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  Subjects -> BUSINESS AND ECONOMICS (Total: 3075 journals)
    - ACCOUNTING (89 journals)
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    - BUSINESS AND ECONOMICS (1154 journals)
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BUSINESS AND ECONOMICS (1154 journals)                  1 2 3 4 5 6 | Last

Showing 1 - 200 of 1566 Journals sorted alphabetically
4OR: A Quarterly Journal of Operations Research     Hybrid Journal   (Followers: 9)
Abacus     Hybrid Journal   (Followers: 11)
Accounting Forum     Hybrid Journal   (Followers: 22)
Acta Amazonica     Open Access   (Followers: 3)
Acta Commercii     Open Access   (Followers: 2)
Acta Oeconomica     Full-text available via subscription   (Followers: 2)
Acta Scientiarum. Human and Social Sciences     Open Access   (Followers: 4)
Acta Universitatis Danubius. Œconomica     Open Access  
Acta Universitatis Nicolai Copernici Zarządzanie     Open Access   (Followers: 3)
AD-minister     Open Access   (Followers: 2)
ADR Bulletin     Open Access   (Followers: 5)
Advances in Developing Human Resources     Hybrid Journal   (Followers: 21)
Advances in Economics and Business     Open Access   (Followers: 12)
AfricaGrowth Agenda     Full-text available via subscription   (Followers: 1)
African Affairs     Hybrid Journal   (Followers: 57)
African Development Review     Hybrid Journal   (Followers: 34)
African Journal of Business and Economic Research     Full-text available via subscription   (Followers: 1)
African Journal of Business Ethics     Open Access   (Followers: 7)
African Review of Economics and Finance     Open Access   (Followers: 3)
Afro-Asian Journal of Finance and Accounting     Hybrid Journal   (Followers: 6)
Afyon Kocatepe Üniversitesi İktisadi ve İdari Bilimler Fakültesi Dergisi     Open Access   (Followers: 3)
Agronomy     Open Access   (Followers: 11)
Akademika : Journal of Southeast Asia Social Sciences and Humanities     Open Access   (Followers: 4)
Alphanumeric Journal : The Journal of Operations Research, Statistics, Econometrics and Management Information Systems     Open Access   (Followers: 4)
American Economic Journal : Applied Economics     Full-text available via subscription   (Followers: 124)
American Economic Journal : Economic Policy     Full-text available via subscription   (Followers: 94)
American Journal of Business     Hybrid Journal   (Followers: 14)
American Journal of Business and Management     Open Access   (Followers: 50)
American Journal of Business Education     Open Access   (Followers: 10)
American Journal of Economics and Business Administration     Open Access   (Followers: 22)
American Journal of Economics and Sociology     Hybrid Journal   (Followers: 27)
American Journal of Evaluation     Hybrid Journal   (Followers: 12)
American Journal of Finance and Accounting     Hybrid Journal   (Followers: 16)
American Journal of Health Economics     Full-text available via subscription   (Followers: 12)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
American Journal of Medical Quality     Hybrid Journal   (Followers: 7)
American Law and Economics Review     Hybrid Journal   (Followers: 26)
ANALES de la Universidad Central del Ecuador     Open Access   (Followers: 1)
Annales de l'Institut Henri Poincare (C) Non Linear Analysis     Full-text available via subscription   (Followers: 1)
Annals in Social Responsibility     Full-text available via subscription  
Annals of Finance     Hybrid Journal   (Followers: 26)
Annals of Operations Research     Hybrid Journal   (Followers: 8)
Annual Review of Economics     Full-text available via subscription   (Followers: 29)
Applied Developmental Science     Hybrid Journal   (Followers: 4)
Applied Economics     Hybrid Journal   (Followers: 44)
Applied Economics Letters     Hybrid Journal   (Followers: 28)
Applied Economics Quarterly     Full-text available via subscription   (Followers: 10)
Applied Financial Economics     Hybrid Journal   (Followers: 21)
Applied Mathematical Finance     Hybrid Journal   (Followers: 6)
Applied Stochastic Models in Business and Industry     Hybrid Journal   (Followers: 5)
Apuntes Universitarios     Open Access   (Followers: 1)
Arab Economic and Business Journal     Open Access   (Followers: 3)
Archives of Business Research     Open Access   (Followers: 4)
Arena Journal     Full-text available via subscription   (Followers: 1)
Argomenti. Rivista di economia, cultura e ricerca sociale     Open Access   (Followers: 2)
ASEAN Economic Bulletin     Full-text available via subscription   (Followers: 5)
Asia Pacific Business Review     Hybrid Journal   (Followers: 5)
Asia Pacific Journal of Human Resources     Hybrid Journal   (Followers: 309)
Asia Pacific Viewpoint     Hybrid Journal  
Asia-Pacific Journal of Business Administration     Hybrid Journal   (Followers: 3)
Asia-Pacific Journal of Operational Research     Hybrid Journal   (Followers: 3)
Asian Business Review     Open Access   (Followers: 2)
Asian Case Research Journal     Hybrid Journal   (Followers: 1)
Asian Development Review     Open Access   (Followers: 14)
Asian Economic Journal     Hybrid Journal   (Followers: 6)
Asian Economic Papers     Hybrid Journal   (Followers: 7)
Asian Economic Policy Review     Hybrid Journal   (Followers: 3)
Asian Journal of Accounting and Governance     Open Access   (Followers: 3)
Asian Journal of Business Ethics     Hybrid Journal   (Followers: 7)
Asian Journal of Social Sciences and Management Studies     Open Access   (Followers: 6)
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 9)
Asian-pacific Economic Literature     Hybrid Journal   (Followers: 5)
AStA Wirtschafts- und Sozialstatistisches Archiv     Hybrid Journal   (Followers: 5)
Atlantic Economic Journal     Hybrid Journal   (Followers: 14)
Australasian Journal of Regional Studies, The     Full-text available via subscription   (Followers: 2)
Australian Cottongrower, The     Full-text available via subscription   (Followers: 1)
Australian Economic Papers     Hybrid Journal   (Followers: 16)
Australian Economic Review     Hybrid Journal   (Followers: 7)
Australian Journal of Maritime and Ocean Affairs     Hybrid Journal   (Followers: 11)
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Baltic Journal of Real Estate Economics and Construction Management     Open Access   (Followers: 1)
Banks in Insurance Report     Hybrid Journal   (Followers: 1)
BBR - Brazilian Business Review     Open Access   (Followers: 5)
Benchmarking : An International Journal     Hybrid Journal   (Followers: 11)
BER : Consumer Confidence Survey     Full-text available via subscription   (Followers: 4)
BER : Economic Prospects : An Executive Summary     Full-text available via subscription  
BER : Economic Prospects : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Intermediate Goods Industries Survey     Full-text available via subscription   (Followers: 1)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Building and Construction : An Executive Summary     Full-text available via subscription   (Followers: 4)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Trends : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Wholesale Sector Survey     Full-text available via subscription   (Followers: 1)
Berkeley Business Law Journal     Free   (Followers: 11)
Bio-based and Applied Economics     Open Access   (Followers: 1)
Biodegradation     Hybrid Journal   (Followers: 1)
Biology Direct     Open Access   (Followers: 7)
Black Enterprise     Full-text available via subscription  
Board & Administrator for Administrators only     Hybrid Journal  
Border Crossing : Transnational Working Papers     Open Access   (Followers: 2)
Briefings in Real Estate Finance     Hybrid Journal   (Followers: 5)
British Journal of Industrial Relations     Hybrid Journal   (Followers: 30)
Brookings Papers on Economic Activity     Open Access   (Followers: 46)
Brookings Trade Forum     Full-text available via subscription   (Followers: 3)
BRQ Business Research Quarterly     Open Access   (Followers: 2)
Building Sustainable Legacies : The New Frontier Of Societal Value Co-Creation     Full-text available via subscription   (Followers: 1)
Bulletin of Economic Research     Hybrid Journal   (Followers: 16)
Bulletin of Geography. Socio-economic Series     Open Access   (Followers: 6)
Bulletin of Indonesian Economic Studies     Hybrid Journal   (Followers: 3)
Bulletin of the Dnipropetrovsk University. Series : Management of Innovations     Open Access   (Followers: 1)
Business & Entrepreneurship Journal     Open Access   (Followers: 15)
Business & Information Systems Engineering     Hybrid Journal   (Followers: 5)
Business & Society     Hybrid Journal   (Followers: 9)
Business : Theory and Practice / Verslas : Teorija ir Praktika     Open Access   (Followers: 1)
Business and Economic Horizons     Open Access   (Followers: 2)
Business and Economic Research     Open Access   (Followers: 5)
Business and Management Horizons     Open Access   (Followers: 11)
Business and Management Research     Open Access   (Followers: 16)
Business and Management Studies     Open Access   (Followers: 7)
Business and Politics     Hybrid Journal   (Followers: 6)
Business and Professional Communication Quarterly     Hybrid Journal   (Followers: 7)
Business and Society Review     Hybrid Journal   (Followers: 5)
Business Economics     Hybrid Journal   (Followers: 6)
Business Ethics: A European Review     Hybrid Journal   (Followers: 16)
Business Horizons     Hybrid Journal   (Followers: 9)
Business Information Review     Hybrid Journal   (Followers: 13)
Business Management and Strategy     Open Access   (Followers: 39)
Business Research     Hybrid Journal   (Followers: 1)
Business Strategy and the Environment     Hybrid Journal   (Followers: 11)
Business Strategy Review     Hybrid Journal   (Followers: 6)
Business Strategy Series     Hybrid Journal   (Followers: 5)
Business Systems & Economics     Open Access   (Followers: 1)
Business Systems Research Journal     Open Access   (Followers: 4)
Business, Management and Education     Open Access   (Followers: 16)
Business, Peace and Sustainable Development     Full-text available via subscription   (Followers: 3)
Bustan     Hybrid Journal   (Followers: 1)
Cadernos EBAPE.BR     Open Access   (Followers: 1)
Cambridge Journal of Economics     Hybrid Journal   (Followers: 55)
Cambridge Journal of Regions, Economy and Society     Hybrid Journal   (Followers: 9)
Canadian Journal of Administrative Sciences / Revue Canadienne des Sciences de l Administration     Hybrid Journal   (Followers: 1)
Canadian Journal of Economics/Revue Canadienne d`Economique     Hybrid Journal   (Followers: 25)
Canadian journal of nonprofit and social economy research     Open Access   (Followers: 2)
Capitalism and Society     Hybrid Journal   (Followers: 2)
Capitalism Nature Socialism     Hybrid Journal   (Followers: 11)
Case Studies in Business and Management     Open Access   (Followers: 8)
CBU International Conference Proceedings     Open Access   (Followers: 1)
Central European Business Review     Open Access   (Followers: 1)
Central European Journal of Operations Research     Hybrid Journal   (Followers: 5)
Central European Journal of Public Policy     Open Access   (Followers: 1)
CESifo Economic Studies     Hybrid Journal   (Followers: 15)
Chain Reaction     Full-text available via subscription   (Followers: 1)
Challenge     Full-text available via subscription   (Followers: 4)
China & World Economy     Hybrid Journal   (Followers: 15)
China : An International Journal     Full-text available via subscription   (Followers: 17)
China Economic Journal: The Official Journal of the China Center for Economic Research (CCER) at Peking University     Hybrid Journal   (Followers: 10)
China Economic Review     Hybrid Journal   (Followers: 10)
China Finance Review International     Hybrid Journal   (Followers: 5)
China Nonprofit Review     Hybrid Journal   (Followers: 3)
China perspectives     Open Access   (Followers: 11)
Chinese Economy     Full-text available via subscription  
Ciência & Saúde Coletiva     Open Access   (Followers: 2)
CLIO América     Open Access   (Followers: 1)
Cliometrica     Hybrid Journal   (Followers: 1)
COEPTUM     Open Access  
Community Development Journal     Hybrid Journal   (Followers: 23)
Compensation & Benefits Review     Hybrid Journal   (Followers: 6)
Competition & Change     Hybrid Journal   (Followers: 10)
Competitive Intelligence Review     Hybrid Journal   (Followers: 2)
Competitiveness Review : An International Business Journal incorporating Journal of Global Competitiveness     Hybrid Journal   (Followers: 5)
Computational Economics     Hybrid Journal   (Followers: 9)
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computer Law & Security Report     Hybrid Journal   (Followers: 15)
Computers & Operations Research     Hybrid Journal   (Followers: 10)
Construction Innovation: Information, Process, Management     Hybrid Journal   (Followers: 14)
Contemporary Wales     Full-text available via subscription   (Followers: 3)
Contextus - Revista Contemporânea de Economia e Gestão     Open Access   (Followers: 1)
Contributions to Political Economy     Hybrid Journal   (Followers: 6)
Corporate Communications An International Journal     Hybrid Journal   (Followers: 4)
Corporate Philanthropy Report     Hybrid Journal   (Followers: 2)
Corporate Reputation Review     Hybrid Journal   (Followers: 5)
Creative and Knowledge Society     Open Access   (Followers: 10)
Creative Industries Journal     Hybrid Journal   (Followers: 8)
CRIS - Bulletin of the Centre for Research and Interdisciplinary Study     Open Access   (Followers: 1)
Crossing the Border : International Journal of Interdisciplinary Studies     Open Access   (Followers: 4)
Cuadernos de Administración (Universidad del Valle)     Open Access   (Followers: 1)
Cuadernos de Economía     Open Access   (Followers: 1)
Cuadernos de Economia - Latin American Journal of Economics     Open Access   (Followers: 1)
Cuadernos de Estudios Empresariales     Open Access   (Followers: 1)
Current Opinion in Creativity, Innovation and Entrepreneurship     Open Access   (Followers: 8)
De Economist     Hybrid Journal   (Followers: 12)
Decision Analysis     Full-text available via subscription   (Followers: 8)
Decision Sciences     Hybrid Journal   (Followers: 15)
Decision Support Systems     Hybrid Journal   (Followers: 15)
Defence and Peace Economics     Hybrid Journal   (Followers: 16)
der markt     Hybrid Journal   (Followers: 1)
Desenvolvimento em Questão     Open Access  

        1 2 3 4 5 6 | Last

Journal Cover Asian-pacific Economic Literature
  [SJR: 0.168]   [H-I: 15]   [5 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0818-9935 - ISSN (Online) 1467-8411
   Published by John Wiley and Sons Homepage  [1616 journals]
  • Surface magnetism of cool stars
    • Authors: O. Kochukhov; P. Petit, K. G. Strassmeier, T. A. Carroll, R. Fares, C. P. Folsom, S. V. Jeffers, H. Korhonen, J. D. Monnier, J. Morin, L. Rosén, R. M. Roettenbacher, D. Shulyak
      Abstract: Magnetic fields are essential ingredients of many physical processes in the interiors and envelopes of cool stars. Yet their direct detection and characterization is notoriously difficult, requiring high-quality observations and advanced analysis techniques. Significant progress has been recently achieved by several types of direct magnetic field studies on the surfaces of cool, active stars. In particular, complementary techniques of field topology mapping with polarization data and total magnetic flux measurements from intensity spectra have been systematically applied to different classes of active stars, leading to interesting and occasionally controversial results. In this paper, we summarize the current status of direct magnetic field studies of cool stars and investigations of surface inhomogeneities caused by the field, based on the material presented at the Cool Stars 19 splinter session.
      PubDate: 2017-03-17T02:25:33.164889-05:
      DOI: 10.1002/asna.201713310
  • X-ray studies of solar system objects: Past, present, and the next decade
    • Authors: G. Branduardi-Raymont
      Abstract: This paper presents an overview of the remarkable progress that X-ray studies of solar system objects have delivered over the past three decades, covering research that encompasses remote observations with XMM-Newton and Chandra, in situ measurements by planetary missions, and models of solar wind propagation from 1 AU. The future of X-ray exploration of the solar system in the next decade is bright, counting on the continuing excellent imaging and spectral performance of XMM-Newton instruments, which is most effective when combined with the outstanding spatial resolution of Chandra and in particular while planetary missions are making in situ measurements of solar wind and local conditions.
      PubDate: 2017-03-16T01:38:12.078501-05:
      DOI: 10.1002/asna.201713329
  • A decade of warm hot intergalactic medium searches: Where do we stand and
           where do we go?
    • Authors: F. Nicastro; Y. Krongold, S. Mathur, M. Elvis
      Abstract: In this article, we first review the past decade of efforts in detecting the missing baryons in the warm hot intergalactic medium and summarize the current state of the art by updating the baryon census and physical state of the detected baryons in the local Universe. We then describe observational strategies that should enable a significant step forward in the next decade, while waiting for the step-up in quality offered by future missions. In particular, we design a multi-megasecond and multiple cycle XMM-Newton legacy' program (which we name the Ultimate Roaming Baryon Exploration, or URBE), aimed at securing detections of the peaks in the density distribution of the Universe of missing baryons over their entire predicted range of temperatures.
      PubDate: 2017-03-16T01:37:47.143657-05:
      DOI: 10.1002/asna.201713343
  • eROSITA on SRG
    • Authors: P. Predehl
      Abstract: eROSITA (extended ROentgen Survey with an Imaging Telescope Array) is the core instrument on the Russian–German Spectrum-Roentgen-Gamma (SRG) mission, which is currently scheduled for launch in late 2017. eROSITA will perform a deep survey of the entire X-ray sky. In the soft band (0.5–2 keV), it will be about 30 times more sensitive than ROSAT, while in the hard band (2–8 keV) it will provide the first ever true imaging survey of the sky. The design driving science is the detection of large samples of galaxy clusters up to redshifts z > 1 in order to study the large-scale structure in the universe and test cosmological models including dark energy. In addition, eROSITA is expected to yield a sample of a few million active galactic nuclei, including obscured objects, revolutionizing our view of the evolution of supermassive black holes. The survey will also provide new insights into a wide range of astrophysical phenomena, including X-ray binaries, active stars, and diffuse emission within the galaxy. The eROSITA flight model has passed calibration and integration and is currently (September 2016) in end-to-end testing just prior to its shipment to Russia.
      PubDate: 2017-03-16T01:27:42.215439-05:
      DOI: 10.1002/asna.201713324
  • Synergy with new radio facilities: From LOFAR to SKA
    • Authors: R. Morganti
      Abstract: Radio astronomy is going through major changes and new radio telescopes are coming online, paving the way to the Square Kilometre Array (SKA). Their new capabilities—e.g., large field of view combined with good spatial resolution, broad instantaneous band, and fast response to transient objects—offer unique possibilities for the science. I will give a brief overview of these facilities, focusing mostly on LOFAR (LOw Frequency Array) and on the topics where a strong synergy with XMM (and X-ray in general) is present. I will describe the imaging surveys that are ongoing and the possibilities for the studies of active galactic nuclei (AGN) and galaxy clusters. New exciting capabilities are also becoming available for the study of the transient radio sky. Thanks to the rapid response of the new radio telescopes, radio frequencies will provide alerts on new transients and trigger other facilities. All these capabilities (and more) will be incorporated in the SKA. The entire project is evolving and progressing rapidly, and I will give a brief update of its present status.
      PubDate: 2017-03-16T01:27:29.820594-05:
      DOI: 10.1002/asna.201713325
  • On a correlation among azimuthal velocities and the flyby anomaly sign
    • Authors: L. Acedo; Ll. Bel
      Abstract: BackgroundData of six flybys, those of Galileo I, Galileo II, NEAR, Cassini, Rosetta, and Messenger were reported by Anderson et al. (2008). Four of them: Galileo I, NEAR, Rosetta, and Messenger gain Newtonian energy during the flyby transfer, while Galileo II and Cassini lose energy. In both cases this is a surprising anomaly since Newtonian forces originate from a potential and they are, therefore, conservative.Materials and MethodsWe use a Whiteheadian theory of gravity to analyze the anomalies.ResultsHere we show that the gravitational field of a rotating planet, as derived from this new model, introduces a nonconservative force that gives a partial, but in our opinion satisfactory, explanation of these anomalies.ConclusionThis model also suggests a correlation between the sign of the anomaly and the sign of the azimuthal velocity at perigee.
      PubDate: 2017-03-15T20:00:56.875389-05:
      DOI: 10.1002/asna.201613151
  • Follow-up of eROSITA and Euclid Galaxy Clusters with XMM-Newton
    • Authors: T. H. Reiprich
      Abstract: A revolution in galaxy cluster science is only a few years away. The survey machines eROSITA and Euclid will provide cluster samples of statistical quality never seen before. XMM-Newton will be the key instrument to exploit these rich datasets in terms of detailed follow-up of the cluster hot gas content, systematically characterizing subsamples as well as exotic new objects.
      PubDate: 2017-03-13T03:00:32.913464-05:
      DOI: 10.1002/asna.201713354
  • Follow-up of isolated neutron star candidates from the eROSITA survey
    • Authors: A. M. Pires; A. D. Schwope, C. Motch
      Abstract: Peculiar groups of X-ray emitting isolated neutron stars, which include magnetars, the “magnificent seven”, and central compact objects in supernova remnants, escape detection in standard pulsar surveys. Yet, they constitute a key element in understanding the neutron star evolution and phenomenology. Their use in population studies in the galactic scale has been hindered by the rarity of their detection. The all-sky survey of the extended Roentgen Survey with an Imaging Telescope Array (eROSITA) on-board the forthcoming Spectrum-Roentgen-Gamma (SRG) mission has the unique potential to unveil the X-ray faint part of the population and constrain evolutionary models. To create a forecast for the 4-year all-sky survey, we perform Monte Carlo simulations of a population synthesis model, where we follow the evolutionary tracks of thermally emitting neutron stars in the Milky Way and test their detectability. In this paper, we discuss strategies for pinpointing the most promising candidates for follow-up observing campaigns using current and future facilities.
      PubDate: 2017-03-08T03:01:15.848246-05:
      DOI: 10.1002/asna.201713333
  • A multi-observatory database of X-ray pulsars in the Magellanic Clouds
    • Authors: J. Yang; S. G. T. Laycock, J. J. Drake, M. J. Coe, S. Fingerman, J. Hong, V. Antoniou, A. Zezas
      Abstract: Using hundreds of XMM-Newton and Chandra archival observations and nearly a thousand RXTE observations, we have generated a comprehensive library of the known pulsars in the Small and Large Magellanic Clouds (SMC and LMC). The pulsars are detected multiple times across the full parameter spaces of X-ray luminosity (LX = 1031 − 38 erg s− 1) and spin period (P  1,000 s), and the library enables time-domain studies at a range of energy scales. The high time resolution and sensitivity of the European Photon Imaging cameras are complemented by the angular resolution of Chandra and the regular monitoring of RXTE. Our processing pipeline uses the latest calibration files and software to generate a suite of useful products for each pulsar detection: event lists, high-time-resolution light curves, periodograms, spectra, and complete histories of P˙, the pulsed fraction, and so on, in the broad (0.2–12 keV), soft (0.2–2 keV), and hard (2–12 keV) energy bands. After combining the observations from these telescopes, we found that 27 pulsars show long-term spin up and 24 long-term spin down. We also used the faintest and brightest sources to map out the lower and upper boundaries of accretion-powered X-ray emission: the propeller line and the Eddington line, respectively. We are in the process of comparing the observed pulse profiles to geometric models of X-ray emission in order to constrain the physical parameters of the pulsars. Finally, we are preparing a public release of the library so that it can be used by others in the astronomical community.
      PubDate: 2017-03-08T03:00:53.095195-05:
      DOI: 10.1002/asna.201713334
  • Future perspectives for abundance measurements in clusters of galaxies
           with XMM-Newton
    • Authors: J. Plaa; F. Mernier
      Abstract: The CHEERS (CHEmical enrichment reflection grating spectrometer sample) observations of clusters of galaxies with XMM-Newton have shown to be valuable to constrain the chemical evolution of the universe. The soft X-ray spectrum contains lines of the most abundant metals from N to Ni, which provide relatively accurate abundances that can be compared to supernova enrichment models. The accuracy of the abundances is currently limited by systematic uncertainties introduced by the available instruments and uncertainties in the modeling of the spectra, which are of the order of 20–30%. We discuss the possible gain of extending the current samples at low and high redshift. We conclude that expanding the samples would be expensive in terms of exposure time, but will not yield significantly improved results, because the current samples already reach the systematic limits. New instrumentation, like Astro-H2 and ATHENA, as well as improvements to the atomic databases, are needed to make significant advances in this field.
      PubDate: 2017-03-08T03:00:26.946993-05:
      DOI: 10.1002/asna.201713346
  • Stellar X-ray accretion signatures
    • Authors: P. C. Schneider; H. M. Günther, J. Robrade
      Abstract: Accretion is observed in a wide range of objects with partially overlapping properties. In this paper, we focus on accretion in young stars. Material impacting the stellar surface is shock-heated to temperatures of a few 106 K (MK), which is ideally suited for observations in the X-ray regime. Indeed, young, accreting stars show a surplus of cool plasma, thought to be somehow related to accretion, the so-called soft excess. High-resolution grating spectroscopy with instruments like the Reflection Grating Spectrometer (RGS) on board XMM-Newton allows us to infer the properties of this cool plasma. We present results from our recent 250-ks XMM-Newton/Chandra program targeting the prototypical T Tau system and compare them with other accreting systems, focusing on potentially different accretion modes. We find a strong cool excess in T Tau but line ratios indicative of low densities. Thus, the cool excess in T Tau, and likely in other accreting stars, is not caused directly by postshock emission from accretion spots, which are expected in magnetic stars like T Tau. Rather, the coolest plasma might be linked to other processes in accreting stars, such as an interaction of the corona with postshock plasma.
      PubDate: 2017-03-08T02:55:30.267126-05:
      DOI: 10.1002/asna.201713331
  • Tidal disruption of stars by super-massive black holes—XMM-Newton
           highlights and the next decade
    • Authors: S. Komossa
      Abstract: This article provides a summary of XMM-Newton highlights on stellar tidal disruption events. First found with ROSAT, ongoing and upcoming sky surveys will detect these events in the thousands. In X-rays, tidal disruption events (TDEs) provide us with powerful new probes of accretion physics under extreme conditions and on short timescales and of relativistic effects near the super-massive black holes (SMBHs), of the formation and evolution of disk winds near or above the Eddington limit, and of the processes of high-energy emission from newly launched radio jets. TDEs serve as signposts of the presence of dormant single black holes at the cores of galaxies, and of binary black holes as well, since TDE lightcurves are characteristically different in the latter case. XMM-Newton has started to contribute to all of these topics, and a rich discovery space is opening up in the next decade.
      PubDate: 2017-03-06T00:55:25.669192-05:
      DOI: 10.1002/asna.201713339
  • High-resolution X-ray spectroscopy: The coming-of-age
    • Authors: J. S. Kaastra
      Abstract: Since the launch of Chandra and XMM-Newton, high-resolution X-ray spectra of cosmic sources of all kinds have become available. These spectra have resulted in major scientific breakthroughs. However, because of the techniques used, in general, high-quality spectra can be obtained only for the brightest few sources of each class. Moreover, except for the most compact extended sources, such as cool core clusters, grating spectra are limited to point sources. Hitomi made another major step forward, providing for the first time a high-quality spectrum of an extended source and improved spectral sensitivity in the Fe-K band. For point sources with the proposed Arcus mission, and for all sources with the launch of Athena, X-ray spectroscopy will become mature. It will allow us to extend the investigations from the few handful of brightest sources of each category to a large number of sources far away in space and time, or to get high time resolution and high spectral resolution spectra of bright time-variable sources.
      PubDate: 2017-03-06T00:50:54.2685-05:00
      DOI: 10.1002/asna.201713322
  • Cosmic X-ray surveys of active galactic nuclei: The synergy between X-ray
           and infrared observations
    • Authors: D. M. Alexander
      Abstract: We briefly review the synergy between X-ray and infrared observations for active galactic nuclei (AGNs) detected in cosmic X-ray surveys, primarily with XMM-Newton, Chandra, and NuSTAR. We focus on two complementary aspects of this X-ray–infrared synergy: (a) the identification of the most heavily obscured AGNs, and (b) the connection between star formation and AGN activity. We also briefly discuss future prospects for X-ray–infrared studies over the next decade.
      PubDate: 2017-03-06T00:50:37.706124-05:
      DOI: 10.1002/asna.201713326
  • Climatological and ultraviolet-based habitability of possible exomoons in
           F-star systems
    • Authors: S. Sato; Zh. Wang, M. Cuntz
      Abstract: BackgroundThe identification of conditions suitable for life is considered a key element of modern-day astronomy, astrophysics, and astrobiology. This research encompasses the environments of stars of different spectral types and evolutionary status. In this article, we focus on the possibility of habitable moons in selected F-star systems.Materials and MethodsWe explore the astrobiological significance of F-type stars of spectral type between F5 V and F9.5 V, which possess Jupiter-type planets within or close to their climatological habitable zones. These planets, or at least a subset of those, may also possess rocky exomoons, which potentially offer habitable environments. Our work considers eight selected systems. The Jupiter-type planets in these systems are in notably differing orbits with eccentricities between 0.08 (about Mars) and 0.72. We consider the stellar UV environments provided by the photospheric stellar radiation, which allows us to compute the UV habitable zones for the systems. Following previous studies, deoxyribonucleic acid (DNA) is taken as a proxy for carbon-based macromolecules following the paradigm that extraterrestrial biology might be based on hydrocarbons.ResultsWe found that the damage inflicted on DNA is notably different for the range of systems studied, and also varies according to the orbit of the Jupiter-type planet, especially for systems of high ellipticity, as expected. Furthermore, the UV levels in the CLI-HZs of the F-type stars are generally more severe than for the solar environment, except for regions beyond the outer limits of the general habitable zones. Particular emphasis was placed on locations akin to Earth-equivalent (i.e., homeothermic) positions in the Solar System. The general conditions of habitability in F-star systems are also affected by the rapidness of stellar evolution; nonetheless, based on previous research on the origin of life on Earth, a generally favorable assessment about the overall possibility of life around F-type stars can be conveyed. For some systems studied here, excessive values of damage are attained if compared to today's Earth or during the Archean eon.ConclusionConsidering that the detection of exomoons around different types of stars will remain challenging in the foreseeable future, we view our work also as an example and template for investigating the combined requirements of climatological and UV-based habitability for exosolar objects. Further studies for systems of stars with other spectral types and/or other evolutionary status will be considered as part of our future research.
      PubDate: 2017-03-06T00:45:36.497952-05:
      DOI: 10.1002/asna.201613279
  • Editor's note
    • Authors: N. Schartel
      PubDate: 2017-03-06T00:45:25.657234-05:
      DOI: 10.1002/asna.201713320
  • An Arabic report about supernova SN 1006 by Ibn Sīnā (Avicenna)
    • Authors: R. Neuhäuser; C. Ehrig-Eggert, P. Kunitzsch
      Abstract: We present here an Arabic report about supernova 1006 (SN 1006) written by the famous Persian scholar Ibn Sīnā (Lat. Avicenna, AD 980–1037), which has not been discussed in astronomical literature before. The short observational report about a new star is part of Ibn Sīnā's book called al-Shifā', a work on philosophy including physics, astronomy, and meteorology. We present the Arabic text and our English translation. After a detailed discussion of the dating of the observation, we show that the text specifies that the transient celestial object was stationary and/or tail-less (a star among the stars), that it remained for close to 3 months getting fainter and fainter until it disappeared, that it threw out sparks, that is, it was scintillating and very bright, and that the colour changed with time. The information content is consistent with the other Arabic and non-Arabic reports about SN 1006. Hence, it is quite clear that Ibn Sīnā refers to SN 1006 in his report, given as an example for transient celestial objects in a discussion of Aristotle's Meteorology. Given the wording and the description, for example, for the colour evolution, this report is independent of other reports known so far.
      PubDate: 2017-02-27T03:25:25.478264-05:
      DOI: 10.1002/asna.201613200
  • Elemental abundance analyses with DAO spectrograms: XL
    • Authors: S. J. Adelman; A. F. Gulliver, L. J. Gucella
      Abstract: We continue our series of high-quality fine analyses of slowly and moderately rotating normal and peculiar Main Sequence Band B, A, and F stars. We use Kurucz's ATLAS9 model atmospheres in Local Thermodynamic Equilibrium and WIDTH9 codes and high signal-to-noise (>200) spectrograms currently obtained with a charge-coupled device detectors on the long camera of the Coudé spectrograph of the 1.22-m telescope of the Dominion Astrophysical Observatory. We were surprised that the elemental abundances of the A2 V star HR 196 indicated that it was slightly metal-poor relative to the Sun. Its projected rotational velocity is 36±2 km s−1. Its abundances are for the most part close to those of α Dra (A0 III), a star with less than solar abundances. We found that the B8 V star HR 6968 (vsini=36±2 km s−1) was a peculiar member of the HgMn class with elemental abundances somewhat similar to those of 53 Tau. Most significantly, it has an overabundance of Mn, and Hg II λ3984 is absent. Our analysis of the sharp-lined (vsini=7.0±0.5 km s−1) HgMn star HR 7664 is an improvement of the earlier co-added photographic study of this series, with reduced scatter about the mean abundance for each atomic species. Further, we found abundances for several additional atomic species including Xe II.
      PubDate: 2017-02-27T03:20:29.810721-05:
      DOI: 10.1002/asna.201613214
  • Speckle observations with PISCO in Merate (Italy): XV
    • Authors: J.-L. Prieur; M. Scardia, L. Pansecchi, R. W. Argyle, A. Zanutta, E. Aristidi
      Abstract: We present relative astrometric measurements of visual binaries, made in 2014 with the speckle camera Pupil Interferometry Speckle camera and COronagraph (PISCO) at the 102-cm Zeiss telescope of Brera Astronomical Observatory, in Merate. Our observing list contains orbital couples as well as binaries whose motion is still uncertain. We obtained 224 new measurements of 218 visual binary stars, with angular separations in the range 0′′.15–10′′, and an average accuracy of 0′′.015. The mean error on the position angles is 0°.5. Most of the position angles were determined without the usual 180° ambiguity with the application of triple-correlation techniques and/or by inspection of the long integration files. We complete this data with the results of a study of the multiple system ADS 6993 with PISCO during the period 2004–2014 and propose a new method to resolve part of the 180-degree ambiguity with the autocorrelations only. We then present new revised orbits for ADS 671, 1615, 1709, 5447, 10075, and 12447, partly derived from PISCO observations. The corresponding estimated values for the masses of those systems are compatible with the spectral types.
      PubDate: 2017-02-27T03:15:35.435544-05:
      DOI: 10.1002/asna.201613244
  • Possible origin of Theia, the Moon-forming impactor with Earth
    • Authors: R. Dvorak; B. Loibnegger, T. I. Maindl
      Abstract: BackgroundThe problem of the formation of the Moon is still not explained satisfactorily. While it is a generally accepted scenario that the last giant impact on Earth between some 50 to 100 million years after the starting of the formation of the terrestrial planets formed our natural satellite, there are still many open questions like the isotopic composition, which is identical for these two bodies. In our investigation, we will not deal with these problems of chemical composition but rather undertake a purely dynamical study to find out the probability of a Mars-sized body (Theia) to collide with the Earth after the formation of the Earth-like planets.Materials and MethodsWe assume an additional massive body between Venus and Earth, respectively Earth and Mars, which formed there at the same time as the other terrestrial planets. We have undertaken massive n-body integrations of such a planetary system with four inner planets (we excluded Mercury but assumed one additional body as mentioned before) and the gas giants Jupiter and Saturn. For the present positions of the planets, we have undertaken the integrations for 100 Myrs to be able to check for stable orbits of Theia for or up to tens of millions of years.ResultsWe find a probable origin of the Earth impactor at a semi-major axis of 1:16 AU < aTheia < 1:195 AU; a Theia inside the orbit of Earth suffers from collisions on much shorter time scales.ConclusionWe can provide a statistical estimation of the collision velocities as well as the collision angles, which will then serve as the basis for further investigation with detailed smooth(ed) particle hydrodynamics computations.
      PubDate: 2017-02-22T21:15:32.081837-05:
      DOI: 10.1002/asna.201613209
  • Suggestion for the search for TiH2 molecule in an interstellar molecular
    • Authors: M. K. Sharma; P. G. Musrif, M. Sharma, S. Chandra
      Abstract: Two molecules TiH and TiO, bearing titanium, were discovered in the year 1979 in the atmosphere of cool M-type stars. Now, TiO2 has been discovered in the environment of the red supergiant VY CMa. A natural question therefore arises for the search of TiH2 in an interstellar molecular cloud. Detection of TiH2is quite probable as the cosmic abundance of hydrogen is about 1,900 times that of oxygen. Using GAUSSIAN 2009, we have calculated the rotational and centrifugal distortion constants, and electric dipole moment of TiH2, where B3LYP method and cc-pVtz basis are used. Using these physical parameters, we have calculated the energies of rotational levels, and the intensities and Einstein A-coefficients for the transitions between the levels. We have found a large number of lines which may help in the identification of titanium dihydride (TiH2) in an interstellar molecular cloud.
      PubDate: 2017-02-20T01:30:37.983023-05:
      DOI: 10.1002/asna.201613142
  • Comparison of XPM and UCAC4 catalogues in the galactic coordinate system
    • Authors: V. V. Vityazev; A. S. Tsvetkov, S. D. Petrov, D. A. Trofimov
      Abstract: This paper presents the results of the comparison of the galactic reference frames realized by the catalogues XPM and UCAC4. Based on about 40 million stars common to both catalogues, the systematic differences of the galactic coordinates and proper motions have been derived for 12 magnitudes in 0.5m width bins with the mean J-values from 10m.25 to 15m.75. The systematic differences were represented by vector spherical harmonics, with the magnitude equation taken into consideration. The mutual orientation of the frames was found to be at the level of 10 mas. It is concluded that these differences are negligible in comparison with the accuracy of the implementation of the standard galactic coordinate system MAS 1958. We investigated two features of the XPM catalogue. First, unlike the HCRF and UCAC4 catalogues, whose proper motions are tied to the quasars and galaxies, the XPM catalogue implements a reference system based only on galaxies. Second, the XPM catalogue has two systems of proper motions—XPMx and XPMp, referred to the two galaxy sub-catalogues of the project 2MASS—PSC and XSC. The study of the differences XPMx−XPMp showed that they are free of the magnitude equation. The speed of relative rotation of XPMx over XPMp was found to be ω=0.453±0.003 mas/year, which exceeds the residual rotation of the HCRF (0.25 mas/year). Analysis of systematic differences XPMx−UCAC4 and XPMp−UCAC4 showed that both frames XPMx and XPMp have an appreciable rotation speed relative to the UCAC4 (hence the ICRF), especially large (up to 2 mas/year) for the brightest stars in our range. This shows that a relatively high speed of rotation of the two frames XPMx and XPMp with respect to the UCAC4 is a consequence of the transition from a combined “quasar-galaxy” to a purely “galactic” reference system. It is shown that the systematic difference between the proper motions of stars can be interpreted within the Ogorodnikov–Milne kinematic model of the velocity field.
      PubDate: 2017-02-17T02:55:55.024416-05:
      DOI: 10.1002/asna.201613220
  • Affordable echelle spectroscopy of the eccentric HAT-P-2, WASP-14, and
           XO-3 planetary systems with a sub-meter-class telescope
    • Authors: Z. Garai; T. Pribulla, Ľ. Hambálek, E. Kundra, M. Vaňko, S. Raetz, M. Seeliger, C. Marka, H. Gilbert
      Abstract: BackgroundA new off-the-shelf, low-cost echelle spectrograph was installed recently on the 0.6-m telescope at the Stará Lesná Observatory (Slovakia). In this paper, we describe in detail the radial velocity (RV) analysis of the first three transiting planetary systems, namely HAT-P-2, WASP-14, and XO-3, observed with this instrument.Materials and MethodsFirst, we reduced and analyzed our RV observations. Subsequently, we compared our data with previously published RV data. We were curious about the precision of our measurements in comparison to that of the RV data achieved with echelle spectrographs of other sub-meter-, meter- and 2-m-class telescopes. Another question was the applicability of our RV data for modeling orbital parameters. For this purpose, the previously published data were analyzed in the same way as our RV data in order to determine and compare the parameters. Finally, we combined and analyzed all used RV data per object.ResultsThe accuracy of our data is well comparable with the average RV scatter achieved with other sub-meter and meter-class telescopes. In comparison with 2-m-class telescopes, our instrumentation gives an RV scatter of about one order greater. On the other hand, our fit results show that RV data obtained with our instrumentation can be used to determine orbital parameters of these objects.ConclusionBased on our results, we can conclude that the spectrograph is a useful instrument for the study of objects with a relatively small RV amplitude. Resulting values are sufficient for exoplanet RV detections and spectroscopic follow-up measurements of massive exoplanets on close-in orbits.
      PubDate: 2017-02-17T02:55:33.890992-05:
      DOI: 10.1002/asna.201613208
  • Thermomagnetic instability in hot spherical plasma shells
    • Authors: M. Mond; R. Arlt, E. Liverts
      Abstract: A linear stability analysis of ionized spherical plasma shells with radial temperature gradients and an external poloidal magnetic field is presented. It is shown that both hydromagnetic and thermomagnetic effects can lead to an amplification of waves. Solutions are obtained for a wide range of plasma beta values and the thermomagnetic transport coefficient. The conditions under which the instability grows are found and the characteristic growth rates are calculated. The regime at which the thermomagnetic instability is effective is considered. Applications for the solar corona are discussed.
      PubDate: 2017-02-16T03:00:49.072384-05:
      DOI: 10.1002/asna.201613221
  • Sizes of solar active regions at 8 mm
    • Authors: J. Kallunki; M. Uunila
      Abstract: BackgroundWe investigate the sizes of 86 non-flaring solar active regions with respect to the brightness temperature at 8 mm and active region magnetic field strength.Materials and MethodsThe data were collected in AprilŰSeptember, 2014, and AprilŰJuly, 2015 at Aalto University, Metsähovi Radio Observatory with the 14-m radio telescope. The observations were made at the maximum of the solar cycle 24. We used active region magnetic field strength values measured with the Helioseismic and Magnetic Imager instrument aboard the Solar Dynamics Observatory.ResultsWe calculated that the mean active region size in percentage of the full solar disk is 3.7 ś 0.86%. In addition, the mean temperature of selected active regions is around 109% of the quiet Sun level and the average magnetic field strength of the studied active region is 1,400 G.ConclusionsOur results show correlation between active region sizes, the total brightness temperature of the Sun, and the active region magnetic field strengths.
      PubDate: 2017-02-16T03:00:38.524927-05:
      DOI: 10.1002/asna.201613196
  • Interpretation of the historic Yemeni reports of supernova SN 1006: Early
           discovery in mid-April 1006?
    • Authors: R. Neuhäuser; D. L. Neuhäuser, W. Rada, J. Chapman, D. Luge, P. Kunitzsch
      Abstract: The recently published Yemeni observation report about SN 1006 from al-Yamānī clearly gives AD 1006 April 17 ± 2 (mid-Rajab 396h) as the first observation date. Since this is ∼1.5 weeks earlier than the otherwise earliest reports (April 28 or 30) as discussed so far, we were motivated to investigate an early sighting in more depth. We searched for additional evidences from other areas like East Asia and Europe. We found that the date given by al-Yamānī is fully consistent with other evidence, including the following: (a) SN 1006 rose several times half an hour after sunset (al-Yamānī), which is correct for the location of Ṣancā' in Yemen for the time around April 17, but it would not be correct for late April or early May. (b) The date (third year, third lunar month, 28th day wuzi, Ichidai Yoki) for an observation of a guest star in Japan is inconsistent (there is no day wuzi in that lunar month), but may be dated to April 16 by reading a wuwu date rather than a wuzi date. (c) There is observational evidence that SN 1006 was observed in East Asia in early or mid-April; for the second half of April, a bad weather (early monsoon) period is not unlikely— there is a lack of night reports. (d) The observer in St. Gallen reported to have seen SN 1006 for 3 months, which must have ended at the very latest on AD 1006 July 10, given his northern location, so that his observations probably started in April. We conclude that the correctly reported details give quite high confidence in the fully self-consistent report of al-Yamānī, so that the early discovery date should be considered seriously.
      PubDate: 2017-02-16T02:55:27.55296-05:0
      DOI: 10.1002/asna.201613139
  • Time-series analysis of long-term photometry of BM Canum Venaticorum
    • Authors: L. Siltala; L. Jetsu, T. Hackman, G. W. Henry, L. Immonen, P. Kajatkari, J. Lankinen, J. Lehtinen, S. Monira, S. Nikbakhsh, A. Viitanen, J. Viuho, T. Willamo
      Abstract: Long-term photometry is commonly used to monitor chromospheric activity of late–type stars. We study standard Johnson differential V photometry of the RS CVn binary BM Canum Venaticorum (BM CVn) spanning over a quarter of a century. Our main aims are to determine the activity cycles, the rate of surface differential rotation, and the rotation period of the active longitudes of BM CVn. The continuous period search (CPS) algorithm is applied to the photometry. The changes of the mean and amplitude of the light curves are used to search for activity cycles. The rotation period changes give an estimate of the rate of surface differential rotation. The Kuiper method is applied to the epochs of the primary and secondary minima to search for active longitudes. The photometry reveals the presence of a stable mean light curve (MLC) connected to the orbital period Porb=20.d6252 of this binary. We remove this MLC from the original V magnitudes, which gives us the corrected V′magnitudes. These two samples of Vand V′data are analyzed separately with CPS. The fraction of unreliable CPS models decreases when the MLC is removed. The same significant activity cycle of approximately 12.5 years is detected in both V and V′samples. The estimate for the surface differential rotation coefficient, k⩾0.10, is the same for both samples, but the number of unrealistic period estimates decreases after removing the MLC. The same active longitude period of Pal=20.d511 ± 0.d005 is detected in the V and V′ magnitudes. This long-term regularity in the epochs of primary and secondary minima of the light curves is not caused by the MLC. On the contrary, the MLC hampers the detection of active longitudes.
      PubDate: 2017-02-16T02:50:35.131205-05:
      DOI: 10.1002/asna.201613205
  • The Großschwabhausen binary survey
    • Authors: M. Mugrauer ; S. Buder, F. Reum, A. Birth
      Abstract: BackgroundSince 2009, the Großschwabhausen binary survey is being carried out at the University Observatory Jena. This new imaging survey uses available time slots during photometric monitoring campaigns, caused by nonphotometric weather conditions, which often exhibit good atmospheric seeing. The goal of the project is to obtain current relative astrometric measurements of the binary systems that are listed in the Washington Visual Double Star Catalog.Materials and MethodsFor the survey we use the Refraktor-Teleskop-Kamera at the University Observatory Jena to take imaging data of selected visual binary systems.ResultsIn this paper, we characterize the target sample of the survey, describe the imaging observations and the astrometric measurements including the astrometric calibration, and present the relative astrometric measures of 352 binaries that could be obtained during the course of the Großschwabhausen binary survey, so far.
      PubDate: 2017-02-15T03:05:33.07143-05:0
      DOI: 10.1002/asna.201613204
  • Diffraction of solar neutrinos at the Earth's solid core
    • Authors: R. Lauter
      Abstract: BackgroundThis paper presents a gedankenexperiment or “thought experiment” on the solar neutrino beam in regard to a diffraction study of the Earth's core.Materials and MethodsThe Sun is the source of the most intense neutrino radiation on Earth. Owing to the Sun's long distance from the Earth it forms a parallel beam of white radiation as well as discrete lines. The coherent scattering of these neutrinos at the Earth's solid core produces a diffraction pattern on the Earth's night side.ResultsI will show that this diffraction pattern will be most likely observable on the Earth's surface by using a detector configuration that is located between the tropics. There has not been any neutrino detector that is located on the Earth's surface and suitable for these measurements.ConclusionAn investigation of the diffraction pattern of the solar neutrino beam would provide a tool for studying not only the Earth's center but also the neutrinos themselves.
      PubDate: 2017-02-15T03:05:25.114465-05:
      DOI: 10.1002/asna.201613049
  • Another look at the size of the low-surface-brightness galaxy VCC 1661 in
           the Virgo Cluster
    • Authors: A. Koch; C. S. Black, R. M. Rich, F. A. Longstaff, M. L. M. Collins, J. Janz
      Abstract: The morphologies of individual cluster galaxies are an important path to studying galaxy formation and evolution. Here, we present new wide-field images of the low-surface-brightness Virgo Cluster dwarf galaxy VCC 1661. The extant literature lists a broad range of radii for this object, covering a factor of more than four, depending on the filters used and the details of the analyses. While some studies find a radius typical of other Virgo dwarfs and note the normality of this object, any larger spatial extent, taken at face value, would render this galaxy the largest dwarf in the Virgo Cluster samples. Confirmation of a large extent of dwarf galaxies has often led to the discovery of tidal tails and would then, also in VCC 1661, indicate a severe state of tidal disruption. Given the importance of galactic sizes for assessing tidal interactions of the satellites with their hosts, we thus combine our surface brightness profile with data from the literature to investigate further the nature of this galaxy. However, our new characteristic radius for VCC 1661 of re = 24.1″ ± 7.7″ and the previously noted smooth appearance of its isophotes are fully consistent with the remainder of the Advanced Camera for Surveys Virgo Cluster Survey dwarf galaxy population without any need to invoke tidal perturbations.
      PubDate: 2017-02-15T03:00:43.355218-05:
      DOI: 10.1002/asna.201613274
  • New aspects of photon propagation in expanding universes
    • Authors: H.-J. Fahr; M. Heyl
      Abstract: BackgroundModern cosmology assumes that the cosmic microwave background (CMB) radiation is a relict of the much hotter electromagnetic radiation field from the early recombination era of the universe. Its present very low radiation temperature TCMB = 2.735 K thereby is explained by the fact that the cosmic photons in the expanding universe undergo a wavelength stretching according to λ/λ0 = S/S0, where S denotes the scale of the universe. The present-day CMB temperature hence simply expresses the factor by which the universe has grown since the recombination era.Materials and MethodsOn the basis of well-known facts of Special and General Relativity (SRT and GRT), we reinvestigate the behavior of freely propagating cosmic photons in dynamic Robertson-Walker spacetime geometries and show that in the system of the propagating photon, due to the fact that no time lapses in this proper system, the photon does not change its initial state, that is, its wavelength and energy. We do, however, also show that the global beat of the time changes with the cosmic world time or the cosmic scale S. That means cosmic photons do not change their state, till they are registered by a local detector, that is, a local clock.ResultsWe claim that the energy density of cosmic photons which enters the energy-momentum tensor of Einstein's GRT field equations does not scale like S−4 as assumed in present-day cosmology, but like S−3, that is, identically to the behavior of the energy densities of baryonic or dark matter, meaning that the energy density of photons in the present-day universe cannot be neglected, but counts substantially for the expansion history of the universe. Nevertheless, we show that cosmic photons measured with a present-day detector (local clock) locally will show their cosmological redshift, explaining the present-day CMB Planck spectrum with a Planck temperature of 2.735 K.ConclusionsAs the energy density of cosmic photons cannot be neglected, their contribution in the GRT energy-momentum tensor is important over all phases of the expansion of the universe. They are thus acting identical to the way how dark matter acts and influences cosmic expansion. This means that the present-day claim for a dark matter contribution in cosmic expansion by Ωdark≃0.23 can be substantially relaxed.
      PubDate: 2017-02-15T03:00:29.291116-05:
      DOI: 10.1002/asna.201613216
  • Hamburger Sternwarte plate archives: Historic long-term variability study
           of active galaxies based on digitized photographic plates
    • Authors: M. Wertz; D. Horns, D. Groote, T. Tuvikene, S. Czesla, J. H. M. M. Schmitt
      Abstract: BackgroundAt the Hamburger Sternwarte, an effort was started in 2010 with the aim of digitizing its more than 45,000 photographic plates and films stored in its plate archives. At the time of writing, more than 31,000 plates have already been made available on the Internet for researchers, historians, and the interested public.Materials and MethodsThe digitization process and the Internet presentation of the plates and accompanying handwritten material (plate envelopes, logbooks, observer notes) are presented here. To fully exploit the unique photometric and astrometric data, stored on the plates, further processing steps are required including registering the plate to celestial coordinates, masking of the plates, and a calibration of the photoemulsion darkening curve. To demonstrate the correct functioning of these procedures, historical light curves of two bright BL Lac-type active galactic nuclei are extracted.ResultsThe resulting light curve of the blazar 1ES 1215+303 exhibits a large decrease in the magnitude from 14.25−0.12+0.07 to 15.94−0.13+0.09 in about 300 days, which proves the variability in the optical region. Furthermore, we compare the measured magnitudes for the quasar 3C 273 with contemporaneous measurements and find good agreement.
      PubDate: 2017-02-15T02:55:31.635097-05:
      DOI: 10.1002/asna.201613201
  • V-type near-Earth asteroids: Dynamics, close encounters and impacts with
           terrestrial planets
    • Authors: M. A. Galiazzo; E. A. Silber, D. Bancelin
      Abstract: BackgroundAsteroids colliding with planets vary in composition and taxonomical type. Among Near-Earth Asteroids (NEAs) are the V-types, basaltic asteroids that are classified via spectroscopic observations.Materials and Methodswe performed numerical simulations and statistical analysis of close encounters and impacts between V-type NEAs and the terrestrial planets over the next 10 Myr. We study the probability of V- type NEAs colliding with Earth, Mars and Venus, as well as the Moon. We perform a correlational analysis of possible craters produced by V-type NEAs, using available catalogs for terrestrial impact craters.ResultsThe results suggest that V-type NEAs can have many close encounters below 1 LD and even some of them impacts with all the terrestrial planets, the Earth in particular. There are four candidate craters on Earth that were likely caused by V-type NEAs.ConclusionAt least 70% of the V-type NEAs can have close encounters with the terrestrial planets (and 58% with the Moon) . They can collide with all the terrestrial planets. In particular for the Earth the average rate is one every ∼12 Myr. The two craters with the highest probability of being generated by an impact with a basaltic impactor are: the Strangways crater (24 km diameter) in Australia and the Nicholson crater (12.5 km diameter) in Canada.
      PubDate: 2017-02-10T00:15:43.761223-05:
      DOI: 10.1002/asna.201613273
  • KIC011764567: An evolved Kepler-star showing substantial flare activity
    • Authors: M. Kitze; A. A. Akopian, V. Hambaryan, G. Torres, R. Neuhäuser
      Abstract: We intensively studied the flare activity on the stellar object KIC011764567. The star was thought to be a solar type, with a temperature of Teff≈(5640±200) K, log(g) = (4.3 ± 0.3) dex, and a rotational period of Prot≈22 days. High-resolution spectra turn the target to an evolved object with Teff=(5300±150) K, a metalicity of [m/H] =(−0.5±0.2), a surface gravity of log(g) = (3.3 ± 0.4) dex, and a projected rotational velocity of v sin i = (22 ± 1) km s−1. Within an observing time span of 4 years, we detected 150 flares in Kepler data in the energy range 1036–1037 erg. From a dynamical Lomb–Scargle periodogram, we have evidence for differential rotation as well as for stellar spot evolution and migration. On analyzing the occurrence times of the flares, we found hints for a periodic flare frequency cycle of 430–460 days, a significant increase with an increase in threshold of the flares' equivalent duration. One explanation is a very short activity cycle of the star with that period. Another possibility, also proposed by others in similar cases, is that the larger flares may be triggered by external phenomena, such as magnetic interaction with an unseen companion. Our high-resolution spectra show that KIC011764567 is not a short-period binary star.
      PubDate: 2017-02-10T00:10:35.785995-05:
      DOI: 10.1002/asna.201613053
  • Issue Information: Astron. Nachr. 10/2016
    • PubDate: 2016-12-16T04:58:31.443331-05:
      DOI: 10.1002/asna.201690022
  • Cover Picture: Astron. Nachr. 10/2016
    • Abstract: Multiwavelength TRACE observation of the Bastille day flare occurred on 2000 July 14 (see F. Zuccarello, this issue, p. 1070). (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2016-12-16T04:58:31.11246-05:0
      DOI: 10.1002/asna.201690021
  • Issue Information: Astron. Nachr. 10/2016
    • PubDate: 2016-11-29T03:06:41.556964-05:
      DOI: 10.1002/asna.201690019
  • Cover Picture: Astron. Nachr. 10/2016
    • Abstract: Multiwavelength TRACE observation of the Bastille day flare occurred on 2000 July 14 (see F. Zuccarello, this issue, p. 1070). (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2016-11-29T03:06:41.187428-05:
      DOI: 10.1002/asna.201690018
  • Issue Information
    • Pages: 1 - 2
      Abstract: No abstract is available for this article.
      PubDate: 2016-11-24T00:26:06.130691-05:
      DOI: 10.1111/apel.12116
  • Four-G Episode and the elevated risks
    • Authors: Iwan J Azis
      Pages: 3 - 32
      Abstract: Complacency and a false perception that markets will correct imbalances during two decades of ‘Great Moderation’ led to ‘Global Imbalances’. The low interest rates and a lack of proper oversight, combined with a perception that housing prices will always move north, brought the sub-prime crisis in the USA and the subsequent ‘Global Financial Crisis’ and European crisis. The Quantitative Easing policy in advanced economies (AE) created an even more permissive global liquidity. The externality affecting emerging markets (EM) took the form of massive capital inflows, first channelled through banks where the global banks-mostly headquartered in Europe-played a significant role and then through capital market with fund managers being the protagonist. The augmented liquidity spurred growth in EM but also elevated the risk of financial instability. Capital flows reversal, slower growth and less benign external conditions have put EM in a quandary. The uncertainty is heightened by a non-synchronised monetary policy in AE (‘Great Divergence’). To the extent that standard policies have become ineffective, and to defend from externality caused by AE's unilateral policy (financial nationalism), it is argued that EM can put a damper on the dangerous component of capital inflows. As part of macroprudential policy, such a measure is equivalent with discouraging risky behaviour to prevent financial instability and worsening income inequality.
      PubDate: 2016-11-24T00:26:05.341052-05:
      DOI: 10.1111/apel.12155
  • Trade openness and income inequality in China and the SAARC Region
    • Authors: Muhammad Zakaria; Bashir Ahmed Fida
      Pages: 33 - 44
      Abstract: The paper empirically examines the effects of trade liberalisation on income inequality in China and the South Asian Association for Regional Cooperation countries. Panel data analysis is conducted for the period of 1973 to 2012. The results show that liberal trade policies have increased income inequality in these countries. These results are robust to alternative liberalisation measures. The control variables used have differing effects on income distribution. Per capita income has an increasing effect on income inequality, while education, financial development, financial openness, democracy, and government size are shown to reduce income inequality. These outcomes can be expected to have important policy implications for the use of trade liberalisation in these countries.
      PubDate: 2016-11-24T00:26:06.567423-05:
      DOI: 10.1111/apel.12152
  • Union relevance in the Malaysian labour market
    • Authors: Hazrul Shahiri; Zulkifly Osman, Kihong Park
      Pages: 45 - 56
      Abstract: The study estimates the effect of union membership on workers' wages using individual-level data from a survey conducted among employees in various sectors in Malaysia in 2012. Initial results show that union membership has a positive effect on wages. However, after controlling for endogeneity, union membership or the presence of a labour union within a firm is not statistically significant for individual wage levels. Because there is no trade union wage premium, the study suggests that the revival of labour union membership is not going to be an easy task.
      PubDate: 2016-11-24T00:26:07.119338-05:
      DOI: 10.1111/apel.12153
  • Understanding FDI and production networks in East Asia
    • Authors: Willem Thorbecke; Nimesh Salike
      Pages: 57 - 71
      Abstract: We provide evidence from the electronics industry in East Asia supporting Kojima's (1973) hypothesis that FDI moves from capital-exporting countries' disadvantaged industries into host countries' advantaged industries. These results imply that FDI and trade are complementary, unlike in Mundell's (1957) model where they are substitutes. The results also indicate that exchange rate volatility deters trade, implying that reductions in the service link costs between production blocks can promote fragmentation. These findings imply that host countries in East Asia can receive technology transfers by lowering service link costs.
      PubDate: 2016-11-24T00:26:04.650625-05:
      DOI: 10.1111/apel.12147
  • Assessing the trade impacts of the ASEAN + 6 FTA for Lao PDR
    • Authors: Sithanonxay Suvannaphakdy; Hsiao Chink Tang, Alisa DiCaprio
      Pages: 72 - 89
      Abstract: Using an unbalanced panel dataset of bilateral exports from 1992 to 2009, we assess the potential trade impacts of the expansion of the Association of Southeast Asian Nations (ASEAN) to ASEAN + 3 and ASEAN + 6 on the Lao People's Democratic Republic (Lao PDR). It is found that bilateral exports are positively related to overall bilateral country size and similarity in country size but inversely related to the factor endowment differences, transportation costs, and import tariffs. Simulation results show that the formation of preferential trade agreements (PTAs) between ASEAN and the Plus-6 economies (the People's Republic of China, Japan, and the Republic of Korea in East Asia; and the other three economies of Australia, India, and New Zealand) could increase bilateral trade between the Lao PDR and ASEAN + 6 by US$1 billion, and ASEAN + 3 by US$981 million. Nonetheless, the trade balance of the Lao PDR is likely to worsen in both the ASEAN + 3 and ASEAN + 6 PTAs because they stimulate more imports than exports.
      PubDate: 2016-11-24T00:26:04.12498-05:0
      DOI: 10.1111/apel.12148
  • From share issue privatisation to non-tradable share reform: a review of
           privatisation in China
    • Authors: Feng Xie; Jing Chi, Jing Liao
      Pages: 90 - 104
      Abstract: Privatisation in China has proceeded on a gradual path over 30 years. In this paper, we present a detailed review of China's privatisation programmes from its Share Issue Privatisation (SIP) to its Non-tradable Share (NTS) reform. The SIP was a primary offering process with state-owned enterprises (SOEs) issuing new shares to private investors, but after their Initial Public Offering (IPO) approximately two-thirds of the shares remained non-tradable and were mainly held by the government. The SIP achieved only limited success because of its partial trading and partial privatisation, which led to the implementation of the NTS reform in 2005. The NTS reform aimed to dismantle the split share structure and provide opportunities for improving corporate governance and further privatisation. The review shows that the NTS reform has yielded greater success in improving firm performance and corporate governance than the SIP.
      PubDate: 2016-11-24T00:26:07.537362-05:
      DOI: 10.1111/apel.12149
  • Connecting Asia: Infrastructure for Integrating South and Southeast Asia
           Michael G. Plummer, Peter J. Morgan, and Ganeshan Wignaraja (eds) Edward
           Elgar, Cheltenham, UK, 2016 Pp. 395 + xv. ISBN 978 1 78536 347 4
    • Authors: Douglas H. Brooks
      Pages: 105 - 106
      PubDate: 2016-11-24T00:26:05.07009-05:0
      DOI: 10.1111/apel.12156
  • Land and Development in Indonesia: Searching for the Peoples' Sovereignty
           J.F. McCarthy and K. Robinson (eds) Institute of Southeast Asian Studies,
           Singapore, 2016 P. 395. ISBN: 978-981-47-6209-0
    • Authors: Ian Coxhead
      Pages: 106 - 108
      PubDate: 2016-11-24T00:26:06.176897-05:
      DOI: 10.1111/apel.12157
  • Understanding Development Economics. Adam Fforde Routledge, London and New
           York, 2013 Pp. 354. ISBN: 978-0-415-86982-9
    • Authors: Dilip K. Das
      Pages: 108 - 109
      PubDate: 2016-11-24T00:26:05.165972-05:
      DOI: 10.1111/apel.12158
  • Socioeconomic Development A. Szirmai (Second Edition) Cambridge University
           Press, 2015 Pp. 763 + xxx. ISBN: 0-521-81763-3
    • Authors: Emmanuel S. Dios
      Pages: 109 - 111
      PubDate: 2016-11-24T00:26:05.237362-05:
      DOI: 10.1111/apel.12159
  • Moving the AEC Beyond 2015: Managing Domestic Consensus for Community
           Building Tham Siew Yean and Sanchita Basu Das (eds) Institute of Southeast
           Asian Studies, Singapore, 2016 Pp. 211. ISBN: 978-981-4695-51-0 ASEAN
           Economic Community: A Model for Asia-Wide Regional Integration' Bruno
           Jetin and Mia Mikic (eds) Palgrave Macmillan, UK, 2016 Pp. 350. ISBN:
    • Authors: Evelyn S. Devadason
      Pages: 111 - 112
      PubDate: 2016-11-24T00:26:08.075873-05:
      DOI: 10.1111/apel.12160
  • Macro-financial Linkages in the Pacific Region Akira Kohsaka (ed)
           Routledge, 2015 P. 284. ISBN: 9781138806535
    • Authors: Mardi Dungey
      Pages: 113 - 114
      PubDate: 2016-11-24T00:26:08.270963-05:
      DOI: 10.1111/apel.12161
  • The Myanmar Economy: Its Past, Present, and Prospects Konosuke Odaka (ed)
           Springer, 2016 Pp. 239. ISBN 13:9784431557340
    • Authors: Ronald Findlay
      Pages: 114 - 115
      PubDate: 2016-11-24T00:26:07.882771-05:
      DOI: 10.1111/apel.12162
  • The Evolving Sphere of Food Security Rosamond L. Naylor (ed) Oxford
           University Press, New York, 2014 P. 416. ISBN: 9780199354061
    • Authors: Quentin Grafton
      Pages: 115 - 117
      PubDate: 2016-11-24T00:26:06.274583-05:
      DOI: 10.1111/apel.12163
  • The Yudhoyono Presidency: Indonesia's Decade of Stability and Stagnation
           Edward Aspinall, Marcus Mietzner, and Dirk Tomsa (eds) ISEAS Publishing,
           Institute of Southeast Asian Studies, Singapore, 2015 P. 362. ISBN
    • Authors: R. William Liddle
      Pages: 117 - 119
      PubDate: 2016-11-24T00:26:08.164879-05:
      DOI: 10.1111/apel.12164
  • The Price of Oil Roberto F Aguilera and Marian Radetzki Cambridge
           University Press, Cambridge, 2016 P. 242. ISBN: 9781107110014
    • Authors: Philip Maxwell
      Pages: 119 - 120
      PubDate: 2016-11-24T00:26:06.048163-05:
      DOI: 10.1111/apel.12165
  • Strengthening Social Protection in East Asia Mukul G. Asher and F. Kimura
           (eds) Taylor and Francis, London P. 258. ISBN: 9781317510666
    • Authors: Riyana Miranti
      Pages: 120 - 121
      PubDate: 2016-11-24T00:26:06.365798-05:
      DOI: 10.1111/apel.12166
  • Development and Modern Industrial Policy Practice: Issues and Country
           Experiences Jesus Felipe (ed) Asian Development Bank and Edward Elgar
           Publishing, 2015 P. 406. ISBN: 978784715533
    • Authors: Patarapong Intarakumnerd
      Pages: 121 - 123
      PubDate: 2016-11-24T00:26:04.029383-05:
      DOI: 10.1111/apel.12167
  • Mineral Economics and Policy J E Tilton and J I Guzmán RFF Press, New
           York City, 2016 Pp. 255. ISBN: 978-1-138-83895-6
    • Authors: Marian Radetzki
      Pages: 123 - 124
      PubDate: 2016-11-24T00:26:07.003108-05:
      DOI: 10.1111/apel.12168
  • Australia's Indonesia Project: 50 Years of Engagement Colin Brown Bobby
           Graham Publishers, Manuka, 2015 Pp. 128. ISBN: 978-0-9874041-4-5
    • Authors: Christian Lübke
      Pages: 125 - 127
      PubDate: 2016-11-24T00:26:07.978608-05:
      DOI: 10.1111/apel.12170
  • Partners and Rivals: The Uneasy Future of China's Relationship with the
           United States Wendy Dobson University of Toronto Press, 2013 Pp. 136.
           ISBN: 978-1-4426-4752-7
    • Authors: James Riedel
      Pages: 125 - 125
      PubDate: 2016-11-24T00:26:03.935331-05:
      DOI: 10.1111/apel.12169
  • Education Matters: Global Schooling Gains from the 19th to the 21st
           Century Robert J. Barro and Jong-Wha Lee Oxford University Press, New
           York, 2015 P. 304. ISBN: 13:9780199379231
    • Authors: Glenn Withers
      Pages: 127 - 128
      PubDate: 2016-11-24T00:26:04.990618-05:
      DOI: 10.1111/apel.12171
  • Erratum
    • Pages: 129 - 131
      PubDate: 2016-11-24T00:26:06.440646-05:
      DOI: 10.1111/apel.12154
  • Contents: Astron. Nachr. 10/2016
    • Pages: 995 - 1000
      PubDate: 2016-11-29T03:06:41.220529-05:
      DOI: 10.1002/asna.201605010
  • Editors' note: Astron. Nachr. 10/2016
    • Authors: Rohan Eugene Louis; Gottfried Mann, Carsten Denker
      Pages: 1001 - 1001
      PubDate: 2016-12-16T04:58:31.385291-05:
      DOI: 10.1002/asna.201690020
  • Editors' note: Astron. Nachr. 10/2016
    • Authors: Rohan Eugene Louis; Gottfried Mann, Carsten Denker
      Pages: 1001 - 1001
      PubDate: 2016-11-29T03:06:41.131563-05:
      DOI: 10.1002/asna.201690017
  • Solar eruptions: The CME-flare relationship
    • Authors: B. Vršnak
      Pages: 1002 - 1009
      Abstract: Coronal mass ejections (CMEs), caused by large-scale eruptions of the coronal magnetic field, often are accompanied by a more localized energy release in the form of flares, as a result of dissipative magnetic-field reconfiguration. Morphology and evolution of such flares, also denoted as dynamical flares are often explained as a consequence of reconnection of the arcade magnetic field, taking place below the erupting magnetic flux rope. A close relationship of the CME acceleration and the flare energy release is evidenced by various statistical correlations between parameters describing CMEs and flares, as well as by the synchronization of the CME acceleration phase with the impulsive phase of the associated flare. Such behavior implies that there must be a feedback relation between the dynamics of the CME and the flare-associated reconnection process. From the theoretical standpoint, magnetic reconnection affects the CME dynamics in several ways. First, it reduces the tension of the overlying arcade magnetic field and increases the magnetic pressure below the flux rope, and in this way enhances the CME acceleration. Furthermore, it supplies the poloidal magnetic flux to the flux rope, which helps sustaining the electric current in the rope and prolonging the action of the driving Lorentz force to large distances. The role of these processes, directly relating solar flares and CMEs, is illustrated by employing a simple model, where the erupting structure is represented by a curved flux rope anchored at both sides in the dense/inert photosphere, being subject to the kink and torus instability. It is shown that in most strongly accelerated ejections, where values on the order of 10km s–2 are attained, the poloidal flux supplied to the erupting rope has to be several times larger than was the initial flux. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2016-11-29T03:06:41.349042-05:
      DOI: 10.1002/asna.201612424
  • Kinematical properties of coronal mass ejections
    • Authors: M. Temmer
      Pages: 1010 - 1015
      Abstract: Coronal mass ejections (CMEs) are the most dynamic phenomena in our solar system. They abruptly disrupt the continuous outflow of solar wind by expelling huge clouds of magnetized plasma into interplanetary space with velocities enabling to cross the Sun-Earth distance within a few days. Earth-directed CMEs may cause severe geomagnetic storms when their embedded magnetic fields and the shocks ahead compress and reconnect with the Earth's magnetic field. The transit times and impacts in detail depend on the initial CME velocity, size, and mass, as well as on the conditions and coupling processes with the ambient solar wind flow in interplanetary space. The observed CME parameters may be severely affected by projection effects and the constant changing environmental conditions are hard to derive. This makes it difficult to fully understand the physics behind CME evolution, preventing to do a reliable forecast of Earth-directed events. This short review focusing on observational data, shows recent methods which were developed to derive the CME kinematical profile for the entire Sun-Earth distance range as well as studies which were performed to shed light on the physical processes that CMEs encounter when propagating from Sun to Earth. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2016-11-29T03:06:39.623275-05:
      DOI: 10.1002/asna.201612425
  • Plasma diagnostics in two kinematic classes of CMEs observed by the
           Atmospheric Imaging Assembly onboard the Solar Dynamic Observatory
    • Authors: E. Chmielewska; M. Tomczak, S. Kołomański, T. Mrozek
      Pages: 1016 - 1019
      Abstract: In order to study the dynamics and thermal properties of two kinematic classes of coronal mass ejections (CMEs) we analyzed two well-observed events in the early stage of their propagation, using multiwavelength observations from the Atmospheric Imaging Assembly (AIA) of the Solar Dynamic Observatory (SDO). For deriving differential emission measure (DEM) profiles and DEM maps of the basic structures of CMEs, we used two methods: the regularized inversion and the iterative forward–fitting approach. For the CME associated with a M2.0 class flare (CME-FL), we identified a hot, moving, blob-like feature which seems to be a candidate for a CME flux rope. Furthermore, an expanding system of loop and coronal dimming was clearly seen in AIA images. For the CME related to an eruptive prominence (CME–EP), we observed an eruptive plasmoid and a failed-eruption of cold plasma. However, we also recognized warm and hot moving signatures that revealed a multi-temperature nature of the eruptive prominence. Our main results are as follows: (a) An analysis of the examples of the two different kinematic classes of CMEs shows that despite the slight variations in the values of speeds and accelerations (CME-FL: v ≈ 174 km s–1, a ≈ 350 ms–2; CME-EP: v ≈ 135 km s–1, a ≈ 160 ms–2) they present the same kinematic behavior; (b) in the field of view of the LASCO coronagraphs these two events have the similar, positive accelerations; (c) for both events we observed an impulsive acceleration phase (IAP); (d) the expanding structures seen in 171 Å, 193 Å, 211 Å in both events move faster than the hotter blobs; (e) the plasmoid core for the CME-FL is hot (8.0–15.8 MK); (f) the expanding blob and the hot structure in the prominence region for the CME–EP event have the similar temperature range (0.8–2.5 MK). (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2016-11-29T03:06:41.627313-05:
      DOI: 10.1002/asna.201612426
  • Hybrid simulations of chromospheric HXR flare sources
    • Authors: Z. Moravec; M. Varady, J. Kašparová, D. Kramoliš
      Pages: 1020 - 1023
      Abstract: Recent measurements of vertical extents and positions of the chromospheric hard X-ray (HXR) flare sources based on Ramaty High-Energy Spectroscopic Imager (RHESSI) observations show a significant inconsistency with the theoretical predictions based on the standard collisional thick target model (CTTM). Using the hybrid flare code Flarix, we model simultaneously and self-consistently the propagation, scattering and energy losses of electron beams with power-law energy spectra and various initial pitch-angle distributions in a purely collisional approximation and concurrently the dynamic response of the heated chromosphere on timescales typical for RHESSI image reconstruction. The results of the simulations are used to model the time evolution of the vertical distribution of chromospheric HXR source within a singular (compact) loop. Adopting the typical RHESSI imaging times scales, energy dependent vertical sizes and positions as could be observed by RHESSI are presented. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2016-11-29T03:06:40.773687-05:
      DOI: 10.1002/asna.201612427
  • Observations of solar X-ray and EUV jets and their related phenomena
    • Authors: D. E. Innes; R. Bučík, L.-J. Guo, N. Nitta
      Pages: 1024 - 1032
      Abstract: Solar jets are fast-moving, elongated brightenings related to ejections seen in both images and spectra on all scales from barely visible chromospheric jets to coronal jets extending up to a few solar radii. The largest, most powerful jets are the source of type III radio bursts, energetic electrons and ions with greatly enhanced 3He and heavy element abundances. The frequent coronal jets from polar and equatorial coronal holes may contribute to the solar wind. The primary acceleration mechanism for all jets is believed to be release of magnetic stress via reconnection; however the energy buildup depends on the jets' source environment. In this review, we discuss how certain features of X-ray and EUV jets, such as their repetition rate and association with radio emission, depends on their underlying photospheric field configurations (active regions, polar and equatorial coronal holes, and quiet Sun). (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2016-11-29T03:06:40.095684-05:
      DOI: 10.1002/asna.201612428
  • Chromospheric activity in sunspot light bridges
    • Authors: R. E. Louis
      Pages: 1033 - 1039
      Abstract: High-resolution filtergrams from Hinode were used to analyse the nature of chromospheric activity over a set of five sunspot light bridges. The broad-band Ca II H filtergrams depict a variety of phenomena which include large arc-shaped brightenings, bright patches, and small-scale jets. These strong brightenings are recurrent over a duration of several hours and appear to be a common attribute of a sunspot light bridge, independent of its photospheric morphology and horizontal flow pattern. Hinode spectro-polarimetric observations were used to construct far wing magnetograms from the Fe I line at 630.25 nm, which reveal the presence of small-scale magnetic and velocity inhomogeneities in the photosphere of the light bridges. Although there is strong evidence for a causal relation between the photospheric anomalies and the observed chromospheric activity, the physical mechanism responsible for the latter remains speculative. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
      PubDate: 2016-11-29T03:06:40.601624-05:
      DOI: 10.1002/asna.201612429
  • Magnetic field reconstruction based on sunspot oscillations
    • Authors: J. Löhner-Böttcher; N. Bello González, W. Schmidt
      Pages: 1040 - 1044
      PubDate: 2016-11-29T03:06:39.914391-05:
      DOI: 10.1002/asna.201612430
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