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arXiv 2017年

作者： Kang, Xiaoyu Zhang, Fenghui Chang, Ruixiang Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences 80 Nandan Road Shanghai200030 China

NGC 2403, NGC 300 and M33 are three nearby pure-disc galaxies with similar stellar mass in different environments, they are benchmarks for understanding late-type spiral galaxies in different environments. The chemical evolution and growth of their discs are investigated by using the simple chemical evolution model, in which their discs are assumed to originate and grow through the accretion of the primordial gas, and the gas outflow process is also taken into account. Through comparative study of the best-fitting model predicted star formation histories for them, we hope to derive a picture of the local environment on the evolution and star formation histories of galaxies and whether or not the isolated galaxies follow similar evolution history. Our results show that these three galaxies accumulated more than 50 percent of their stellar mass at z 25−1. The similar metallicity gradients in NGC 2403 and NGC 300 indicate that they may experience similar chemical evolutionary histories. The principal epoch of star formation on the discs of NGC 2403 and NGC 300 is earlier than that on the disc of M33, and the mean age of stellar populations along the discs of both NGC 2403 and NGC 300 is older than that of M33. Our results indicates that the evolution and star formation history of a galaxy indeed depends on its local environment, at least for galaxies with stellar mass of 109.2 M ∼ 109.7 M. Copyright © 2017, The Authors. All rights reserved.

关键词： Galaxies

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Discovery of two new hypervelocity stars from the lamost spectroscopic surveys

arXiv

引用

arXiv 2017年

作者： Huang, Y. Liu, X.-W. Zhang, H.-W. Chen, B.-Q. Xiang, M.-S. Wang, C. Yuan, H.-B. Tian, Z.-J. Li, Y.-B. Wang, B. South-Western Institute for Astronomy Research Yunnan University Kunming650500 China Department of Astronomy Peking University Beijing100871 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China Department of Astronomy Beijing Normal University Beijing100875 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing100012 China Key Laboratory for the Structure and Evolution of Celestial Objects Yunnan Observatories CAS Kunming650216 China LAMOST Fellow

We report the discovery of two new unbound hypervelocity stars (HVSs) from the LAMOST spectroscopic surveys. They are respectively a B2V type star of ∼ 7 Mowith a Galactic rest-frame radial velocity of 502 km s-1at a Galactocentric radius of ∼ 21 kpc and a B7V type star of ∼ 4 Mowith a Galactic rest-frame radial velocity of 408 km s-1at a Galactocentric radius of ∼ 30 kpc. The origins of the two HVSs are not clear given their currently poorly measured proper motions. However, the future data releases of Gaia should provide proper motion measurements accurate enough to solve this problem. The ongoing LAMOST spectroscopic surveys are expected to yield more HVSs to form a statistical sample, providing vital constraint on understanding the nature of HVSs and their ejection mechanisms. Copyright © 2017, The Authors. All rights reserved.

关键词： Stars

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Kerr-anti-de-sitter/de-sitter black hole in perfect fluid dark matter background

arXiv

引用

arXiv 2017年

作者： Xu, Zhaoyi Hou, Xian Wang, Jiancheng Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China

We obtain the Kerr-anti-de-sitter (Kerr-AdS) and Kerr-de-sitter (Kerr-dS) black hole (BH) solutions to the Einstein field equation in the perfect fluid dark matter background using the Newman-Janis method and Mathematica package. We discuss in detail the black hole properties and obtain the following main results: (i) From the horizon equation grr = 0, we derive the relation between the perfect fluid dark matter parameter α and the cosmological constant Λ when the cosmological horizon rΛ exists. For Λ = 0, we find that α is in the range 0 0 and −7.18M max decreases if α > 0, and αmin increases if α max increases if α > 0 and αmin decreases if α 0 and α 0 while is asymptotically flat only when α is close to zero if α Copyright © 2017, The Authors. All rights reserved.

关键词： Gravitation

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Incremental Fermi Large Area Telescope Fourth Source Catalog

arXiv

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arXiv 2022年

作者： Abdollahi, S. Acero, F. Baldini, L. Ballet, Jean Bastieri, D. Bellazzini, R. Berenji, B. Berretta, A. Bissaldi, E. Blandford, R.D. Bloom, E. Bonino, R. Brill, A. Britto, R.J. Bruel, P. Burnett, T.H. Buson, S. Cameron, R.A. Caputo, R. Caraveo, P.A. Castro, D. Chaty, S. Cheung, C.C. Chiaro, G. Cibrario, N. Ciprini, S. Coronado-Blázquez, J. Crnogorcevic, M. Cutini, S. D'Ammando, F. De Gaetano, S. Digel, S.W. Di Lalla, N. Dirirsa, F. Di Venere, L. Domínguez, A. Fallah Ramazani, V. Fegan, S.J. Ferrara, E.C. Fiori, A. Fleischhack, H. Franckowiak, A. Fukazawa, Y. Funk, S. Fusco, P. Galanti, G. Gammaldi, V. Gargano, F. Garrappa, S. Gasparrini, D. Giacchino, F. Giglietto, N. Giordano, F. Giroletti, M. Glanzman, T. Green, D. Grenier, I.A. Grondin, M.-H. Guillemot, L. Guiriec, S. Gustafsson, M. Harding, A.K. Hays, E. Hewitt, J.W. Horan, D. Hou, X. Jóhannesson, G. Karwin, C. Kayanoki, T. Kerr, M. Kuss, M. Landriu, D. Larsson, S. Latronico, L. Lemoine-Goumard, M. Li, J. Liodakis, I. Longo, F. Loparco, F. Lott, B. Lubrano, P. Maldera, S. Malyshev, D. Manfreda, A. Martí-Devesa, G. Mazziotta, M.N. Mereu, I. Meyer, M. Michelson, P.F. Mirabal, N. Mitthumsiri, W. Mizuno, T. Moiseev, A.A. Monzani, M.E. Morselli, A. Moskalenko, I.V. Negro, M. Nuss, E. Omodei, N. Orienti, M. Orlando, E. Paneque, D. Pei, Z. Perkins, J.S. Persic, M. Pesce-Rollins, M. Petrosian, V. Pillera, R. Poon, H. Porter, T.A. Principe, G. Rainò, S. Rando, R. Rani, B. Razzano, M. Razzaque, S. Reimer, A. Reimer, O. Reposeur, T. Sánchez-Conde, M. Saz Parkinson, P.M. Scotton, L. Serini, D. Sgrò, C. Siskind, E.J. Smith, D.A. Spandre, G. Spinelli, P. Sueoka, K. Suson, D.J. Tajima, H. Tak, D. Thayer, J.B. Thompson, D.J. Torres, D.F. Troja, E. Valverde, J. Wood, K. Zaharijas, G. IRAP Université de Toulouse CNRS UPS CNES ToulouseF-31028 France Université Paris Saclay Université Paris Cité CEA CNRS AIM Gif-sur-Yvette F-91191 France Università di Pisa Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy Istituto Nazionale di Fisica Nucleare Sezione di Padova PadovaI-35131 Italy Dipartimento di Fisica e Astronomia "G. Galilei" Università di Padova PadovaI-35131 Italy Center for Space Studies and Activities "G. Colombo" University of Padova Via Venezia 15 PadovaI-35131 Italy Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy California State University Los Angeles Department of Physics and Astronomy Los AngelesCA90032 United States Dipartimento di Fisica Università degli Studi di Perugia PerugiaI-06123 Italy Dipartimento di Fisica "M. Merlin" Università e del Politecnico di Bari via Amendola 173 BariI-70126 Italy Istituto Nazionale di Fisica Nucleare Sezione di Bari BariI-70126 Italy W. W. Hansen Experimental Physics Laboratory Kavli Institute for Particle Astrophysics and Cosmology Department of Physics SLAC National Accelerator Laboratory Stanford University StanfordCA94305 United States Istituto Nazionale di Fisica Nucleare Sezione di Torino TorinoI-10125 Italy Dipartimento di Fisica Università degli Studi di Torino TorinoI-10125 Italy NASA Postdoctoral Program NASA Goddard Space Flight Center GreenbeltMD20771 United States Department of Physics University of the Free State P.O. Box 339 Bloemfontein9300 South Africa Laboratoire Leprince-Ringuet École Polytechnique CNRS IN2P3 PalaiseauF-91128 France Department of Physics University of Washington SeattleWA98195-1560 United States Institut für Theoretische Physik and Astrophysik Universität Würzburg WürzburgD-97074 Germany NASA Goddard Space Flight Center GreenbeltMD20771 United States INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano via E. Bassini 15 MilanoI-20133 Italy Harvard-Smithsoni

We present an incremental version (4FGL-DR3, for Data Release 3) of the fourth Fermi-LAT catalog of γ-ray sources. Based on the first twelve years of science data in the energy range from 50 MeV to 1 TeV, it contains 6658 sources. The analysis improves on that used for the 4FGL catalog over eight years of data: more sources are fit with curved spectra, we introduce a more robust spectral parameterization for pulsars, and we extend the spectral points to 1 TeV. The spectral parameters, spectral energy distributions, and associations are updated for all sources. Light curves are rebuilt for all sources with 1 yr intervals (not 2 month intervals). Among the 5064 original 4FGL sources, 16 were deleted, 112 are formally below the detection threshold over 12 yr (but are kept in the list), while 74 are newly associated, 10 have an improved association, and seven associations were withdrawn. Pulsars are split explicitly between young and millisecond pulsars. Pulsars and binaries newly detected in LAT sources, as well as more than 100 newly classified blazars, are reported. We add three extended sources and 1607 new point sources, mostly just above the detection threshold, among which eight are considered identified, and 699 have a plausible counterpart at other wavelengths. We discuss the degree-scale residuals to the global sky model and clusters of soft unassociated point sources close to the Galactic plane, which are possibly related to limitations of the interstellar emission model and missing extended sources. © 2022, CC BY.

关键词： Pulsars

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Search for intra-day optical variability in Mrk 501

arXiv

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arXiv 2017年

作者： Feng, Hai-Cheng Liu, H.T. Fan, X.L. Zhao, Yinghe Bai, J.M. Wang, Fang Xiong, D.R. Li, S.K. Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China

We present our observations of the optical intra-day variability (IDV) in γ-ray BL Lac object Mrk 501. The observations were run with the 1.02 m and 2.4 m optical telescopes at Yunnan Observatories from 2005 April to 2012 May. The light curve at the R band on 2010 May 15 passes both variability tests (the F test and the ANOVA test). A flare within the light curve on 2010 May 15 has a magnitude change ∆m = 0.03±0.005stat±0.007sys mag, a darkening timescale of τd = 26.7 minutes, and an amplitude of IDV Amp = 2.9%±0.7%. A decline described by 11 consecutive flux measurements within the flare can be fitted linearly with a Pearson’s correlation coefficient r = 0.945 at the confidence level of > 99.99%. Under the assumptions that the IDV is tightly connected to the mass of the black hole, and that the flare duration, being two times τd, is representative of the minimum characteristic timescale, we can derive upper bounds to the mass of the black hole. In the case of the Kerr black hole, the timescale of ∆tobmin = 0.89 hours gives M• . 109.20M☉, which is consistent with measurements reported in the literature. This agreement indicates that the hypothesis about M• and ∆tobmin is consistent with the measurements/data. Copyright © 2017, The Authors. All rights reserved.

关键词： Galaxies

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Erratum: 'A Mixture evolution Scenario of the AGN Radio Luminosity Function. II. Do Low- and High-power Radio-loud AGNs Evolve Differently?' (2017, ApJ, 846, 78)

引用

The Astrophysical Journal 2018年第2期865卷

作者： Zunli Yuan Jiancheng Wang Ming Zhou Longhua Qin Jirong Mao Yunnan Observatories Chinese Academy of Sciences Kunming 650216 People's Republic of China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing 100012 People's Republic of China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650216 People's Republic of China University of Chinese Academy of Sciences Beijing 100049 People's Republic of China

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Kerr-Newman-AdS black hole surrounded by scalar field matter in rastall gravity

arXiv

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arXiv 2017年

作者： Xu, Zhaoyi Wang, Jiancheng Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China

Rastall gravity is the modify Einstein general relativity, in which the energy-momentum conservation is assumed to be unsatisfied and generalized to T µν;µ = λR,ν. In this paper we investigate the Kerr-Newman-AdS black hole solutions surrounded by the scalar field matter of the Einstein-Maxwell equation in Rastall gravity using Newman-Jains method and complex computations. Through analyzing the root numbers of the horizon equation for two situations, we obtain the relations of α, M and κλ. For the quintessence dark energy (ω = −2/3), if 0 Copyright © 2017, The Authors. All rights reserved.

关键词： Gravitation

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Multi-color light curves and orbital period research of eclipsing binary V1073 Cyg

arXiv

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arXiv 2017年

作者： Tian, Xiao-man Zhu, Li-ying Qian, Sheng-bang Li, Lin-jia Jiang, Lin-qiao P. O. Box 110 Kunming650216 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences P. O. Box 110 Kunming650216 China University of the Chinese Academy of Science Yuquan Road 19 Sijingshang Block Beijing100049 China School of Physics and Electronic Engineering Sichuan University of Science & Engineering Zigong643000 China

New Multi-color B V Rc Ic photometric observation are presented for W UMa type eclipsing binary V1073 Cyg. The multi-color light curves analysis with the Wilson-Devinney(W-D) procedure acquired the absolute parameters of this system, showing that V1073Cyg is a shallow contact binary system with fill-out factor f = 0.124(±0.011). We collected all available times of light minima spanning 119 years including CCD data to construct the O-C curve and made detailed O-C analysis. The O-C diagram shows that the period change is complex. There exist a long-term continuous decrease and a cyclic variation. The period is decreasing at a rate of P = −1.04(±0.18) × 10−10days · cycle−1, and with the period decrease, V1073 Cyg will evolve to deep contact stage. The cyclic variation with a period of P3 = 82.7(±3.6)years and an amplitude of A = 0.028(±0.002)day may be explained by the magnetic activity of one or both components or the light travel time effect (LTTE) caused by a distant third companion with M3(i′ = 90◦) = 0.511M. Copyright © 2017, The Authors. All rights reserved.

关键词： Stars

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SDSS J012119.10 001949.9:a very short period M dwarf contact binary from SDSS stripe 82

引用

Research in Astronomy and Astrophysics 2015年第12期15卷 2237-2243页

作者： Lin-Qiao Jiang Sheng-Bang Qian Jia Zhang Yunnan Observatories Chinese Academy of Sciences Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences University of Chinese Academy of Sciences

We present the first multicolor photometric observations of the short period low-mass eclipsing binary SDSS J012119.10-4301949.9. By using the 2013 version of the Wilson-Devinney code, the photometric solutions are derived. It is found that the system is in a contact configuration （f = 18.9± 6.0%） with a moderate mass ratio of 0.5 ± 0.01. A third light contributing about 6.1± 1.3% of the total luminosity in the V band was found, which may come from a cool tertiary component. The derived high orbital inclination （i - 83.9°± 0.5°） and the almost symmetric three light curves suggest that the determined parameters are reliable. Both the color class and spectral class of the system correspond to a spectral type of M0, which may indicate that SDSS J012119.10-001949.9 belongs to a very rare class of M dwarf contact binaries that are below the theoretical short period limit.

关键词： binaries： eclipsing -- stars： individual （SDSS J012119.10-001949.9） --techniques： photometric

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Double cyclic variations in orbital period of the eclipsing cataclysmic variable EX Dra

arXiv

引用

arXiv 2017年

作者： Han, Zhong-Tao Qian, Sheng-Bang Voloshina, Irina Zhu, Li-Ying P. O. Box 110 Kunming650216 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences P. O. Box 110 Kunming650216 China University of Chinese Academy of Sciences Yuquan Road 19# Sijingshang Block Beijing100049 China Sternberg Astronomical Institute Moscow State University Universitetskij prospect 13 Moscow119992 Russia

EX Dra is a long-period eclipsing dwarf nova with ~ 2 - 3 mag amplitude outbursts. This star has been monitored photometrically from November, 2009 to March, 2016 and 29 new mid-eclipse times were obtained. By using new data together with the published data, the best fit to the O - C curve indicate that the orbital period of EX Dra have an upward parabolic change while undergoing double-cyclic variations with the periods of 21.4 and 3.99 years, respectively. The upward parabolic change reveals a longterm increase at a rate of P = +7.46×10-11ss-1. The evolutionary theory of cataclysmic variables (CVs) predicts that, as a CV evolves, the orbital period should be decreasing rather than increasing. Secular increase can be explained as the mass transfer between the secondary and primary or may be just an observed part of a longer cyclic change. Most plausible explanation for the double-cyclic variations is a pair of light travel-time effect via the presence of two companions. Their masses are determined to be MAsini' A= 29.3(±0.6)MJupand MBsini'B= 50.8(±0.2)MJup. When the two companions are coplanar to the orbital plane of the central eclipsing pair, their masses would match to brown dwarfs. Copyright © 2017, The Authors. All rights reserved.

关键词： Stars

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