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arXiv 2019年

作者： Bostroem, K.A. Valenti, S. Sand, D.J. Andrews, J.E. Van Dyk, S.D. Galbany, L. Pooley, D. Amaro, R.C. Smith, N. Yang, S. Anupama, G.C. Arcavi, I. Baron, E. Brown, P.J. Burke, J. Cartier, R. Hiramatsu, D. Dastidar, R. Derkacy, J.M. Dong, Y. Egami, E. Ertel, S. Filippenko, A.V. Fox, O.D. Haislip, J. Hosseinzadeh, G. Howell, D.A. Gangopadhyay, A. Jha, S.W. Kouprianov, V. Kumar, B. Lundquist, M. Milisavljevic, D. McCully, C. Milne, P. Misra, K. Reichart, D.E. Sahu, D.K. Sai, H. Singh, A. Smith, P.S. Vinko, J. Wang, X. Wang, Y. Wheeler, J.C. Williams, G.G. Wyatt, S. Zhang, J. Zhang, X. Department of Physics University of California 1 Shields Avenue DavisCA95616-5270 United States University of Arizona Steward Observatory 933 North Cherry Avenue TucsonAZ85721-0065 United States Caltech/IPAC Mailcode 100-22 PasadenaCA91125 United States Departamento de Fsica Terica y Del Cosmos Universidad de Granada GranadaE-18071 Spain Department of Physics and Astronomy Trinity University San AntonioTX United States Eureka Scientific Inc. United States Department of Physics and Astronomy Galileo Galilei University of Padova Vicolo dell'Osservatorio 3 PadovaI-35122 Italy INAF-Osservatorio Astronomico di Padova Vicolo dell'Osservatorio 5 PadovaI-35122 Italy Indian Institute of Astrophysics Koramangala 2nd Block Bengaluru560 034 India School of Physics and Astronomy Tel Aviv University Tel Aviv69978 Israel Homer L. Dodge Department of Physics and Astronomy University of Oklahoma NormanOK United States Mitchell Institute for Fundamental Physics and Astronomy Texas A and M University College StationTX77843 United States Department of Physics University of California Santa BarbaraCA93106-9530 United States Las Cumbres Observatory 6740 Cortona Dr Suite 102 GoletaCA93117-5575 United States Cerro Tololo Inter-American Observatory National Optical Astronomy Observatory Casilla 603 La Serena Chile Aryabhatta Research Institute of Observational Sciences Manora Peak Nainital263 001 India Department of Physics and Astrophysics University of Delhi Delhi110 007 India Large Binocular Telescope Observatory 933 North Cherry Avenue TucsonAZ85721 United States Department of Astronomy University of California BerkeleyCA94720-3411 United States Miller Institute for Basic Research in Science University of California Miller Senior Fellow BerkeleyCA94720 United States Space Telescope Science Institute 3700 San Martin Drive BaltimoreMD21218 United States Department of Physics and Astronomy University of North Carolina at Chapel Hill Chape

We present the discovery and high-cadence follow-up observations of SN 2018ivc, an unusual Type II supernova that exploded in NGC 1068 (D = 10:1 Mpc). The light curve of SN 2018ivc declines piecewise-linearly, changing slope frequently, with four clear slope changes in the first 40 days of evolution. This rapidly changing light curve indicates that interaction between the circumstellar material and ejecta plays a significant role in the evolution. Circumstellar interaction is further supported by a strong X-ray detection. The spectra are rapidly evolving and dominated by hydrogen, helium, and calcium emission lines. We identify a rare high-velocity emission-line feature blueshifted at 7800 km s1 (in H, H, P, P, He i, Ca ii), which is visible from day 18 until at least day 78 and could be evidence of an asymmetric progenitor or explosion. From the overall similarity between SN 2018ivc and SN 1996al, the H equivalent width of its parent Hii region, and constraints from pre-explosion archival Hubble Space Telescope images, we find that SN 2018ivc may have had a high-mass progenitor (with initial mass & 25M). SN 2018ivc demonstrates the importance of the early discovery and rapid follow-up observations of nearby supernovae to study the physics and progenitors of these cosmic explosions. Copyright © 2019, The Authors. All rights reserved.

关键词： Supernovae

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Binary stars on the galaxy SFH

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Proceedings of the International Astronomical Union 2016年第S315期11卷 E86-E86页

作者： F. Zhang L. Li Z. Han Yunnan Observatories Chinese Academy of Sciences Kunming 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China email: zhangfh@***

Using the Yunnan-II evolutionary population synthesis models comprising binary stars, we find that the inclusion of binary stars can raise the derived stellar metallicity Z* and/or age t (degeneracy problem), raise the stellar mass M*, lower the gaseous metallicity Zgas and star formation rate (SFR) of galaxies. This means that a few stars form recently in galaxies, while more stars form during the entire evolution process when considering binary stars. If the degeneracy between t and Z* can be broken, its effect on the feedback process and star formation history can be determined.

关键词： (stars:) binaries: general galaxies: evolution

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Photometric study of three ultrashort-period contact binaries

arXiv

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arXiv 2017年

作者： Liu, L. Qian, S.-B. Fernández Lajús, E. Essam, A. El-Sadek, M.A. Xiong, X. 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 University of Chinese Academy of Sciences Yuquan Road 19# Sijingshang Block Beijing100049 China Facultad de Ciencias Astronómicas y Geofísicas Universidad Nacional de La Plata Buenos Aires La Plata1900 Argentina Instituto de Astrofísica de La Plata CCT La Plata-CONICET UNLP Argentina Complejo Astronómico El Leoncito Consejo Nacional de Investigaciones Científicas y Técnicas Argentina National Universities of La Plata Córdoba National Research Institute of Astronomy and Geophysics Department of Astronomy Helwan Cairo Egypt

We carried out high-precision photometric observations of three eclipsing ultrashort-period contact binaries (USPCBs). Theoretical models were fitted to the light-curves by means of the Wilson-Devinney code. The solutions suggest that the three targets have evolved to a contact phase. The photometric results are as follows: a) 1SWASP J030749.87−365201.7, q = 0.439 ± 0.003, f = 0.0±3.6 %;b) 1SWASP J213252.93−441822.6, q = 0.560±0.003, f = 14.2±1.9 %;c) 1SWASP J200059.78+054408.9, q = 0.436 ± 0.008, f = 58.4 ± 1.8 %. The light curves show O’Connell effects, which can be modeled by assumed cool spots. The cool spots models are strongly supported by the night-to-night variations in the I-band light curves of 1SWASP J030749.87−365201.7. For a comparative study, we collected the whole set of 28 well-studied USPCBs with P 50 %). Generally, contact binaries with deep fill-out factors are going to merge, but it is believed that USPCBs have just evolved to a contact phase. Hence, the deep USPCB 1SWASPJ200059.78+054408.9 seems to be a contradiction, making it very interesting. Particularly, 1SWASPJ030749.87−365201.7 is a zero contact binary within thermal equilibrium, implying that it should be a turn-off sample as predicted by the thermal relaxation oscillation (TRO) theory. Copyright © 2017, The Authors. All rights reserved.

关键词： Photometry

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Hadronic Scenarios for Gamma-Ray Emission from Three Supernova Remnants Interacting with Molecular Clouds

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Chinese Physics Letters 2014年第4期31卷 206-209页

作者： YU Huan FANG Jun ZHANG Li Department of Physics Yunnan University Kunming 650091 Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011

GeV γ-rays detected with the large area telescope on board the Fermi Gamma-ray space telescope in the direc- tion of HB21, MSH 17-39 and G337.0-0.1 have been recently reported. The three supernova remnants （SNRs） show interactions with molecular clouds, and they are effective gamma-ray emitters as the relativistic protons accelerated by the SNR shocks inelastically colliding with the dense gas in the clouds. The origin of the observed γ-rays for the three remnants is investigated in the scenario of the diffusive shock acceleration. In the model, a part of the SNR shock transmits into the nearby molecular clouds, and the shock velocity is greatly reduced. As a result, a shock with a relatively low Alfven Mach number is generated, and the spectra of the accelerated protons and thee＇γ-ray photons produced via proton-proton interaction can be obtained. The results show that the observed γ-ray spectra for the three SNRs interacting with the molecular clouds can be reproduced. It can be concluded that the hadronic origin of the γ-rays for the three SNRs is approved, and the ability of SNR shocks to accelerate protons is also supported.

关键词： HADRONIC atoms GAMMA-ray absorption SUPERNOVA remnants PROTON-proton interactions PLASMA Alfven waves

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Prompt optical emission from gamma-ray bursts with multiple timescale variability of central engine activities

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Research in Astronomy and Astrophysics 2014年第4期14卷 411-422页

作者： Si-Yao Xu Zhuo Li Department of Astronomy and Kavli Institute for Astronomy and Astrophysics Peking University Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences

Complete high-resolution light curves of GRB 080319B observed by Swift present an opportunity for detailed temporal analysis of prompt optical emission. With a two-component distribution of initial Lorentz factors, we simulate the dynamical process of shells being ejected from the central engine in the framework of the in- ternal shock model. The emitted radiations are decomposed into different frequency ranges for a temporal correlation analysis between the light curves in different energy bands. The resulting prompt optical and gamma-ray emissions show similar tempo- ral profiles, with both showing a superposition of a component with slow variability and a component with fast variability, except that the gamma-ray light curve is much more variable than its optical counterpart. The variability in the simulated light curves and the strong correlation with a time lag between the optical and gamma-ray emis- sions are in good agreement with observations of GRB 080319B. Our simulations suggest that the variations seen in the light curves stem from the temporal structure of the shells injected from the central engine of gamma-ray bursts. Future observations with high temporal resolution of prompt optical emission from GRBs, e.g., by UFFO- Pathfinder and SVOM-GWAC, will provide a useful tool for investigating the central engine activity.

关键词： gamma rays： bursts- GRB 080319B

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The physical constraints on a new lobal QSO at Z = 4.82

arXiv

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arXiv 2017年

作者： Yi, Weimin Green, Richard Bai, Jin-Ming Wang, Tinggui Grier, Catherine J. Trump, Jonathan R. Brandt, William N. Zuo, Wenwen Yang, Jinyi Wang, Feige Yang, Chenwei Wu, Xue-Bing Zhou, Hongyan Fan, Xiaohui Jiang, Linhua Yang, Qian Varricatt, Watson Kerr, Tom Milne, Peter Benigni, Sam Wang, Jian-Guo Zhang, Jujia Wang, Fang Wang, Chuan-Jun Xin, Yu-Xin Fan, Yu-Feng Chang, Liang Zhang, Xiliang Lun, Bao-Li Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Steward Observatory University of Arizona TucsonAZ85721-0065 United States CAS Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Science and Technology of China China Department of Astronomy & Astrophysics Institute for Gravitation & the Cosmos Pennsylvania State University 525 Davey Laboratory University ParkPA16802 United States Hubble Department of Physics University of Connecticut Unit 3046 2152 Hillside Rd StorrsCT06269 United States Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai200030 China Department of Astronomy School of Physics Peking University Beijing100871 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China Polar Research Institute of China 451 Jinqiao Road Shanghai200136 China Center for Astronomical Mega-science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China UKIRT Observatory HiloHI96720 United States University of the Chinese Academy of Sciences Beijing100049 China Department of Physics Pennsylvania State University University ParkPA16802 United States Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China

Very few low-ionization broad absorption line (LoBAL) QSOs have been found at high redshifts to date. One high-redshift LoBAL QSO, J0122+1216, was recently discovered at the Lijiang 2.4-m Telescope with an initial redshift determination of 4.76. Aiming to investigate its physical properties, we carried out follow-up observations in the optical and near-IR spectroscopy. Near-IR spectra from UKIRT and P200 confirms that it is a LoBAL, with a new redshift determination of 4.82 ± 0.01 based on the Mg ii emission-line. The new Mg ii redshift determination reveals strong blueshifts and asymmetry of the high-ionization emission lines. We estimated a black hole mass of ∼ 2.3×109M☉ and Eddington ratio of ∼ 1.0 according to the empirical Mg ii-based single-epoch relation and bolometric correction factor. It is possible that strong outflows are the result of an extreme quasar environment driven by the high Eddington ratio. A lower limit on the outflowing kinetic power (> 0.9%LEdd) was derived from both emission and absorption lines, indicating these outflows play a significant role in the feedback process to regulate the growth of its black hole as well as host galaxy evolution. Copyright © 2017, The Authors. All rights reserved.

关键词： Ionization

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On properties of mass transfer in an Algol-type binary system:an example of VV Vir

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Research in Astronomy and Astrophysics 2014年第2期14卷 179-192页

作者： Jia Zhang Sheng-Bang Qian Lin-Qiao Jiang 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

Some properties of mass transfer within a semi-detached binary system are discussed based on an example of VV Vir. The observations and analysis of VV Vir show that it is a semi-detached binary system with the less massive cooler component filling its Roche lobe, which is also called an Algol-type binary system. Based on the parameters of this semi-detached binary, a theoretical study on the mass flow is carded out, including the trajectory of the mass flow, the position, radius and temperature of the impact spot caused by the mass flow, the inconsistent form of the mass flow and the possibly huge rate of energy transfer carried by the mass flow. Humps and distortions in light curves of VV Vir are deemed to be weak evidence for the theoretical results.

关键词： binaries eclipsing -- stars individual （VV Vir） -- techniques photo-metric

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Observations of SN 2017ein reveal shock breakout emission and a massive progenitor star for a type Ic supernova

arXiv

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arXiv 2018年

作者： Xiang, Danfeng Wang, Xiaofeng Mo, Jun Wang, Lingjun Smartt, Stephen Fraser, Morgan Ehgamberdiev, Shuhrat A. Mirzaqulov, Davron Zhang, Jujia Zhang, Tianmeng Vinko, Jozsef Wheeler, J. Craig Hosseinzadeh, Griffin Howell, D. Andrew McCully, Curtis DerKacy, James M. Baron, E. Brown, Peter Zhang, Xianfei Bi, Shaolan Song, Hao Zhang, Kaicheng Rest, A. Nomoto, Kenichi Tolstov, Alexey Blinnikov, Sergei Tsinghua University Beijing100084 China Astroparticle Physics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China Astrophysics Research Centre School of Mathematics and Physics Queens University Belfast BelfastBT7 1NN United Kingdom School of Physics University College Dublin Belfield Dublin 4 Ireland Ulugh Beg Astronomical Institute Uzbekistan Academy of Sciences Uzbekistan Tashkent100052 Uzbekistan Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China National Astronomical Observatory of China Chinese Academy of Sciences Beijing100012 China Konkoly Observatory MTA CSFK Konkoly Thege M. ut 15-17 Budapest1121 Hungary Department of Optics & Quantum Electronics University of Szeged Dom ter 9 Szeged6720 Hungary Department of Astronomy University of Texas at Austin AustinTX78712 United States Las Cumbres Observatory 6740 Cortona Drive Suite 102 GoletaCA93117-5575 United States Department of Physics University of California Santa BarbaraCA93106-9530 United States Homer L. Dodge Department of Physics and Astronomy University of Oklahoma NormanOK United States George P. and CynthiaWoods Mitchell Institute for Fundamental Physics & Astronomy Texas A. & M. University Department of Physics and Astronomy 4242 TAMU College StationTX77843 United States Department of Astronomy Beijing Normal University Beijing100875 China Space Telescope Science Institute 3700 San Martin Drive BaltimoreMD21218 United States Department of Physics and Astronomy Johns Hopkins University BaltimoreMD21218 United States University of Tokyo Institutes for Advanced Study University of Tokyo 5-1-5 Kashiwanoha Kashiwa Chiba277-8583 Japan Moscow117218 Russia Moscow127055 Rus

We present optical and ultraviolet observations of nearby type Ic supernova SN 2017ein as well as detailed analysis of its progenitor properties from both the early-time observations and the prediscovery Hubble Space Telescope (HST) images. The optical light curves started from within one day to ∼275 days after explosion, and optical spectra range from ∼2 days to ∼90 days after explosion. Compared to other normal SNe Ic like SN 2007gr and SN 2013ge, SN 2017ein seems to have more prominent CII absorption and higher expansion velocities in early phases, suggestive of relatively lower ejecta mass. The earliest photometry obtained for SN 2017ein show indications of shock cooling. The best-fit obtained by including a shock cooling component gives an estimate of the envelope mass as ∼0.02 M☉ and stellar radius as 8±4 R☉. Examining the pre-explosion images taken with the HST WFPC2, we find that the SN position coincides with a luminous and blue point-like source, with an extinction-corrected absolute magnitude of MV ∼−8.2 mag and MI∼−7.7 mag. Comparisons of the observations to the theoretical models indicate that the counterpart source was either a single WR star or a binary with whose members had high initial masses, or a young compact star cluster. To further distinguish between different scenarios requires revisiting the site of the progenitor with HST after the SN fades away. Copyright © 2018, The Authors. All rights reserved.

关键词： Supernovae

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Photometric investigation of the K-type extremely shallow contact binary V1799 Orion

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Research in Astronomy and Astrophysics 2014年第9期14卷 1157-1165页

作者： Nian-Ping Liu Sheng-Bang Qian Wen-Ping Liao Jia-Jia He Er-Gang Zhao Liang Liu Yunnan Observatories Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences University of Chinese Academy of Sciences

New multi-color light curves of the very short period K-type eclipsing binary V1799 Ori were obtained and analyzed with the Wilson-Devinney code. The photometric solutions reveal that the system is a W-type shallow-contact binary with a mass ratio of q = 1.335（4-0.005） and a degree of contact of about f = 3.5（-4-1.1）%. In general, the results are in good agreement with what is reported by Samec. Dramatic manifestations of the O＇Connell effect that appear in the light curves can be explained well by employing starspots on the binary surface, which confirms that the system is active at present. Several new times of light minimum were obtained. All the avail- able times of light minimum were collected, along with the recalculated and newly obtained values. Applying a least-squares method to the constructed O - C diagram, a new ephemeris is derived for V1799 Ori. The orbital period is found to show a continuous weak increase at a rate of 1.8（±0.6） × 10^-8 d yr^-1. The extremely shallow contact, together with the period increase, suggests that the binary may be at a critical stage predicted by thermal relaxation oscillation theory.

关键词： binaries： close -- binaries： eclipsing -- stars： individual （V1799 Off）

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The influences of convective overshooting and semiconvection on the chemical evolution of massive stars

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Research in Astronomy and Astrophysics 2014年第8期14卷 979-991页

作者： Cai-Yun Ding Yan Li Yunnan Observatories Chinese Academy of Sciences Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences University of Chinese Academy of Sciences

In massive stars, convection in the interior is different from that of inter- mediate and small mass stars. In the main-sequence phase of small mass stars, there is a convective core and a radiative envelope, between which are the radiative inter- mediate layers with uneven chemical abundances. Semiconvection would occur in the intermediate layers between the convective core and the homogeneous envelope in massive stars. We treat core convective overshooting and semiconvection together as a process. We found that when decreasing overshooting, the semiconvection is more pronounced. In these two processes, we introduce one diffusive parameter D, which is different from other authors who have introduced different parameters for these two zones. The influences of the turbulent diffusion process on chemical evolution and other quantities of the stellar structure are shown in the present paper.

关键词： stars evolution -- stars abundances -- convection -- diffusion

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