 Subjects -> ASTRONOMY (Total: 94 journals)
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- Measuring the Metallicity of Early-type Galaxies. I. Composite Region
- Authors: Yu-Zhong Wu
First page: 8
Abstract: We present the data of 9739 early-type galaxies (ETGs), cross-matching Galaxy Zoo 1 with our sample
selected from the catalog of the Sloan Digital Sky Survey Data Release 7 of MPA-JHU emission-line
measurements. We first investigate the divisor between ETGs with and without star formation (SF),
and find the best separator of W2–W3 = 2.0 is added. We explore the ETG sample by refusing a variety
of ionization sources, and derive 5376 ETGs with SF by utilizing a diagnostic tool of the division
line of W2–W3 = 2.0. We measure their metallicities with four abundance calibrators. We find that
our composite ETG sample has similar distributions of M * and star formation rate as star-forming
galaxies (SFGs) do, that most of them lie on the “main sequence,” and that our fit is a slightly
steeper slope than that derived in Renzini & Peng. Compared with the distributions between different
metallicities calibrated by four abundance indicators, we find that the Curti17 m...
Citation: The Astrophysical Journal Supplement Series
PubDate: 2021-01-07T00:00:00Z
DOI: 10.3847/1538-4365/abc0f1
Issue No: Vol. 252, No. 1 (2021)
- Analysis of Coronal Mass Ejection Flux Rope Signatures Using 3DCORE and
Approximate Bayesian
Computation- Authors: Andreas J. Weiss; Christian Möstl, Tanja Amerstorfer, Rachel L. Bailey, Martin A. Reiss, Jürgen Hinterreiter, Ute A. Amerstorfer, Maike Bauer
First page: 9
Abstract: We present a major update to the 3D coronal rope ejection (3DCORE) technique for modeling coronal
mass ejection flux ropes in conjunction with an approximate Bayesian computation (ABC) algorithm
that is used for fitting the model to in situ magnetic field measurements. The model assumes an
empirically motivated torus-like flux rope structure that expands self-similarly within the
heliosphere, is influenced by a simplified interaction with the solar wind environment, and carries
along an embedded analytical magnetic field. The improved 3DCORE implementation allows us to
generate extremely large ensemble simulations that we then use to find global best-fit model
parameters using an ABC sequential Monte Carlo algorithm. The usage of this algorithm, under some
basic assumptions on the uncertainty of the magnetic field measurements, allows us to furthermore
generate estimates on the uncertainty of model parameters using only a single in situ observation.
We apply our model to synthet...
Citation: The Astrophysical Journal Supplement Series
PubDate: 2021-01-13T00:00:00Z
DOI: 10.3847/1538-4365/abc9bd
Issue No: Vol. 252, No. 1 (2021)
- The Spectrum and Term Analysis of Singly Ionized Manganese
- Authors: Florence S. Liggins; Juliet C. Pickering, Gillian Nave, Jacob W. Ward, W.-Ü L. Tchang-Brillet
First page: 10
Abstract: An extensive analysis of the Mn spectrum was carried out using high-resolution Fourier transform
(FT) and grating spectroscopy of Mn–Ne and Mn–Ar hollow cathode discharge sources, over the range
82–5500 nm (1820–121,728 cm −1 ). Spectral wavelengths for a total of 6019 Mn ii lines have been
measured, of which 1345 are obtained through FT spectroscopy. These wavelengths are given to at
least an order of magnitude lower uncertainty than previous measurements. These lines were used to
identify 6256 Mn ii transitions and improve the values of 505 previously published energy levels
with typical uncertainties of a few thousandths of a cm −1 , representing an order-of-magnitude
reduction in uncertainty. We have verified and improved an additional 57 Mn ii energy levels,
previously established through observation of stellar spectra alone, using our FT spectra. In
addition, 52 new energy level va...
Citation: The Astrophysical Journal Supplement Series
PubDate: 2021-01-13T00:00:00Z
DOI: 10.3847/1538-4365/abc75f
Issue No: Vol. 252, No. 1 (2021)
- Solar Bayesian Analysis Toolkit—A New Markov Chain Monte Carlo IDL Code
for Bayesian Parameter
Inference- Authors: Sergey A. Anfinogentov; Valery M. Nakariakov, David J. Pascoe, Christopher R. Goddard
First page: 11
Abstract: We present the Solar Bayesian Analysis Toolkit (SoBAT), which is a new easy to use tool for Bayesian
analysis of observational data, including parameter inference and model comparison. SoBAT is aimed
(but not limited) to be used for the analysis of solar observational data. We describe a new IDL
code designed to facilitate the comparison of a user-supplied model with data. Bayesian inference
allows prior information to be taken into account. The use of Markov Chain Monte Carlo sampling
allows efficient exploration of large parameter spaces and provides reliable estimation of model
parameters and their uncertainties. The Bayesian evidence for different models can be used for
quantitative comparison. The code is tested to demonstrate its ability to accurately recover a
variety of parameter probability distributions. Its application to practical problems is
demonstrated using studies of the structure and oscillation of coronal loops.
Citation: The Astrophysical Journal Supplement Series
PubDate: 2021-01-13T00:00:00Z
DOI: 10.3847/1538-4365/abc5c1
Issue No: Vol. 252, No. 1 (2021)
- powderday : Dust Radiative Transfer for Galaxy Simulations
- Authors: Desika Narayanan; Matthew J. Turk, Thomas Robitaille, Ashley J. Kelly, B. Connor McClellan, Ray S Sharma, Prerak Garg, Matthew Abruzzo, Ena Choi, Charlie Conroy, Benjamin D. Johnson, Benjamin Kimock, Qi Li, Christopher C. Lovell, Sidney Lower, George C. Privon, Jonathan Roberts, Snigdaa Sethuram, Gregory F. Snyder, Robert Thompson, John H. Wise
First page: 12
Abstract: We present powderday (available at https://github.com/dnarayanan/powderday
[https://github.com/dnarayanan/powderday] ), a flexible, fast, open-source dust radiative transfer
package designed to interface with both idealized and cosmological galaxy formation simulations.
powderday builds on fsps stellar population synthesis models, and hyperion dust radiative transfer,
and employs yt to interface between different software packages. We include our stellar population
synthesis modeling on the fly, allowing significant flexibility in the assumed stellar physics and
nebular line emission. The dust content follows either simple observationally motivated
prescriptions (i.e., constant dust-to-metals ratios, or dust-to-gas ratios that vary with
metallicity), direct modeling from galaxy formation simulations that include dust physics, as well
as a novel ...
Citation: The Astrophysical Journal Supplement Series
PubDate: 2021-01-13T00:00:00Z
DOI: 10.3847/1538-4365/abc487
Issue No: Vol. 252, No. 1 (2021)
- OH Evolution in Molecular Clouds
- Authors: Ningyu Tang; Di Li, Nannan Yue, Pei Zuo, Tie Liu, Gan Luo, Longfei Chen, Sheng-Li Qin, Yuefang Wu, Carl Heiles
First page: 1
Abstract: We have conducted a OH 18 cm survey toward 141 molecular clouds in various environments, including
33 optical dark clouds, 98 Planck Galactic cold clumps (PGCCs), and 10 Spitzer dark clouds with the
Arecibo telescope. The deviations from local thermal equilibrium are common for intensity ratios of
both OH main lines and satellite lines. Line intensity of OH 1667 MHz is found to correlate linearly
with visual extinction ##IMG## [http://ej.iop.org/images/0067-0049/252/1/1/apjsabca94ieqn1.gif]
{${A}_{{\rm{V}}}$} when ##IMG## [http://ej.iop.org/images/0067-0049/252/1/1/apjsabca94ieqn2.gif]
{${A}_{{\rm{V}}}$} is less than 3 mag. It was converted into OH column density by adopting the
excitation temperature derived from Monte Carlo simulations with 1 σ uncertainty. The relationship
between OH abundance X (OH) relative to H 2 and ##IMG##
[http://ej.iop.org/images/0067-0049/252/1/1/a...] {${A}_{{\rm{V}}}$}
Citation: The Astrophysical Journal Supplement Series
PubDate: 2020-12-17T00:00:00Z
DOI: 10.3847/1538-4365/abca94
Issue No: Vol. 252, No. 1 (2020)
- The NANOGrav 12.5 yr Data Set: Observations and Narrowband Timing of 47
Millisecond Pulsars- Authors: Md F. Alam; Zaven Arzoumanian, Paul T. Baker, Harsha Blumer, Keith E. Bohler, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Keeisi Caballero, Richard S. Camuccio, Rachel L. Chamberlain, Shami Chatterjee, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Megan E. DeCesar, Paul B. Demorest, Timothy Dolch, Justin A. Ellis, Robert D. Ferdman, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Yhamil Garcia, Nathan Garver-Daniels, Peter A. Gentile, Deborah C. Good, Jordan A. Gusdorff, Daniel Halmrast, Jeffrey S. Hazboun, Kristina Islo, Ross J. Jennings, Cody Jessup, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Joey Shapiro Key, Michael T. Lam, T. Joseph W. Lazio, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Dustin R. Madison, Kaleb Maraccini, Maura A. McLaughlin, Chiara M. F. Mingarelli, Cherry Ng, Benjamin M. X. Nguyen, David J. Nice, Timothy T. Pennucci, Nihan S. Pol, Joshua Ramette, Scott M. Ransom, Paul S. Ray, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Renée Spiewak, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Joseph K. Swiggum, Stephen R. Taylor, Michael Tripepi, Michele Vallisneri, Sarah J. Vigeland, Caitlin A. Witt Weiwei Zhu (The NANOGrav Collaboration)
First page: 4
Abstract: We present time-of-arrival (TOA) measurements and timing models of 47 millisecond pulsars observed
from 2004 to 2017 at the Arecibo Observatory and the Green Bank Telescope by the North American
Nanohertz Observatory for Gravitational Waves (NANOGrav). The observing cadence was three to four
weeks for most pulsars over most of this time span, with weekly observations of six sources. These
data were collected for use in low-frequency gravitational wave searches and for other astrophysical
purposes. We detail our observational methods and present a set of TOA measurements, based on
“narrowband” analysis, in which many TOAs are calculated within narrow radio-frequency bands for
data collected simultaneously across a wide bandwidth. A separate set of “wideband” TOAs will be
presented in a companion paper. We detail a number of methodological changes, compared to our
previous work, which yield a cleaner and more uniformly processed data set. Our timing models
include several new astr...
Citation: The Astrophysical Journal Supplement Series
PubDate: 2020-12-21T00:00:00Z
DOI: 10.3847/1538-4365/abc6a0
Issue No: Vol. 252, No. 1 (2020)
- The NANOGrav 12.5 yr Data Set: Wideband Timing of 47 Millisecond Pulsars
- Authors: Md F. Alam; Zaven Arzoumanian, Paul T. Baker, Harsha Blumer, Keith E. Bohler, Adam Brazier, Paul R. Brook, Sarah Burke-Spolaor, Keeisi Caballero, Richard S. Camuccio, Rachel L. Chamberlain, Shami Chatterjee, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Megan E. DeCesar, Paul B. Demorest, Timothy Dolch, Justin A. Ellis, Robert D. Ferdman, Elizabeth C. Ferrara, William Fiore, Emmanuel Fonseca, Yhamil Garcia, Nathan Garver-Daniels, Peter A. Gentile, Deborah C. Good, Jordan A. Gusdorff, Daniel Halmrast, Jeffrey S. Hazboun, Kristina Islo, Ross J. Jennings, Cody Jessup, Megan L. Jones, Andrew R. Kaiser, David L. Kaplan, Luke Zoltan Kelley, Joey Shapiro Key, Michael T. Lam, T. Joseph W. Lazio, Duncan R. Lorimer, Jing Luo, Ryan S. Lynch, Dustin R. Madison, Kaleb Maraccini, Maura A. McLaughlin, Chiara M. F. Mingarelli, Cherry Ng, Benjamin M. X. Nguyen, David J. Nice, Timothy T. Pennucci, Nihan S. Pol, Joshua Ramette, Scott M. Ransom, Paul S. Ray, Brent J. Shapiro-Albert, Xavier Siemens, Joseph Simon, Renée Spiewak, Ingrid H. Stairs, Daniel R. Stinebring, Kevin Stovall, Joseph K. Swiggum, Stephen R. Taylor, Michael Tripepi, Michele Vallisneri, Sarah J. Vigeland, Caitlin A. Witt Weiwei Zhu (The NANOGrav Collaboration)
First page: 5
Abstract: We present a new analysis of the profile data from the 47 millisecond pulsars comprising the 12.5 yr
data set of the North American Nanohertz Observatory for Gravitational Waves, which is presented in
a parallel paper (Alam et al., hereafter NG12.5). Our reprocessing is performed using “wideband”
timing methods, which use frequency-dependent template profiles, simultaneous time-of-arrival (TOA)
and dispersion measure (DM) measurements from broadband observations, and novel analysis techniques.
In particular, the wideband DM measurements are used to constrain the DM portion of the timing
model. We compare the ensemble timing results to those in NG12.5 by examining the timing residuals,
timing models, and noise-model components. There is a remarkable level of agreement across all
metrics considered. Our best-timed pulsars produce encouragingly similar results to those from
NG12.5. In certain cases, such as high-DM pulsars with profile broadening or sources that are weak
and scinti...
Citation: The Astrophysical Journal Supplement Series
PubDate: 2020-12-21T00:00:00Z
DOI: 10.3847/1538-4365/abc6a1
Issue No: Vol. 252, No. 1 (2020)
- Measuring Solar Differential Rotation with an Iterative Phase Correlation
Method- Authors: Zdeněk Hrazdíra; Miloslav Druckmüller, Shadia Habbal
First page: 6
Abstract: A reliable inference of the differential rotation rate of the solar photosphere is essential for
models of the solar interior. The work presented here is based on a novel iterative phase
correlation technique, which relies on the measurement of the local shift, at the central meridian,
between two images separated by a given time interval. Consequently, it does not require any
specific reference features, such as sunspots or supergranules, nor extended observations spanning
several months. The reliability of the method is demonstrated by applying it to high spatial and
temporal resolution continuum images of the solar photosphere, at 6173 Å, acquired by the Solar
Dynamics Observatory Helioseismic and Magnetic Imager over one complete Carrington rotation. The
data selected covers the time period of 2020 January 1 to February 2. The method was applied to one
day, and to the full time interval. The differential rotation rate derived using this
feature-independent technique yields v...
Citation: The Astrophysical Journal Supplement Series
PubDate: 2020-12-23T00:00:00Z
DOI: 10.3847/1538-4365/abc702
Issue No: Vol. 252, No. 1 (2020)
- Proton and Hydrogen Transport through Hydrogen Environments: Ionization
and Stripping- Authors: N. D. Cariatore; D. R. Schultz
First page: 7
Abstract: Data are presented over a wide range of impact energies describing the ionization or stripping
probability, projectile energy loss, and ejected electron and recoiling target energies and angles
for proton and hydrogen passage through hydrogen astrophysical environments. These kinematic and
reaction data are tabulated at three levels of detail for use in heavy-particle (H + , H) and
secondary-electron transport simulations: (1) the integral scattering cross section and average
values of the distributions of energy and angle of the particles, (2) the singly differential cross
sections as a function of particle energy and angle, and (3) a subset of the many possible doubly
differential cross sections as functions of the particle energy and angle chosen to be most relevant
to transport simulations.
Citation: The Astrophysical Journal Supplement Series
PubDate: 2020-12-23T00:00:00Z
DOI: 10.3847/1538-4365/abc2c7
Issue No: Vol. 252, No. 1 (2020)
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