a merger.
PubDate: Fri, 29 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1177
Issue No: Vol. 513, No. 3 (2022)

• Rapidly alternating flux states of GX 339–4 during its 2021 outburst
captured by Insight–HXMT

Authors: Liu H; Jiang J, Zhang Z, et al.
Pages: 4308 - 4317
Abstract: ABSTRACTThe low-mass X-ray binary GX 339–4 entered a new outburst in 2021. At the end of the hard to soft transition of this outburst, Insight–HXMT found that the source rapidly alternated between low flux and high flux states on a time-scale of hours. Two high flux states lasted only for a period comparable to the orbital period of the observatory. Time-resolved spectral analysis shows that the sudden changes of flux are confined in the hard X-ray band (>4 keV). The variable non-thermal emission, including the power-law continuum from the corona and the reflected emission from the inner accretion disc, is responsible for the observed variability. The strength of the disc thermal emission and the inner radius of the accretion disc are consistent between the two flux states. Assuming the lamppost geometry, our best-fitting disc reflection models suggest a very low corona height (within 3 Rg) and there is no evidence of significant variation in the corona geometry either. The observed rapidly alternating flux states suggest that the intrinsic power of the corona must change during the state transition. We discuss possible mechanisms for the observed sudden changes in the coronal power of GX 339–4.
PubDate: Thu, 28 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1178
Issue No: Vol. 513, No. 3 (2022)

• A machine learning approach to correct for mass resolution effects in
simulated halo clustering statistics

Authors: Forero-Sánchez D; Chuang C, Rodríguez-Torres S, et al.
Pages: 4318 - 4331
Abstract: ABSTRACTThe increase in the observed volume in cosmological surveys imposes various challenges on simulation preparations. First, the volume of the simulations required increases proportionally to the observations. However, large-volume simulations are quickly becoming computationally intractable. Secondly, on-going and future large-volume survey are targeting smaller objects, e.g. emission line galaxies, compared to the earlier focus, i.e. luminous red galaxies. They require the simulations to have higher mass resolutions. In this work, we present a machine learning (ML) approach to calibrate the halo catalogue of a low-resolution (LR) simulation by training with a paired high-resolution (HR) simulation with the same background white noise, thus we can build the training data by matching HR haloes to LR haloes in a one-to-one fashion. After training, the calibrated LR halo catalogue reproduces the mass–clustering relation for mass down to 2.5 × 1011 h−1 M⊙ within 5 per cent at scales $k\lt 1\,h\, \rm Mpc^{-1}$. We validate the performance of different statistics including halo mass function, power spectrum, two-point correlation function, and bispectrum in both real and redshift space. Our approach generates HR-like halo catalogues (>200 particles per halo) from LR catalogues (>25 particles per halo) containing corrected halo masses for each object. This allows to bypass the computational burden of a large-volume real high-resolution simulation without much compromise in the mass resolution of the result. The cost of our ML approach (∼1 CPU-h) is negligible compared to the cost of a N-body simulation (e.g. millions of CPU-h), The required computing time is cut a factor of 8.
PubDate: Thu, 05 May 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac1239
Issue No: Vol. 513, No. 3 (2022)

• Low-frequency observations of giant pulses from ordinary pulsars

Authors: Kazantsev A; Basalaeva M.
Pages: 4332 - 4340
Abstract: ABSTRACTWe present the results of an investigation of the giant radio pulse (GRP) generation rate from five radio pulsars (B0301+19, B0950+08, B1112+50, B1133+16, and B1237+25) and anomalous intensity pulse generation rate from B0809+74. All data used were obtained with the Large Phased Array radio telescope at the Pushchino Radio Astronomy Observatory at 111 MHz from 2012 to 2021. In addition to the analysis of the rate of generation of bright pulses, we analyse the distribution of bright pulses in the phase of the pulsar period and search for clusters of bright pulses – several bright pulses emitted in adjacent pulsar periods. It is found that pulsars B0301+19, B1112+50, B1133+16, and B1237+25 demonstrate different generation rates and generation of clusters. Pulsar B1112+50 generates GRP clusters more often than the other pulsars studied. The longest cluster of GRPs containing four single pulses is detected from this pulsar. GRPs from the pulsars studied are distributed along the longitudes of the main components of the average pulses of these pulsars. This distribution is 1.5–2 times narrower than the phase distribution of non-giant pulses. It is found that the distance between the components of the average GRP profile and the distance between the components of the average non-giant profile differ substantially for pulsars with multicomponent average profiles.
PubDate: Wed, 18 May 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac473
Issue No: Vol. 513, No. 3 (2022)

• Six new compact triply eclipsing triples found with TESS

Authors: Rappaport S; Borkovits T, Gagliano R, et al.
Pages: 4341 - 4360
Abstract: ABSTRACTIn this work, we report the discovery and analysis of six new compact triply eclipsing triple star systems found with the TESS mission: TICs 37743815, 42565581, 54060695, 178010808, 242132789, and 456194776. All of these exhibit distinct third-body eclipses where the inner eclipsing binary (EB) occults the third (‘tertiary’) star, or vice versa. We utilized the TESS photometry, archival photometric data, and available archival spectral energy distribution curves (SED) to solve for the properties of all three stars, as well as many of the orbital elements. We describe in detail our SED fits, search of the archival data for the outer orbital period, and the final global photodynamical analyses. From these analyses, we find that all six systems are coplanar to within 0°−5°, and are viewed nearly edge on (i.e. within a couple of degrees). The outer orbital periods and eccentricities of the six systems are {Pout (days), e}: {68.7, 0.36}, {123, 0.16}, {60.7, 0.01}, {69.0, 0.29}, {41.5, 0.01}, {93.9, 0.29}, respectively, in the order the sources are listed above. The masses of all 12 EB stars were in the range of 0.7–1.8 M⊙ and were situated near the main sequence. By contrast, the masses and radii of the tertiary stars ranged from 1.5 to 2.3 M⊙ and 2.9 to 12 R⊙, respectively. We use this information to estimate the occurrence rate of compact flat triple systems..
PubDate: Thu, 07 Apr 2022 00:00:00 GMT
DOI: 10.1093/mnras/stac957
Issue No: Vol. 513, No. 3 (2022)

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