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arXiv 2019年

作者： Timlin, John D. Brandt, W.N. Ni, Q. Luo, B. Pu, Xingting Schneider, D.P. Vivek, M. Yi, W. Department of Astronomy & Astrophysics Pennsylvania State University 525 Davey Lab University ParkPA16802 United States Institute for Gravitation and the Cosmos Pennsylvania State University University ParkPA16802 United States Department of Physics Pennsylvania State University 104 Davey Lab University ParkPA16802 United States School of Astronomy and Space Science Nanjing University Nanjing Jiangsu210093 China Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Ministry of Education Nanjing Jiangsu210093 China College of Science Nanjing Forestry University Nanjing Jiangsu210037 China Yunnan Observatories Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China

We present Chandra observations of 2106 radio-quiet quasars in the redshift range 1.7 ≤ z ≤ 2.7 from the Sloan Digital Sky Survey (SDSS), through data release fourteen (DR14), that do not contain broad absorption lines (BAL) in their rest-frame UV spectra. This sample adds over a decade worth of SDSS and Chandra observations to our previously published sample of 139 quasars from SDSS DR5 which is still used to correlate X-ray and optical/UV emission in typical quasars. We fit the SDSS spectra for 753 of the quasars in our sample that have high-quality (exposure time ≥ 10 ks and off-axis observation angle ≤ 100) X-ray observations, and analyze their X-ray-to-optical SED properties (αox and ∆αox) with respect to the measured CIV and MgII emission-line rest-frame equivalent width (EW) and the CIV emission-line blueshift. We find significant correlations (at the ≥ 99.99% level) between αox and these emission-line parameters, as well as between ∆αox and C iv EW. Slight correlations are found between ∆αox and C iv blueshift, Mg ii EW, and the C iv EW to Mg ii EW ratio. The best-fit trend in each parameter space is used to compare the X-ray weakness (∆αox) and optical/UV emission properties of typical quasars and weak-line quasars (WLQs). The WLQs typically exhibit weaker X-ray emission than predicted by the typical quasar relationships. The best-fit relationships for our typical quasars are consistent with predictions from the disk-wind quasar model. The behavior of the WLQs compared to our typical quasars can be explained by an X-ray "shielding" model. Copyright © 2019, The Authors. All rights reserved.

关键词： Galaxies

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Spectroscopy of broad absorption line quasars at 3 Z 5-I: Evidence for quasar winds shaping broad/narrow emission line regions

arXiv

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arXiv 2019年

作者： Yi, Weimin Zuo, Wenwen Yang, Jinyi Wang, Feige Timlin, John Grier, Catherine Wu, Xue-Bing Fan4, Xiaohui Bai, Jin-Ming Yunnan Observatories Kunming650216 China Department of Astronomy and Astrophysics Pennsylva-Nia State University 525 Davey Lab PA16802 United States Shanghai Astronomical Observatory Shanghai200030 China University of Arizona Steward Observatory 933 North Cherry Avenue TucsonAZ85721-0065 United States Kavli Institute for Astronomy and Astrophysics Peking Uni-versity Beijing100871 China Department of Astronomy Peking University Yi He Yuan Lu 5 Hai Dian District Beijing100871 China Cas Key Laboratory for Research in Galaxies and Cosmol-Ogy Department of Astronomy University of Science and Tech-Nology of China China Key Laboratory for Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China

We present an observational study of 22 broad absorption line quasars (BAL QSOs) at 3 z 5 based on optical/near-IR spectroscopy, aiming to investigate quasar winds and their effects. The near-IR spectroscopy covers the Hβ and/or Mg ii broad emission lines (BELs) for these quasars, allowing us to estimate their central black hole (BH) masses in a robust way. We found that our BAL QSOs on average do not have a higher Eddington ratio than that from non-BAL QSOs matched in redshift and/or luminosity. In a subset consisting of seven strong BAL QSOs possessing subrelativistic BAL outflows, we see the prevalence of large C iv-BEL blueshift (∼3100 km s-1) and weak [O iii] emission (particularly the narrow [O iii]λ5007 component), indicative of nuclear outflows affecting the narrow emission-line (NEL) regions. In another subset consisting of thirteen BAL QSOs having simultaneous observations of Mg ii and Hβ, we found a strong correlation between 3000 °A and 5000 °A monochromatic luminosity, consistent with that from non-BAL QSOs matched in redshift and luminosity;however, there is no correlation between Mg ii and Hβ in FWHM, likely due to nuclear outflows influencing the BEL regions. Our spectroscopic investigations offer strong evidence that the presence of nuclear outflows plays an important role in shaping the BEL/NEL regions of these quasars and possibly, regulating the growth of central supermassive black holes (SMBHs). We propose that BEL blueshift and BAL could be different manifestations of the same outflow system viewed at different sightlines and/or phases. Copyright © 2019, The Authors. All rights reserved.

关键词： Electromagnetic wave emission

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Synchrotron polarization radiative transfer: Relativistic thermal electrons contribution

arXiv

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arXiv 2018年

作者： Mao, Jirong Covino, Stefano Wang, Jiancheng Yunnan Observatories Chinese Academy of Sciences Kunming Yunnan Province650011 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China I-23807 Italy

Relativistic thermal electrons moving in a large-scale magnetic field can produce synchrotron radiation. Linear synchrotron polarization can also be produced by the relativistic thermal electrons. In this paper, we utilize a hybrid thermalnonthermal electron energy distribution to calculate circular synchrotron polarization. We further compute the radiative transfer of the synchrotron polarization in the optical and radio bands when we consider the contribution of the thermal electrons. We attempt to apply the polarization results to some astrophysical objects, such as kilonova like AT 2017gfo/GW170817, the fast radio burst (FRB), the Gamma-ray burst (GRB) afterglow, and the supernova remnant (SNR). The large optical depth of radiative transfer eαects the small polarization degrees of these populations when the media surrounding the synchrotron sources take heavy absorption to the polarized photons. We need a strong magnetic field in our model to reproduce the linear and circular polarization properties that were observed in FRB 140514. This indicates that FRBs have a neutron star origin. Copyright © 2018, The Authors. All rights reserved.

关键词： Polarization

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DISCOVERY AND TIMING OF MILLISECOND PULSARS IN THE GLOBULAR CLUSTER M5 (NGC 5904) WITH FAST AND ARECIBO

arXiv

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arXiv 2023年

作者： Zhang, Lei Freire, Paulo C.C. Ridolfi, Alessandro Pan, Zhichen Zhao, Jiaqi Heinke, Craig O. Chen, Jianxing Cadelano, Mario Pallanca, Cristina Hou, Xian Fu, Xiaoting Dai, Shi Gügercinoglu, Erbil Guo, Meng Hessels, Jason Hu, Jiale Li, Guodong Ni, Mengmeng Pan, Jingshan Ransom, Scott M. Ruan, Qitong Stairs, Ingrid Tsai, Chao-Wei Wang, Pei Wang, Long Wang, Na Wu, Qingdong Yuan, Jianping Zhang, Jie Zhu, Weiwei Zhang, Yongkun Li, Di National Astronomical Observatories Chinese Academy of Sciences A20 Datun Road Chaoyang District Beijing100101 China Centre for Astrophysics and Supercomputing Swinburne University of Technology P.O. Box 218 HawthornVIC3122 Australia Max-Planck-Institut für Radioastronomie Auf dem Hügel 69 Bonn53121 Germany INAF - Osservatorio Astronomico di Cagliari Via della Scienza 5 CA SelargiusI-09047 Italy Guizhou Radio Astronomical Observatory Guizhou University Guiyang550025 China College of Astronomy and Space Sciences University of Chinese Academy of Sciences Chinese Academy of Sciences Beijing100101 China Key Laboratory of Radio Astronomy and Technology Chinese Academy of Sciences Beijing100101 China Department of Physics University of Alberta CCIS 4-183 EdmontonABT6G 2E1 Canada Dipartimento di Fisica e Astronomia "Augusto Righi" Alma Mater Studiorum Università di Bologna via Piero Gobetti 93/2 BolognaI-40129 Italy INAF-Osservatorio di Astrofisica e Scienze dello Spazio di Bologna Via Piero Gobetti 93/3 BolognaI-40129 Italy 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 Purple Mountain Observatory Chinese Academy of Sciences Nanjing210023 China School of Science Western Sydney University Locked Bag 1797 PenrithNSW2751 Australia National Supercomputing Center in Jinan Qilu University of Technology 28666 East Jingshi Road Licheng District Jinan250103 China Jinan Institute of Supercomputing Technology 28666 East Jingshi Road Licheng District Jinan250103 China ASTRON The Netherlands Institute for Radio Astronomy Oude Hoogeveensedijk 4 Dwingeloo7991 PD Netherlands Anton Pannekoek Institute for Astronomy University o

We report on a comprehensive multi-wavelength study of the pulsars in the globular cluster (GC) M5, including the discovery of M5G, a new compact non-eclipsing "black widow" pulsar. Thanks to the analysis of 34 years of radio data taken with the FAST and Arecibo telescopes, we obtained new phase-connected timing solutions for four pulsars and improved those of the other three. These have resulted in, among other things: a) much improved proper motions for five pulsars, with transverse velocities (relative to the cluster) that are smaller than their respective escape velocities;b) 3-σ and 1.5-σ detections of Shapiro delays in M5F and M5D, respectively;c) greatly improved measurement of the periastron advance in M5B, whose value of ω = 0.01361(6)◦ implies that M5B is still likely to be a heavy (Equation presented) neutron star. The binary pulsars M5D, E and F are confirmed to be in low-eccentricity binary systems, the low-mass companions of which are newly identified to be He white dwarfs using Hubble Space Telescope data. Four pulsars are also found to be associated with X-ray sources. Similarly to the eclipsing pulsar M5C, M5G shows little or no non-thermal X-ray emission, indicative of weak synchrotron radiation produced by intra-binary shocks. All the seven pulsars known in M5 have short spin periods ( Copyright © 2023, The Authors. All rights reserved.

关键词： Pulsars

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Erratum: Variations of the mixing character of dipolar mixed modes in red giant stars

引用

Monthly Notices of the Royal Astronomical Society 2020年第1期497卷 167-172页

作者： C Jiang M Cunha J Christensen-Dalsgaard Q S Zhang School of Physics and Astronomy Sun Yat-Sen University No. 135 Xingang Xi Road Guangzhou 510275 P. R. China Instituto de Astrofísica e Ciências do Espaço Universidade do Porto CAUP Rua das Estrelas PT-4150-762 Porto Portugal jiangch53@*** Instituto de Astrofísica e Ciências do Espaço Universidade do Porto CAUP Rua das Estrelas PT-4150-762 Porto Portugal School of Physics and Astronomy University of Birmingham Birmingham B15 2TT United Kingdom Stellar Astrophysics Centre Department of Physics and Astronomy Aarhus University Ny Munkegade 120 DK-8000 Aarhus C Denmark Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming 650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing 100012 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming 650216 China University of Chinese Academy of Sciences Beijing 100049 China

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Supermassive black holes with high accretion rates in active galactic nuclei: X. Optical variability characteristics

arXiv

引用

arXiv 2019年

作者： Lu, Kai-Xing Huang, Ying-Ke Zhang, Zhi-Xiang Wang, Kai Du, Pu Hu, Chen Xiao, Ming Li, Yan-Rong Bai, Jin-Ming Bian, Wei-Hao Yuan, Ye-Fei Ho, Luis C. Wang, Jian-Min Yunnan Observatories Chinese Academy of Sciences Kunming Yunnan650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences 19B Yuquan Road Beijing100049 China Physics Department Nanjing Normal University Nanjing210097 China Department of Astronomy University of Science and Technology of China Hefei230026 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China Department of Astronomy School of Physics Peking University Beijing100871 China National Astronomical Observatories of China Chinese Academy of Sciences 20A Datun Road Beijing100020 China

We compiled a sample of 73 active galactic nuclei (AGNs) with reverberation mapping (RM) observations from RM campaigns including our ongoing campaign of monitoring super-Eddington accreting massive black holes (SEAMBHs). This sample covers a large range of black hole (BH) mass (M•= 10,6-9Mo), dimensionless accretion rates (M = 10-2.7- 102.7) and 5100 Å luminosity (L5100= 1042-46erg s-1), allowing us to systematically study the AGN variability and their relations with BH mass, accretion rates, and optical luminosity. We employed the damped random walk (DRW) model to delineate the optical variability of continuum at 5100 Å and obtained damped variability timescale (τd) and amplitude (σd) using a Markov Chain Monte Carlo (MCMC) method. We also estimated the traditional variability amplitudes (Fvar), which provide a model-independent measure and therefore are used to test the DRW results. We found that AGN variability characteristics are generally correlated with (M•,M,L5100). These correlations are smooth from sub-Eddington to super-Eddington accretion AGNs, probably implying that the AGN variability may be caused by the same physical mechanism. Copyright © 2019, The Authors. All rights reserved.

关键词： Luminance

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Formation of the electronic spectrum in relativistic jets of gamma-ray blazars

arXiv

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arXiv 2018年

作者： Zheng, Y.G. Long, G.B. Yang, C.Y. Bai, J.M. Department of Physics Yunnan Normal University Kunming650092 China Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Shandong University Weihai264209 Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for Structure and Evolution of Celestial Objects Chinese Academy of Sciences Department of Physics and Astronomy Sun Yat-Sen University Zhuhai519082 China

We describe the theory of Fermi-type acceleration, including first-order Fermi acceleration at a parallel shock front and second-order Fermi acceleration in a test particle limit. Including the theory of the turbulent acceleration and the derivation of the general Fokker-Planck equation, we take into account the basic particle-transport equation and the Fokker-Planck equation with spatially homogeneous isotropic distribution. In the cases of some special physical processes, we construct the particle-transport equations, and compile the analytical or semianalytical solutions in 11 different cases. Even though, traditionally, one of the electron energy distributions for these different cases can be used to reproduce the multi-wavelength emission of a blazar, due to very long integration times of high-energy observations, a time-integrated electron energy distribution should be introduced in approaches to modeling the multi-wavelength spectral energy distribution of blazars, especially in modeling the flaring state. Copyright © 2018, The Authors. All rights reserved.

关键词： Gamma rays

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SOLAR MODELS WITH CONVECTIVE OVERSHOOT, THE SOLAR-WIND MASS LOSS, AND A PMS DISK ACCRETION: HELIOSEISMIC QUANTITIES, LI DEPLETION AND NEUTRINO FLUXES

arXiv

引用

arXiv 2019年

作者： Zhang, Qian-Sheng Li, Yan Christensen-Dalsgaard, Jørgen Yunnan Observatories 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 the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China Stellar Astrophysics Centre Department of Physics and Astronomy Aarhus University Aarhus CDK-8000 Denmark Kavli Institute for Theoretical Physics University of California Santa Barbara CA93106-4030 United States

Helioseismic observations have revealed many properties of the Sun: the depth and the helium abundance of the convection zone, the sound-speed and the density profiles in the solar interior. Those constraints have been used to judge the stellar evolution theory. With the old solar composition (e.g., GS98), the solar standard model is in reasonable agreement with the helioseismic constraints. However, a solar model with revised composition (e.g., AGSS09) with low abundance Z of heavy elements cannot be consistent with those constraints. This is the so-called "solar abundance problem", standing for more than ten years even with the recent upward revised Ne abundance. Many mechanisms have been proposed to mitigate the problem. However, there is still not a low-Z solar model satisfying all helioseismic constraints. In this paper, we report a possible solution to the solar abundance problem. With some extra physical processes that are not included in the standard model, solar models can be significantly improved. Our new solar models with convective overshoot, the solar wind, and an early mass accretion show consistency with helioseismic constraints, the solar Li abundance, and observations of solar neutrino fluxes. Copyright © 2019, The Authors. All rights reserved.

关键词： Solar wind

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SDSS J094635.06+101706.1: A redshift one, very radio-loud, γ-ray emitting narrow-line Seyfert 1 galaxy

arXiv

引用

arXiv 2019年

作者： Yao, Su Komossa, S. Liu, Wen-Juan Yi, Weimin Yuan, Weimin Zhou, Hongyan Wu, Xue-Bing Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China National Astronomical Observatories Chinese Academy of Sciences Beijing100012 China Max-Planck Institut für Radioastronomie Auf dem Hügel 69 Bonn53121 Germany Yunnan Observatories Chinese Academy of Sciences Kunming Yunnan650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China Department of Astronomy & Astrophysics Pennsylvania State University 525 Davey Lab University ParkPA16802 United States Key Laboratory of Space Astronomy and Technology National Astronomical Observatories Chinese Academy of Sciences Beijing100012 China CAS Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy USTC Hefei Anhui230026 China SOA Key Laboratory for Polar Science Polar Research Institute of China 451 Jinqiao Road Shanghai200136 China Department of Astronomy School of Physics Peking University Beijing100871 China

As hybrids of narrow-line Seyfert 1 (NLS1) galaxies and blazars, γ-ray emitting NLS1s are important probes of jet physics in the high Eddington-ratio regime. Only very few of them are known to date;the majority of them below redshift z = 0.5. Here we present the identification of the γ-ray emitting AGN TXS 0943+105 (SDSS J094635.06+101706.1) as a high-redshift NLS1 galaxy. It turns out to be one of the radio-loudest NLS1s known, highly variable at all wavelengths, and shows widely extended radio emission at a (projected) > 100 kpc scale. It is a known strong γ-ray emitter with a luminous flare reported previously. At redshift z=1.004, this is the most distant γ-NLS1 known to date. Copyright © 2019, The Authors. All rights reserved.

关键词： Galaxies

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SN 2017hpa: A nearby carbon-rich type ia supernova with a large velocity gradient

arXiv

引用

arXiv 2021年

作者： Zeng, Xiangyun Wang, Xiaofeng Esamdin, Ali Pellegrino, Craig Zheng, Weikang Zhang, Jujia Mo, Jun Li, Wenxiong Howell, D. Andrew Filippenko, Alexei V. Lin, Han Brink, Thomas G. Baron, Edward A. Burke, Jamison Derkacy, James M. McCully, Curtis Hiramatsu, Daichi Hosseinzadeh, Griffin Jeffers, Benjamin T. Ross, Timothy W. Stahl, Benjamin E. Stegman, Samantha Valenti, Stefano Wang, Lifan Xiang, Danfeng Zhang, Jicheng Zhang, Tianmeng 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 Suite 102 GoletaCA93117-5575 United States Department of Astronomy University of California BerkeleyCA94720-3411 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 School of Physics and Astronomy Tel Aviv University Tel Aviv69978 Israel Miller Institute for Basic Research in Science University of California BerkeleyCA94720 United States Homer L. Dodge Department of Physics and Astronomy University of Oklahoma United States Center for Astrophysics Harvard & Smithsonian 60 Garden Street CambridgeMA02138-1516 United States Las Cumbres Observatory 6740 Cortona Drive Suite 102 GoletaCA9311-5575 United States Department of Physics University of California BerkeleyCA94720-7300 United States Department of Chemistry University of Wisconsin MadisonWI53706 United States Department of Physics University of California DavisCA95616 United States George P. and Cynthia Woods Mitchell Institute for Fundamental Physics & Astronomy Texas A&M University Department of Physics and Astronomy 4242 TAMU College StationTX77843 United States Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing100012 China

We present extensive, well-sampled optical and ultraviolet photometry and optical spectra of the Type Ia supernova (SN Ia) 2017hpa. The light curves indicate that SN 2017hpa is a normal SN Ia with an absolute peak magnitude of MmaxB ≈ −19.12 ± 0.11 mag and a post-peak decline rate ∆m15(B) = 1.02 ± 0.07 mag. According to the quasibolometric light curve, we derive a peak luminosity of 1.25 × 1043 erg s−1and a 56Ni mass of 0.63 ± 0.02 M☉. The spectral evolution of SN 2017hpa is similar to that of normal SNe Ia, while it exhibits unusually rapid velocity evolution resembling that of SN 1991bg-like SNe Ia or the high-velocity subclass of SNe Ia, with a post-peak velocity gradient of ∼ 130 ± 7 km s−1 d−1. Moreover, its early spectra (t © 2021, CC BY.

关键词： White dwarfs

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