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SN 2017fgc: A fast-expanding Type Ia supernova exploded in massive shell galaxy NGC 474

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arXiv 2021年

作者： Zeng, Xiangyun Wang, Xiaofeng Esamdin, Ali Pellegrino, Craig Burke, Jamison Stahl, Benjamin E. Zheng, Weikang Filippenko, Alexei V. Howell, D. Andrew Sand, D.J. Valenti, Stefano Mo, Jun Xi, Gaobo Liu, Jialian Zhang, Jujia Li, Wenxiong Iskandar, Abdusamatjan Zhang, Mengfan Lin, Han Sai, Hanna Xiang, Danfeng Wei, Peng Zhang, Tianmeng Reichart, D.E. Brink, Thomas G. McCully, Curtis Hiramatsu, Daichi Hosseinzadeh, Griffin Jeffers, Benjamin T. Ross, Timothy W. Stegman, Samantha Wang, Lifan Zhang, Jicheng Ma, Shuo Xinjiang Astronomical Observatory Chinese Academy of Sciences Xinjiang Urumqi830011 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China Tsinghua University Beijing100084 China Beijing Planetarium Beijing Academy of Science of Technology Beijing100044 China Department of Physics University of California Santa BarbaraCA93106-9530 United States Las Cumbres Observatory 6740 Cortona Drive GoletaCA93117-5575 United States Department of Astronomy University of California BerkeleyCA94720-3411 United States Department of Physics University of California BerkeleyCA94720-7300 United States Marc J. Staley Graduate Fellow Miller Senior Fellow Miller Institute for Basic Research in Science University of California BerkeleyCA94720 United States Steward Observatory University of Arizona 933 North Cherry Avenue TucsonAZ85721-0065 United States Department of Physics University of California DavisCA95616 United States 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 The School of Physics and Astronomy Tel Aviv University Tel Aviv69978 Israel Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing100012 China Department of Physics and Astronomy University of North Carolina at Chapel Hill Chapel HillNC27599 United States Center for Astrophysics Harvard and Smithsonian 60 Garden Street CambridgeMA02138-1516 United States Las CumbresObservatory 6740 Cortona Drive GoletaCA9311-5575 United States Department of Chemistry University of Wisconsin MadisonWI53706 United States George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy Texas AandM University Department of Physics and A

We present extensive optical photometric and spectroscopic observations of the high-velocity (HV) Type Ia supernova (SN Ia) 2017fgc, covering the phase from ∼12 d before to ∼ 389 d after maximum brightness. SN 2017fgc is similar to normal SNe Ia, with an absolute peak magnitude of MB max ≈ -19:32 ± 0:13 mag and a post-peak decline of Δm15(B) = 1:05 ± 0:07 mag. Its peak bolometric luminosity is derived as (1:32 ± 0:13) × 1043erg s-1, corresponding to a 56Ni mass of 0:51 ± 0:03Mo. The light curves of SN 2017fgc are found to exhibit excess emission in the UBV bands in the early nebular phase and pronounced secondary shoulder/maximum features in the RrIi bands. Its spectral evolution is similar to that of HV SNe Ia, with a maximum-light Si II velocity of 15;000 ± 150 km s-1and a post-peak velocity gradient of ∼ 120 ± 10 km s-1d-1. The Fe II and Mg II lines blended near 4300 Å and the Fe II, Si II, and Fe III lines blended near 4800 Åare obviously stronger than those of normal SNe Ia. Inspecting a large sample reveals that the strength of the two blends in the spectra, and the secondary peak in the i=r-band light curves, are found to be positively correlated with the maximum-light Si II velocity. Such correlations indicate that HV SNe Ia may experience more complete burning in the ejecta and/or that their progenitors have higher metallicity. Examining the birthplace environment of SN 2017fgc suggests that it likely arose from a stellar environment with young and high-metallicity populations. © 2021, CC BY.

关键词： Supernovae

The birthrates of SNe Ia in globular clusters

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Proceedings of the International Astronomical Union 2017年第S316期12卷 343-344页

作者： Bo Wang Dongdong Liu Yunnan Observatories Chinese Academy of Sciences Kunming 650216 China (email: wangbo@***) Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650216 China

Globular clusters has been proposed as testbeds for type Ia supernovae (SNe Ia). In this work, using a detailed binary population synthesis approach, we studied the birthrates of SNe Ia from various progenitor models in globular clusters, including the single-degenerate model, the double-degenerate model and the Sub-Chandrasekhar model. Here, a single starburst with a total mass of 106M⊙ is assumed.

关键词： binaries: close supernovae: general white dwarfs

Determining the core radio luminosity function of radio agns via copula

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arXiv 2018年

作者： Yuan, Zunli Wang, Jiancheng Worrall, D.M. Zhang, Bin-Bin Mao, Jirong 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 Beijing100012 China HH Wills Physics Laboratory University of Bristol Tyndall Avenue BristolBS8 1TL United Kingdom School of Astronomy and Space Science Nanjing University Nanjing210093 China Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Ministry of Education China

The radio luminosity functions (RLFs) of active galactic nuclei (AGNs) are traditionally measured based on total emission, which doesn't reflect the current activity of the central black hole. The increasing interest in compact radio cores of AGNs requires determination of the RLF based on core emission (i.e., core RLF). In this work we have established a large sample (totaling 1207) of radio-loud AGNs, mainly consisting of radio galaxies (RGs) and steep-spectrum radio quasars (SSRQs). Based on the sample, we explore the relationship between core luminosity (Lc) and total luminosity (Lt) via a powerful statistical tool called "Copula". The conditional probability distribution p(log Lc | log Lt) is obtained. We derive the core RLF as a convolution of p(log Lc | log Lt) with the total RLF which was determined by previous work. We relate the separate RG and SSRQ core RLFs via a relativistic beaming model and find that SSRQs have an average Lorentz factor of γ = 9.84+3−2..6150, and that most are seen within 8◦ . θ . 45◦ of the jet axis. Compared with the total RLF which is mainly contributed by extended emission, the core RLF shows a very weak luminosity-dependent evolution, with the number density peaking around z ∼ 0.8 for all luminosities. Differences between core and total RLFs can be explained in a framework involving a combination of density and luminosity evolutions where the cores have significantly weaker luminosity evolution than the extended emission. Copyright © 2018, The Authors. All rights reserved.

关键词： Luminance

Erratum: 'The Escape of the Hydrogen-rich Atmosphere of Exoplanets: Mass-loss Rates and the Absorptions of Stellar Lyα' (2019, ApJ, 880, 90)

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The Astrophysical Journal 2019年第2期883卷

作者： Dongdong Yan Jianheng Guo Yunnan Observatories Chinese Academy of Sciences P.O. Box 110 Kunming 650011 People's Republic of China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing People's Republic of China Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming 650011 People's Republic of China

Alma imaging of the CO (7−6) line emission in the submillimeter galaxy less 073 at redshift 4.755

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arXiv 2020年

作者： Zhao, Yinghe Lu, Nanyao Díaz-Santos, Tanio Gao, Yu Xu, C. Kevin Charmandaris, Vassilis Inami, Hanae Rigopoulou, Dimitra Sanders, David B. Huang, Jiasheng Wang, Zhong Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China Center for Astronomical Mega-Science CAS 20A Datun Road Chaoyang District Beijing100012 China National Astronomical Observatories of China Chinese Academy of Sciences Beijing100012 China China-Chile Joint Center for Astronomy Chinese Academy of Sciences Camino El Observatorio 1515 Las Condes Santiago Chile Núcleo de Astronomía de la Facultad de Ingeniería Universidad Diego Portales Av. Ejército Libertador 441 Santiago Chile Department of Astronomy Xiamen University XiamenFujian361005 China Department of Physics University of Crete HeraklionGR-71003 Greece IAASARS National Observatory of Athens PenteliGR-15236 Greece Hiroshima Astrophysical Science Center Hiroshima University 1-3-1 Kagamiyama Higashi-HiroshimaHiroshima739-8526 Japan Department of Physics University of Oxford Keble Road OxfordOX1 3RH United Kingdom University of Hawaii Institute for Astronomy 2680 Wood-lawn Drive HonoluluHI96822 United States

In this paper we present our imaging observations on the CO (7−6) line and its underlying continuum emission of the young submillimeter galaxy LESS 073 at redshift 4.755, using the Atacama Large Millimeter/submillimeter Array (ALMA). At the achieved resolution of ∼1′′.2 × 0′′.9 (8 × 6 kpc2), the CO (7−6) emission is largely unresolved (with a deconvolved size of 1′′.1(±0′′.5) × 0′′.9(±0′′.8).), and the continuum emission is totally unresolved. The CO (7−6) line emission has an integrated flux of 0.86 ± 0.08 Jy km s−1, and a line width of 343 ± 40 km s−1. The continuum emission has a flux density of 0.51 mJy. By fitting the observed far-infrared (FIR) spectral energy distribution of LESS 073 with a single-temperature modified blackbody function, we obtained a dust temperature Tdust = 57.6 ± 3.5 K, 60-to-100 µm flux density ratio f60/f100 = 0.86 ± 0.08, and total infrared luminosity LIR = (5.8 ± 0.9) × 1012 L☉. The SED-fit-based f60/f100 is consistent with those estimated from various line ratios as advocated by our earlier work, indicating that those proposed line-ratio-based method can be used to practically derive f60/f100 for high-z sources. The total molecular gas mass of LESS 073 is (3.3 ± 1.7) × 1010 M☉, and the inferred gas depletion time is about 43 Myr. Copyright © 2020, The Authors. All rights reserved.

关键词： Galaxies

Evolving ONe WD+He star systems to intermediate-mass binary pulsars

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arXiv 2018年

作者： Liu, D. Wang, B. Chen, W. Zuo, Z. Han, Z. Key Laboratory for Structure and Evolution of Celestial Objects Yunnan Observatories Chinese Academy of Sciences Kunming 650216 China University of Chinese Academy of Sciences Beijing100049 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing100012 China School of Physics and Electrical Information Shangqiu Normal University Shangqiu476000 China School of Science Xi'an Jiaotong University Xi'an710049 China

It has been suggested that accretion-induced collapse (AIC) is a non-negligible path for the formation of the observed neutron stars (NSs). An ONe white dwarf (WD) that accretes material from a He star may experience AIC process and eventually produce intermediate-mass binary pulsars (IMBPs), named as the ONe WD+He star scenario. Note that previous studies can only account for part of the observed IMBPs with short orbital periods. In this work, we investigate the evolution of about 900 ONe WD+He star binaries to explore the distribution of IMBPs. We found that the ONe WD+He star scenario could form IMBPs including pulsars with 5-340ms spin periods and 0.75-1.38Mo WD companions, in which the orbital periods range from 0.04 to 900 d. Compared with the 20 observed IMBPs, this scenario can cover the parameters of 13 sources in the final orbital period-WD mass plane and the Corbet diagram, most of which has short orbital periods. We found that the ONe WD+He star scenario can explain almost all the observed IMBPs with short orbital periods. This work can well match the observed parameters of PSR J1802-2124 (one of the two precisely observed IMBPs), providing a possible evolutional path for its *** also speculate that the compact companion of HD 49798 (a hydrogen depleted sdO6 star) may be not a NS based on the present work. Copyright © 2018, The Authors. All rights reserved.

关键词： White dwarfs

Optical and γ-ray variability behaviors of 3C 454.3 from 2006 to 2011

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arXiv 2018年

作者： Fan, Xu-Liang Li, Shao-Kun Liao, Neng-Hui Chen, Liang Liu, Hong-Tao Lu, Kai-Xing Yan, Da-Hai Zhang, Rui-Yu Guo, Qian Wu, Qingwen Bai, Jin-Ming School of Physics Huazhong University of Science and Technology Wuhan430074 China Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory Chinese Academy of Sciences Nanjing210008 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences 80 Nandan Road Shanghai200030 China University of Chinese Academy of Sciences Beijing100049 China

We present our photometric monitoring of a flat spectrum radio quasar (FSRQ) 3C 454.3 at Yunnan observatories from 2006 to 2011. We find that the optical color of 3C 454.3 shows obvious redder-when-brighter trend, which reaches a saturation stage when the source is brighter than 15.15 mag at V band. We perform a simulation with multiple values of disk luminosity and spectral index to reproduce the magnitude-color diagram. The results show that the contamination caused by the disk radiation alone is difficult to produce the observed color variability. The variability properties during the outburst in December 2009 are also compared with γ-ray data derived from Fermi γ-ray space telescope. The flux variation of these two bands follow a linear relation with Fγ∝ FR1.14±0.07, which provides an observational evidence for external Compton process in 3C 454.3. Meanwhile, this flux correlation indicates that electron injection is the main mechanism for variability origin. We also explore the variation of the flux ratio Fγ/FRand the detailed structures in the lightcurves, and discuss some possible origins for the detailed variability behaviors. Copyright © 2018, The Authors. All rights reserved.

关键词： Galaxies

Which evolutionary status does the Blue Large-Amplitude Pulsators stay at?

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arXiv 2018年

作者： Wu, Tao Li, Yan 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 Kunming Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China University of Chinese Academy of Sciences Beijing100049 China

Asteroseismology is a very useful tool for exploring the stellar interiors and evolution- ary status and for determining stellar fundamental parameters, such as stellar mass, radius, surface gravity, and the stellar mean density. In the present work, we use it to preliminarily analyze the 14 new-type pulsating stars: Blue Large-Amplitude Pulsators (BLAPs) which is observed by OGLE project, to roughly analyze their evolutionary status. We adopt the theory of single star evolution and artificially set the mass loss rate of M = -2 × 10-4Mo/year and mass loss beginning at the radius of R = 40 Ro on red giant branch to generate a series of theoretical models. Based on these theoretical models and the corresponding observations, we find that those BLAP stars are more likely to be the core helium burning stars. Most of them are in the middle and late phase of the helium burning. Copyright © 2018, The Authors. All rights reserved.

关键词： Gravitation

Vertical structure of radiation-pressure-dominated thin disks: Link between vertical advection and convective stability

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arXiv 2017年

作者： Gong, Hong-Yu Gu, Wei-Min Department of Astronomy Xiamen University Xiamen Fujian361005 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China

In the classic picture of standard thin accretion disks, the viscous heating is balanced by the radiative cooling through the diffusion process, and the radiation-pressure-dominated inner disk suffers convec-tive instability. However, recent simulations have shown that the vertical advection process owing to the magnetic buoyancy can make significant contribution to the energy transport. In addition, no convective instability has been found by comparing the simulation results with the local convective stability criterion. In this work, following the spirit of simulations, we revisit the vertical structure of radiation-pressure-dominated thin disks by including the vertical advection process. Our study indicates a link between the additional energy transport and the convectively stable property. Thus, the vertical advection not only has significant contribution to the energy transport, but also plays an important role to make the disk convectively stable. Our analyses may be helpful to understand the discrepancy between the classic theory and simulations on standard thin disks. Copyright © 2017, The Authors. All rights reserved.

关键词： Stability criteria