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

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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

Why are peculiar type ia supernovae more likely to show the signature of a single-degenerate model?

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arXiv 2018年

作者： Meng, Xiang-Cun Han, Zhan-Wen 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

Although type Ia supernovae (SNe Ia) are very useful in many astrophysical fields, their exact progenitor nature is still unclear. A basic method to distinguish the different progenitor models is to search the signal from the single-degenerate (SD) model, e.g., the signal for the existence of a nondegenerate companion before or after supernova explosion. Observationally, some SNe Ia show such signals, while the others do not. Here, we propose a universal model to explain these observations based on the spin-up/spin-down model, in which a white dwarf (WD) will experience a spin-down phase before supernova explosion, and the spin-down timescale is determined by its initial mass, i.e., the more massive the initial WD, the shorter the spin-down timescale and then the more likely the SN Ia is to show the SD signature. Therefore, our model predicts that the SNe Ia from hybrid carbon-oxygen-neon WDs are more likely to show the SD signature observationally, as some peculiar SNe Ia showed. Copyright © 2018, The Authors. All rights reserved.

关键词： White dwarfs

The metamorphosis of the Type Ib SN 2019yvr: late-time interaction

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arXiv 2024年

作者： Ferrari, Lucía Folatelli, Gastón Kuncarayakti, Hanindyo Stritzinger, Maximilian Maeda, Keiichi Bersten, Melina Román Aguilar, Lili M. Sáez, M. Manuela Dessart, Luc Lundqvist, Peter Mazzali, Paolo Nagao, Takashi Ashall, Chris Bose, Subhash Brennan, S.J. Cai, Y.-Z. Handberg, Rasmus Holmbo, Simon Karamehmetoglu, Emir Pastorello, Andrea Reguitti, Andrea Anderson, Joseph Chen, Ting-Wan Galbany, Lluís Gromadzki, Mariusz Gutiérrez, Claudia P. Inserra, Cosimo Kankare, Erkki Müller Bravo, Tomás E. Mattila, Seppo Nicholl, Matt Pignata, Giuliano Sollerman, Jesper Srivastav, Shubham Young, David R. Instituto de Astrofísica de La Plata CONICET Argentina Facultad de Ciencias Astronómicas y Geofísicas Universidad Nacional de La Plata Paseo del Bosque S La PlataN B1900FWA Argentina The University of Tokyo Chiba Kashiwa277-8583 Japan Department of Physics and Astronomy University of Turku TurkuFI-20014 Finland University of Turku FI-20014 Finland Department of Physics and Astronomy Aarhus University Ny Munkegade 120 Aarhus CDK-8000 Denmark Department of Astronomy Kyoto University Kitashirakawa-Oiwake-cho Sakyo-ku Kyoto606-8502 Japan RIKEN Saitama Wako351-0198 Japan Department of Physics University of California BerkeleyCA94720 United States Institut d’Astrophysique de Paris CNRS-Sorbonne Université 98 bis boulevard Arago Paris75014 France The Oskar Klein Centre Department of Astronomy Stockholm University AlbaNova StockholmSE-10691 Sweden Max-Planck-Institut für Astrophysik Karl-Schwarzschild-Str. 1 GarchingD-85748 Germany Astrophysics Research Institute Liverpool John Moores University 146 Brownlow Hill LiverpoolL3 5RF United Kingdom Aalto University Metsähovi Radio Observatory Metsähovintie 114 Kylmälä02540 Finland Aalto University Department of Electronics and Nanoengineering P.O. BOX 15500 AaltoFI-00076 Finland Department of Physics Virginia Tech BlacksburgVA24061 United States Department of Astronomy The Ohio State University 140 W. 18th Avenue ColumbusOH43210 United States Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China INAF - Osservatorio Astronomico di Padova Vicolo dell’Osservatorio 5 Padova35122 Italy Merate23807 Italy European Southern Observatory Alonso de Córdova 3107 Casilla 19 Santiago Chile Graduate Institute of Astronomy National Central University 300 Jhongda Road Jhongli32001

We present observational evidence of late-time interaction between the ejecta of the hydrogen-poor Type Ib supernova (SN) 2019yvr and hydrogen-rich circumstellar material (CSM), similar to the Type Ib SN 2014C. A narrow Hα emission line appears simultaneously with a break in the light-curve decline rate at around 80 − 100 d after explosion. From the interaction delay and the ejecta velocity, under the assumption that the CSM is detached from the progenitor, we estimate the CSM inner radius to be located at ∼ 6.5 − 9.1 × 1015 cm. The Hαemission line persists throughout the nebular phase at least up to +420 d post-explosion, with a full width at half maximum (FWHM) of ∼ 2000 km s−1. Assuming a steady mass loss, the estimated mass-loss rate from the luminosity of the Hα line is ∼ 3 − 7 × 10−5 M☉ yr−1. From hydrodynamical modeling and analysis of the nebular spectra, we find a progenitor He-core mass of 3 − 4 M, which would imply an initial mass of 13 − 15 M☉Our result supports the case of a relatively low mass progenitor possibly in a binary system as opposed to a higher mass single star undergoing an LBV phase. Copyright © 2024, The Authors. All rights reserved.

关键词： Supernovae

Still brighter than pre-explosion, SN 2012Z did not disappear: Comparing hubble space telescope observations a decade apart

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arXiv 2021年

作者： Mccully, Curtis Jha, Saurabh W. Scalzo, Richard A. Howell, D. Andrew Foley, Ryan J. Zeng, Yaotian Liu, Zheng-Wei Hosseinzadeh, Griffin Bildsten, Lars Riess, Adam G. Kirshner, Robert P. Marion, G.H. Camacho-Neves, Yssavo Las Cumbres Observatory 6740 Cortona Dr Ste 102 GoletaCA93117-5575 United States Department of Physics University of California Santa BarbaraCA93106-9530 United States Department of Physics and Astronomy Rutgers The State University of New Jersey 136 Frelinghuysen Road PiscatawayNJ08854 United States School of Mathematics and Statistics The University of Sydney CamperdownNSW2006 Australia Centre for Translational Data Science University of Sydney DarlingtonNSW2008 Australia Department of Astronomy and Astrophysics University of California Santa CruzCA92064 United States Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming650216 China University of Chinese Academy of Science Beijing100012 China Center for Astronomical Mega-Science CAS Beijing100012 China Center for Astrophysics - Harvard and Smithsonian 60 Garden Street CambridgeMA02138-1516 United States Kavli Institute for Theoretical Physics University of California Santa BarbaraCA93106 United States Space Telescope Science Institute 3700 San Martin Drive BaltimoreMD21218 United States Department of Physics and Astronomy Johns Hopkins University BaltimoreMD21218 United States Gordon and Betty Moore Foundation 1661 Page Mill Road Palo AltoCA94304 United States University of Texas at Austin 1 University Station C1400 AustinTX78712-0259 United States

Type Iax supernovae represent the largest class of peculiar white-dwarf supernovae. The type Iax SN 2012Z in NGC 1309 is the only white dwarf supernova with a detected progenitor system in pre-explosion observations. Deep Hubble Space Telescope images taken before SN 2012Z show a luminous, blue source that we have interpreted as a helium-star companion (donor) to the exploding white dwarf. We present here late-time HST observations taken ∼1400 days after the explosion to test this model. We find the SN light curve can empirically be fit by an exponential decay model in magnitude units. The fitted asymptotic brightness is within 10% of our latest measurements and approximately twice the brightness of the pre-explosion source. The decline of the light curve is too slow to be powered by 56Co or 57Co decay: if radioactive decay is the dominate power source, it must be from longer half-life species like 55Fe. Interaction with circumstellar material may contribute to the light curve, as may shock heating of the companion star. Companion-star models underpredict the observed flux in the optical, producing most of their flux in the UV at these epochs. A radioactively-heated bound remnant, left after only a partial disruption of the white dwarf, is also capable of producing the observed excess late-time flux. Our analysis suggests that the total ejecta + remnant mass is consistent with the Chandrasekhar mass for a range of type Iax supernovae. Copyright © 2021, The Authors. All rights reserved.

关键词： Supernovae

Past and future of the central double-degenerate core of Henize 2-428

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arXiv 2018年

作者： Wu, Dong-Hao Liu, Dong-Dong Wang, Bo Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China University of Chinese Academy of Sciences Beijing100049 China Center for Astronomical Mega-Science Chinese Academy of Sciences Beijing100012 China

It has been suggested that SNe Ia could be produced in the condition of the violent merger scenario of the double-degenerate model, in which a thermonuclear explosion could be produced when the merging of double carbon-oxygen white dwarfs (CO WDs) is still ongoing. It has been recently found that the nucleus of the bipolar planetary nebula Henize 2-428 consists of double CO WDs that have a total mass of ∼1.76Mo, a mass ratio of ∼1 and an orbital period of ∼4.2 hours, which is the first and only discovered progenitor candidate of SNe Ia predicted by the violent merger scenario. In this work, we aim to reproduce the evolutionary history of the central double COWDs of Henize 2-428. We find that the planetary nebula Henize 2-428 may originate from a primordial binary that have a ∼5.4Moprimary and a ∼2.7Mosecondary with an initial orbital period of ∼15.9 days. The double CO WDs are formed after the primordial binary experiencing two Roche-lobe overflows and two common-envelope ejection processes. According to our calculations, it takes about ∼840Myr for the double CO WDs to merge and form an SN Ia driven by the gravitational wave radiation after their birth. To produce the current status of Henize 2-428, a large common-envelope parameter is needed. We also estimate that the rate of SNe Ia from the violent merger scenario is at most 2.9 × 10-4yr-1, and that the delay time is in the range of ∼90Myr to the Hubble time. Copyright © 2018, The Authors. All rights reserved.

关键词： Merging

The single-degenerate model for the progenitors of accretion-induced collapse events

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arXiv 2018年

作者： Wang, Bo 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 University of Chinese Academy of Sciences Beijing100049 China

It has been suggested that the accretion-induced collapse (AIC) of an oxygen-neon white dwarf (ONe WD) to a neutron star is a theoretically predicted outcome in stellar evolution, likely relating to the formation of some neutron star systems. However, the progenitor models of AIC events are still not well studied, and recent studies indicated that CO WD+He star systems may also contribute to the formation of neutron star systems through AIC process when off-centre carbon ignition happens on the surface of the CO WD. In this work, I studied the single-degenerate (SD) model of AIC events in a systematic way, including the contribution of the CO WD+He star channel and the ONe WD+MS/RG/He star channels. Firstly, I gave the initial parameter space of these SD channels for producing AIC events in the orbital period–secondary mass plane based on detailed binary evolution computations. Then, according to a binary population synthesis approach, I gave the rates and delay times of AIC events for these SD channels based on their initial parameter space. I found that the rates of AIC events in our galaxy are in the range of ∼ 0.3 − 0.9 × 10−3 yr−1, and that their delay times are >30 Myr. I also found that the ONe WD+He star channel is the main way to produce AIC events, and that the CO WD+He star channel cannot be ignored when studying the progenitors of AIC events. Copyright © 2018, The Authors. All rights reserved.

关键词： White dwarfs

The Pulsation Induced by Mass Transfer in Critically Rotating Stars

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Chinese Physics Letters 2016年第9期33卷 136-139页

作者：王江涛宋汉峰 College of Science Guizhou University Geneva Observatory University of Geneva Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences

The structural characteristics of the critically rotating accretor in binaries are investigated during rapid mass transfer. It is found that the accretor is subjected to periodic pulsation due to accretions and rejections of mass and angular momentum. Tile gainer attempts to attain both hydrostatic and thermal balances. This physical process can cause tile thermal structure of the accreting star to fluctuate with a period of ~ 0.19 y. Stellar wind can be enhanced by a factor of ~1.25 ×10^4 when the accretor approaches break-down velocity. Surface entropy and density decrease with the increase of the stellar radius due to the fact that rapid rotation leads to a reduction in the number density and surface temperature. The rotational energy has the same trend as stellar radius due to stellar expansion. Surface opacity which is extremely sensitive to surface temperature has an opposite trend to stellar radius. Moreover, the rate of nuclear energy must be adjusted due to mass removal or accretion at the stellar surface.

关键词： of is on it as The Pulsation Induced by Mass Transfer in Critically Rotating Stars in by

An Empirical Fit for Viscoelastic Simulations of Tertiary Tides

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arXiv 2019年

作者： Gao, Yan Toonen, Silvia Grishin, Evgeni Comerford, Tom Kruckow, Matthias U. Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China University of Chinese Academy of Sciences Anton Pannekoek Institute for Astronomy University Of Amsterdam Amsterdam1090 GE Netherlands Institute for Gravitational Wave Astronomy School of Physics and Astronomy University of Birmingham BirminghamB15 2TT United Kingdom Physics Department Technion - Israel Institute of Technology Haifa3200003 Israel Institute of Astronomy University of Camridge Madingley Road CambridgeCB3 OHA United Kingdom

Tertiary tides (TTs), or the continuous tidal distortion of the tertiary in a hierarchical triple system, can extract energy from the inner binary, inducing within it a proclivity to merge. Despite previous work on the subject, which established that it is significant for certain close triple systems, it is still not a well-understood process. A portion of our ignorance in this regard stems from our inability to integrate a simulation of this phenomenon into conventional stellar evolution codes, since full calculations of these tidal interactions are computationally expensive on stellar evolution timescales. Thus, to attain a better understanding of how these TTs act on longer timescales, an empirical expression of its effects as a function of parameters of the triple system involved is required. In our work, we evaluate the rate at which TTs extract energy from the inner binary within a series of constructed hierarchical triple systems under varying parameters, and study the rate at which the inner binary orbital separation shrinks as a function of those parameters. We find that this rate varies little with the absolute values of the masses of the three component objects, but is very sensitive to the mass ratio of the inner binary q, the tertiary radius R3, the inner binary orbital separation a1, the outer orbital separation a2, and the viscoelastic relaxation time of the tertiary τ. More specifically, we find that the percentage by which a1 shrinks per unit time can be reasonably approximated by (1/a1)(da1/dt)=(2.22×10−8yrs−1) 4q (1 + q)−2 (R3/100R)5.2(a1/0.2AU)4.8(a2/2AU)−10.2 (τ/0.534yrs)−1.0. We also provide tests of how precise this fitting function is. Copyright © 2019, The Authors. All rights reserved.

关键词： Astrophysics

The correlations between optical/UV broad lines and X-ray emission for a large sample of quasars

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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