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A QUASAR SHEDDING ITS DUST COCOON at REDSHIFT 2

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arXiv 2022年

作者： Yi, Weimin Brandt, W.N. Ni, Q. Ho, Luis C. Luo, Bin Yan, Wei Schneider, D.P. Paul, Jeremiah D. Plotkin, Richard M. Yang, Jinyi Wang, Feige He, Zhicheng Chen, Chen Wu, Xue-Bing Bai, Jin-Ming Yunnan Observatories Chinese Academy of Sciences Kunming650216 China Department of Astronomy & Astrophysics The Pennsylvania State University 525 Davey Lab University ParkPA16802 United States Institute for Gravitation and the Cosmos The Pennsylvania State University University ParkPA16802 United States Department of Physics 104 Davey Laboratory The Pennsylvania State University University ParkPA16802 United States Kavli Institute for Astronomy and Astrophysics Peking University Beijing100871 China Department of Astronomy Peking University Yi He Yuan Lu 5 Hai Dian District Beijing100871 China School of Astronomy and Space Science Nanjing University Jiangsu Nanjing210093 China Department of Physics University of Nevada RenoNV89557 United States 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 Anhui Hefei230026 China School of Physics & Astronomy Sun Yat-Sen University Zhuhai519000 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China

We present the first near-IR spectroscopy and joint analyses of multi-wavelength observations for SDSS J082747.14+425241.1, a dust-reddened, weak broad emission-line quasar (WLQ) undergoing a remarkable broad absorption line (BAL) transformation. The systemic redshift is more precisely measured to be z = 2.070 ± 0.001 using Hβ compared to z = 2.040 ± 0.003 using Mgii from the literature, signifying an extreme Mgii blueshift of 2140 ± 530 kms-1relative to Hβ. Using the Hβ-based single-epoch scaling relation with a systematic uncertainty of 0.3 dex, its black hole (BH) mass and Eddington ratio are estimated to be MBH∼ 6.1 × 108Moand λEdd∼ 0.71, indicative of being in a rapidly accreting phase. Our investigations confirm the WLQ nature and the LoBAL→HiBAL transformation, along with a factor of 2 increase in the Mgii+Fe ii emission strength and a decrease of 0.1 in E(B-V ) over two decades. The kinetic power of this LoBAL wind at R ∼15 pc from its BH is estimated to be ∼43% of the Eddington luminosity, sufficient for quasar feedback upon its host galaxy albeit with an order-of-magnitude uncertainty. This quasar provides a clear example of the long-sought scenario where LoBAL quasars are surrounded by dust cocoons, and wide-angle nuclear winds play a key role in the transition for red quasars evolving into the commonly seen blue quasars. © 2022, CC BY.

关键词： Galaxies

SN 2019va: A Type IIP Supernova with Large Influence of Nickel-56 Decay on the Plateau-phase Light Curve

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arXiv 2022年

作者： Zhang, Xinghan Wang, Xiaofeng Sai, Hanna Mo, Jun Nagy, A.P. Zhang, Jicheng Cai, Yongzhi Lin, Han Zhang, Jujia Baron, E. DerKacy, J.M. Zhang, T.-M. Li, Zhitong Graham, Melissa Huang, F. Tsinghua University Beijing100084 China Bejing Planetarium Beijing Academy of Science and Technology Beijing100044 China Department of Optics and Quantum Electronics University of Szeged Szeged6720 Hungary Department of Astronomy Beijing Normal University Beijing100875 China 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 Homer L. Dodge Department of Physics and Astronomy University of Oklahoma NormanOK73019 United States Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing10101 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing101408 China DiRAC Institute Department of Astronomy University of Washington Box 351580 U.W. SeattleWA98195 United States Department of Astronomy Shanghai Jiao Tong University Shanghai 200240 China

We present multi-band photometric and spectroscopic observations of the type II supernova, (SN) 2019va, which shows an unusually flat plateau-phase evolution in its V-band light curve. Its pseudo-bolometric light curve even shows a weak brightening towards the end of the plateau phase. These uncommon features are related to the influence of 56Ni decay on the light curve during the plateau phase, when the SN emission is usually dominated by cooling of the envelope. The inferred 56Ni mass of SN 2019va is 0.088±0.018 Mo, which is significantly larger than most SNe II. To estimate the influence of 56Ni decay on the plateau-phase light curve, we calculate the ratio (dubbed as ηNi) between the integrated time-weighted energy from 56Ni decay and that from envelope cooling within the plateau phase, obtaining a value of 0.8 for SN 2019va, which is the second largest value among SNe II that have been measured. After removing the influence of 56Ni decay on the plateau-phase light curve, we found that the progenitor/explosion parameters derived for SN 2019va are more reasonable. In addition, SN 2019va is found to have weaker metal lines in its spectra compared to other SNe IIP at similar epochs, implying a low-metallicity progenitor, which is consistent with the metal-poor environment inferred from the host-galaxy spectrum. We further discuss the possible reasons that might lead to SN 2019va-like events. Copyright © 2022, The Authors. All rights reserved.

关键词： Supernovae

Effect of Orbital Distance on the Atmospheric Escape of Exoplanets

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Chinese Astronomy and Astrophysics 2018年第1期42卷 81-100页

作者： Mo, Yang Jian-heng, Guo Yunnan Astronomical Observatory Chinese Academy of Sciences Kunming 650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China University of Chinese Academy of Sciences Beijing 100049 China

Atmospheric escape is an important sector in the evolution of planetary atmosphere, and its energy is mainly originated from the radiation of the host star at the high energy band. The radiation flux drops dramatically with the increase of orbital distance, there is a large difference of planetary atmospheric escape in different orbits, so it is necessary to study the impact of orbital distance on the atmospheric escape of an exoplanet. We consider the radiation transfer and the photochemical reactions of multiple kinds of particles to study the variation of planetary atmospheric escape with the orbital distance by using a 1-D hydrodynamic model. Due to the large differences of the spectra of host stars in different evolution stages, the Astrophysical Plasma Emission Code (APEC) in the X-Ray Spectral Fitting Package (XSPEC) is used to obtain the spectra of solar-type stars with different ages as the input spectra of the model. The results indicate that the escape rates of the exoplanets in different orbits are different significantly, and the escape mechanism is converted from the drastic hydrodynamic escape into the moderate Jeans escape as the orbital distance increases, the smaller the planetary gravitational potential, the younger the star-planet system, the larger the distance of this conversion. The correlation between the escape rate and the radiation flux decreases for the short-period exoplanets in a younger star-planet system. It is shown that the classical energy-limited escape theory is not suitable for this kind of exoplanets. These results have enriched the studies on the atmospheric escape of exoplanets, especially, extended the studies on the escape mechanism and energy conversion under different orbital distances and stellar ages. © 2018 Elsevier B.V.

关键词： hydrodynamics—planets and satellites: atmospheres—stars: solar-type—X-rays: stars

Observational signatures of the surviving donor star in the double detonation model of Type Ia supernovae

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arXiv 2021年

作者： Liu, Zheng-Wei Röpke, Friedrich K. Zeng, Yaotian Heger, Alexander Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects CAS Kunming650216 China University of Chinese Academy of Science Beijing100012 China Zentrum für Astronomie der Universität Heidelberg Institut für Theoretische Astrophysik Philosophenweg 12 Heidelberg69120 Germany Heidelberger Institut für Theoretische Studien Schloss-Wolfsbrunnenweg 35 Heidelberg69118 Germany School of Physics and Astronomy Monash University 19 Rainforest Walk VIC3800 Australia ClaytonVIC3800 Australia StromloACT2611 Australia Joint Institute for Nuclear Astrophysics National Superconducting Cyclotron Laboratory Michigan State University 1 Cyclotron Laboratory East LansingMI48824-1321 United States

The sub-Chandrasekhar mass double-detonation (DDet) scenario is a contemporary model for Type Ia supernovae (SNe Ia). The donor star in the DDet scenario is expected to survive the explosion and to be ejected at the high orbital velocity of a compact binary system. For the first time, we consistently perform three-dimensional (3D) hydrodynamical simulations of the interaction of SN ejecta with a helium (He) star companion within the DDet scenario. We map the outcomes of 3D impact simulations into one-dimensional stellar evolution codes and follow the long-term evolution of the surviving He-star companions. Our main goal is to provide the post-impact observable signatures of surviving He-star companions of DDet SNe Ia, which will support the search for such companions in future observations. Such surviving companions are ejected with high velocities of up to about 930 km s-1. We find that our surviving He-star companions become significantly overluminous for about 106yr during the thermal re-equilibration phase. After the star re-establishes thermal equilibrium, its observational properties are not sensitive to the details of the ejecta-donor interaction. We apply our results to hypervelocity star US 708, which is the fastest unbound star in our Galaxy, travelling with a velocity of about 1,200 kms-1, making it natural candidate for an ejected donor remnant of a DDet SN Ia. We find that a He-star donor with an initial mass of 0.5Mois needed to explain the observed properties of US 708. Based on our detailed binary evolution calculations, however, the progenitor system with such a massive He-star donor cannot get close enough at the moment of SN explosion to explain the high velocity of US 708. Instead, if US 708 is indeed the surviving He-star donor of a DDet SN Ia, it would require the entire pre-SN progenitor binary to travel at a velocity of about 400 kms-1. It could, for example, have been ejected from a globular cluster in the direction of the current motion of

关键词： Detonation

Red eminence: The intermediate-luminosity red transient AT 2022fnm

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arXiv 2024年

作者： Moran, S. Kotak, R. Fraser, M. Pastorello, A. Cai, Y.-Z. Valerin, G. Mattila, S. Cappellaro, E. Kravtsov, T. Gutiérrez, C.P. Elias-Rosa, N. Reguitti, A. Lundqvist, P. Filippenko, A.V. Brink, T.G. Wang, X.-F. Department of Physics and Astronomy University of Turku Vesilinnantie 5 FI-20500 Finland School of Physics University College Dublin Belfield Dublin 4 Ireland INAF Osservatorio Astronomico di Padova Vicolo dell’Osservatorio 5 PadovaI-35122 Italy 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 Dipartimento di Fisica e Astronomia "G. Galilei" Università degli Studi di Padova Vicolo dell’Osservatorio 3 PadovaI-35122 Italy School of Sciences European University Cyprus Diogenes Street Engomi Nicosia1516 Cyprus European Southern Observatory Alonso de Córdova 3107 Casilla 19 Santiago Chile Gran Capità 2-4 Edifici Nexus Desp. 201 BarcelonaE-08034 Spain Campus UAB Carrer de Can Magrans s/n BarcelonaE-08193 Spain INAF Osservatorio Astronomico di Brera Via E. Bianchi 46 LC MerateI-23807 Italy Oskar Klein Centre Department of Astronomy Stockholm University Albanova University Centre StockholmSE-106 91 Sweden Department of Astronomy University of California BerkeleyCA94720-3411 United States Physics Department Tsinghua University Beijing100084 China Beijing Planetarium Beijing Academy of Science and Technology Beijing100044 China

We present results from a five-month-long observing campaign of the unusual transient AT 2022fnm, which displays properties common to both luminous red novae (LRNe) and intermediate-luminosity red transients (ILRTs). Although its photometric evolution is broadly consistent with that of LRNe, no second peak is apparent in its light curve, and its spectral properties are more reminiscent of ILRTs. It has a fairly rapid rise time of 5.3±1.5 d, reaching a peak absolute magnitude of −12.7±0.1 (in the ATLAS o band). We find some evidence for circumstellar interaction, and a near-infrared excess becomes apparent at approximately +100 d after discovery. We attribute this to a dust echo. Finally, from an analytical diffusion toy model, we attempted to reproduce the pseudo-bolometric light curve and find that a mass of ∼4 M☉ is needed. Overall, the characteristics of AT 2022fnm are consistent with a weak stellar eruption or an explosion reminiscent of low-energy type IIP supernovae, which is compatible with expectations for ILRTs. © 2024, CC BY.

关键词： Luminance

The formation of type Ia supernovae from carbon-oxygen-silicon white dwarfs

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arXiv 2020年

作者： Wu, Chengyuan Wang, Bo. Wang, Xiaofeng Maeda, Keiichi Mazzali, Paolo Tsinghua University Beijing100084 China Key Laboratory for the Structure and Evolution of Celestial Objects Yunnan Observatories CAS Kunming650216 China Department of Astronomy Kyoto University Kitashirakawa-Oiwake-cho Sakyo-ku Kyoto606-8502 Japan Astrophysics Research Institute Liverpool John Moores University IC2 Liverpool Science Park 146 Brownlow Hill LiverpoolL3 5RF United Kingdom

The carbon-oxygen white dwarf (CO WD) + He star channel has been thought to be one of the promising scnarios to produce young type Ia supernovae (SNe Ia). Previous studies found that if the mass-accretion rate is greater than a critical value, the He-accreting CO WD will undergo inwardly propagating (off-centre) carbon ignition when it increases its mass close to the Chandrasekhar limit. The inwardly propagating carbon flame was supposed to reach the centre by previous works, leading to the production of an oxygen-neon (ONe) WD that may collapse into a neutron star but not an SN Ia. However, it is still uncertain how the carbon flame propagates under the effect of mixing mechanisms. In the present work, we aim to investigate the off-centre carbon burning of the He-accreting CO WDs by considering the effect of convective mixing. We found that the temperature of the flame is high enough to burn the carbon into silicon-group elements in the outer part of the CO core even if the convective overshooting is considered, but the flame would quench somewhere inside the WD, resulting in the formation of a C-O-Si WD. Owing to the inefficiency of thermohaline mixing, the C-O-Si WD may explode as an SN Ia if it continues to grow in mass. Our radiation transfer simulations show that the SN ejecta with the silicon-rich outer layer will form high-velocity absorption lines in Si II, leading to some similarities to a class of the high-velocity SNe Ia in the spectral evolution. We estimate that the birthrate of SNe Ia with Si-rich envelope is ∼1 × 10−4 yr−1 in our galaxy. Copyright © 2020, The Authors. All rights reserved.

关键词： White dwarfs

Gravitational wave radiation of double degenerates with extremely low-mass WD companions

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arXiv 2020年

作者： Li, Zhenwei Chen, Xuefei Chen, Hai-Liang Li, Jiao Yu, Shenghua Han, Zhanwen Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Science China University of the Chinese Academy of Science Yuquan Road 19 Shijingshan Block Beijing100049 China Center for Astronomical Mega-Science Chinese Academy of Science 20A Datun Road Chaoyang District Beijing100012 China National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China

Double Degenerate systems (DDs) are supposed to be significant gravitational wave (GW) sources for future space-based gravitational-wave detectors, e.g., Laser Interferometer Space Antenna (LISA). Recently, one type of DDs with Extremely low-mass WD (ELM WD;. 0.30 M) companions has been largely found in the ELM Survey. They have very short orbital periods and are therefore important sources for LISA detection. Besides, due to the thick envelope of ELM WDs compared with massive WDs (e.g. CO WDs), they are much easier to be found by the combination of electromagnetic (EM) and GW observations. In this paper, we first obtain the population of ELM WDs in DDs with considering the detailed evolutionary tracks of ELM WDs, and then analyse the GW radiation of these systems. We found that about 6 × 103 sources could be solely detected by LISA, including ∼ 2 × 103 chirping sources, and ∼ 13 (∼ 107) more sources are expected to be detected by both LISA and ELM Survey (Gaia). Copyright © 2020, The Authors. All rights reserved.

关键词： Gravity waves

A comparison of star formation history between NGC 300 and M33

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Proceedings of the International Astronomical Union 2020年第S341期15卷 275-276页

作者： Xiaoyu Kang Fenghui Zhang Ruixiang Chang Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming 650216 P. R. China email: kxyysl@*** Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming 650216 P. R. China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing 100012 P. R. China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory CAS 80 Nandan Road Shanghai 200030 China

NGC 300 is a near-optical twin of the Local Group galaxy M33, which are benchmarks for understanding late-type spiral galaxies. They are two bulgeless and low-mass spiral galaxies in different environments. In order to explore the common properties and differences between the two nearby low-mass systems, we first use the simple chemical evolution model to explore the star formation history (SFH) of NGC300 and M33, and then compare the feasible model predicted SFH of NGC 300 with that of M33. Through comparing the SFHs between them, it can be found that the mean stellar age of NGC 300 is older than that of M33, there is a recent lack of primordial gas infall onto the disk of NGC 300, recent star formation along the disk of NGC 300 is less active than that of M33, and the local environment may play a key role in the secular evolution of a galaxy.

关键词： galaxies: evolution galaxies: spiral galaxies: individual: NGC 300 and M33

The black hole spin in coalescing binary black holes and high-mass X-ray binaries

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Proceedings of the International Astronomical Union 2019年第S346期14卷 426-432页

作者： Qin, Y. Fragos, T. Meynet, G. Marchant, P. Kalogera, V. Andrews, J. Sørensen, M. Song, H.F. Geneva Observatory University of Geneva Switzerland Center for Interdisciplinary Exploration and Research in Astrophysics Department of Physics and Astrophysics Northwestern University Evanston 60208 IL United States Foundation for Research and Technology-Hellas IESL Voutes Heraklion 71110 Greece Physics Department Institute of Theoretical and Computational Physics University of Crete Heraklion Crete 71003 Greece College of Physics Guizhou University Guiyang City Guizhou Province 550025 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China

The six LIGO detections of merging black holes (BHs) allowed to infer slow spin values for the two pre-merging BHs. The three cases where the spins of the BHs can be determined in high-mass X-ray binaries (HMXBs) show that those BHs have high spin values. We discuss here scenarios explaining these differences in spin properties in these two classes of object. © International Astronomical Union 2019.

关键词： Binaries: Close binary stars black hole gravitational waves X-rays: Binaries