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Multi-band analyses of the bright GRB 230812B and the associated SN2023pel

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arXiv 2023年

作者： Hussenot-Desenonges, T. Wouters, T. Guessoum, N. Abdi, I. Abulwfa, A. Adami, C. Fernández, J.F. Agüí Ahumada, T. Aivazyan, V. Akl, D. Anand, S. Andrade, C.M. Antier, S. Ata, S.A. D’Avanzo, P. Azzam, Y.A. Baransky, A. Basa, S. Blazek, M. Bendjoya, P. Beradze, S. Boumis, P. Bremer, M. Brivio, R. Buat, V. Bulla, M. Burkhonov, O. Burns, E. Cenko, S.B. Coughlin, M.W. Corradi, W. Daigne, F. Dietrich, T. Dornic, D. Ducoin, J.-G. Duverne, P.-A. Elhosseiny, E.G. Elnagahy, F.I. El-Sadek, M.A. Ferro, M. Le Floc’h, E. Freeberg, M. Fynbo, J.P.U. Götz, D. Gurbanov, E. Hamed, G.M. Hasanov, E. Healy, B.F. Heintz, K.E. Hello, P. Inasaridze, R. Iskandar, A. Ismailov, N. Izzo, L. Jhawar, S. du Laz, T. Jegou Kamel, T.M. Karpov, S. Klotz, A. Koulouridis, E. Kuin, N.P. Kochiashvili, N. Leonini, S. Lu, K.-X. Malesani, D.B. Mašek, M. Mao, J. Melandri, A. Mihov, B.M. Natsvlishvili, R. Navarete, F. Nedora, V. Nicolas, J. Odeh, M. Palmerio, J. Pang, P.T.H. De Pasquale, M. Peng, H.W. Pormente, S. Peloton, J. Pradier, T. Pyshna, O. Rajabov, Y. Rakotondrainibe, N.A. Rivet, J.-P. Rousselot, L. Saccardi, A. Sasaki, N. Schneider, B. Serrau, M. Shokry, A. Slavcheva-Mihova, L. Simon, A. Sokoliuk, O. Srinivasaragavan, G. Strausbaugh, R. Takey, A. Tanvir, N.R. Thöne, C.C. Tillayev, Y. Tosta e Melo, I. Turpin, D. de Ugarte Postigo, A. Vasylenko, V. Vergani, S.D. Vidadi, Z. Xu, D. Wang, L.T. Wang, X.F. Winters, J.M. Zhang, X.-L. Zhu, Z. IJCLab Univ Paris-Saclay CNRS IN2P3 Orsay France Nikhef Science Park 105 Amsterdam1098 XG Netherlands Utrecht University Princetonplein 1 Utrecht3584 CC Netherlands Physics Department American University of Sharjah Sharjah United Arab Emirates 1 El-marsad St. Helwan Cairo11421 Egypt Aix Marseille Univ CNRS CNES LAM Marseille France Instituto de Astrofísica de Andalucía Glorieta de la Astronomía s/n Granada18008 Spain Cahill Center for Astrophysics California Institute of Technology PasadenaCA91125 United States E. Kharadze Georgian National Astrophysical Observatory Mt. Kanobili Abastumani Adigeni0301 Georgia Samtskhe-Javakheti State University Rustaveli Str. 113 Akhaltsikhe0080 Georgia School of Physics and Astronomy University of Minnesota MinneapolisMN55455 United States Observatoire de la Côte d’Azur Université Côte d’Azur Boulevard de l’Observatoire Nice06304 France INAF–Osservatorio Astronomico di Brera Via E. Bianchi 46 LC Merate23807 Italy Astronomical Observatory Taras Shevchenko National University of Kyiv Observatorna Str. 3 Kyiv04053 Ukraine CEICO Institute of Physics The Czech Academy of Sciences Na Slovance 1999/2 PrahaCZ-182 21 Czech Republic Centro Astronómico Hispano en Andalucía Observatorio de Calar Alto Sierra de los Filabres Gérgal Almería04550 Spain Laboratoire J.-L. Lagrange Université de Nice Sophia-Antipolis CNRS Observatoire de la Côte d’Azur Nice06304 France National Observatory of Athens Institute for Astronomy Astrophysics Space Applications and Remote Sensing Greece Institut de Radioastronomie Millimétrique France Università degli Studi dell’Insubria Dipartimento di Scienza e Alta Tecnologia Via Valleggio 11 Como22100 Italy Department of Physics and Earth Science University of Ferrara via Saragat 1 FerraraI-44122 Italy INFN Sezione di Ferrara via Saragat 1 FerraraI-44122 Italy INAF Osservatorio Astronomico d’Abruzzo via Mentore Maggini snc TeramoI-64100 Italy Ulugh Beg Astrono

GRB 230812B is a bright and relatively nearby (z = 0.36) long gamma-ray burst (GRB) that has generated significant interest in the community and has thus been observed over the entire electromagnetic spectrum. We report over 80 observations in X-ray, ultraviolet, optical, infrared, and sub-millimeter bands from the GRANDMA (Global Rapid Advanced Network for Multi-messenger Addicts) network of observatories and from observational partners. Adding complementary data from the literature, we then derive essential physical parameters associated with the ejecta and external properties (i.e. the geometry and environment) of the GRB and compare with other analyses of this event. We spectroscopically confirm the presence of an associated supernova, SN2023pel, and we derive a photospheric expansion velocity of v ∼ 17×103 km s-1. We analyze the photometric data first using empirical fits of the flux and then with full Bayesian Inference. We again strongly establish the presence of a supernova in the data, with a maximum (pseudo-)bolometric luminosity of 5.75×1042 erg/s, at 15.76+0.81-1.21 days (in the observer frame) after the trigger, with a half-max time width of 22.0 days. We compare these values with those of SN1998bw, SN2006aj, and SN2013dx. Our best-fit model favours a very low density environment (log10(nISM/cm-3) = -2.38+1.45-1.60) and small values for the jet’s core angle θcore = 1.54+1.02-0.81 deg and viewing angle θobs = 0.76+1.29-0.76 deg. GRB 230812B is thus one of the best observed afterglows with a distinctive supernova bump. © 2023, CC BY.

关键词： Supernovae

Observations of type ia supernova 2014j for nearly 900 days and constraints on its progenitor system

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arXiv 2019年

作者： Li, Wenxiong Wang, Xiaofeng Hu, Maokai Yang, Yi Zhang, Jujia Mo, Jun Chen, Zhihao Zhang, Tianmeng Benetti, Stefano Cappellaro, Enrico Elias-Rosa, Nancy Isern, Jordi Morales-Garoffolo, Antonia Huang, Fang Ochner, Paolo Pastorello, Andrea Reguitti, Andrea Tartaglia, Leonardo Terreran, Giacomo Tomasella, Lina Wang, Lifan Tsinghua University Beijing100084 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing210034 China Department of Particle Physics and Astrophysics Weizmann Institute of Science Rehovot76100 Israel Yunnan Astronomical Observatory of China Chinese Academy of Sciences Kunming650011 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 China National Astronomical Observatory of China Chinese Academy of Sciences Beijing100012 China INAF - Osservatorio Astronomico di Padova Vicolo dell’Osservatorio 5 Padova35122 Italy Campus UAB Carrer de Can Magrans s/n Barcelona08193 Spain c/Gran Capitá 2-4 Edif. Nexus 201 Barcelona08034 Spain Department of Applied Physics University of Cádiz Campus of Puerto Real E-11510 Cádiz Spain Department of Astronomy School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Dipartimento di Fisica e Astronomia G. Galilei Universita’ di Padova Vicolo dell’Osservaotio 3 Padova35122 Italy Departamento de Ciencias Fisicas Universidad Andrés Bello Fernandez Concha Santiago700 Chile Department of Astronomy Stockholm University StockholmSE 10691 Sweden Department of Physics and Astronomy Northwestern University EvanstonIL60208 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

We present extensive ground-based and Hubble Space Telescope (HST) photometry of the highly reddened, very nearby type Ia supernova (SN Ia) 2014J in M82, covering the phases from 9 days before to about 900 days after the B-band maximum. SN 2014J is similar to other normal SNe Ia near the maximum light, but it shows flux excess in the B band in the early nebular phase. This excess flux emission can be due to light scattering by some structures of circumstellar materials located at a few 1017 cm, consistent with a single degenerate progenitor system or a double degenerate progenitor system with mass outflows in the final evolution or magnetically driven winds around the binary system. At t∼+300 to ∼+500 days past the B-band maximum, the light Copyright © 2019, The Authors. All rights reserved.

关键词： Supernovae

SN 2021csp - The explosion of a stripped envelope star within a H and He-poor circumstellar medium

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arXiv 2021年

作者： Fraser, Morgan Stritzinger, Maximilian D. Brennan, Seán J. Pastorello, Andrea Cai, Yongzhi Piro, Anthony L. Ashall, Chris Brown, Peter Burns, Christopher R. Elias-Rosa, Nancy Filippenko, Alexei V. Galbany, L. Hsiao, E.Y. Jha, Saurabh W. Kotak, Rubina Moran, Shane Morrell, Nidia Ochner, Paolo Phillips, M.M. Reguitti, Andrea Shappee, B.J. Tomasella, Lina Tucker, Michael Wang, Xiaofeng Zhang, Ju-Jia Anderson, J.P. Barna, Tyler Baron, E. Benetti, Stefano Bersten, Melina C. Brink, Thomas G. Camacho-Neves, Yssavo Davis, Scott Dettman, Kyle G. Folatelli, Gaston Gutiérrez, Claudia P. Höflich, Peter Holoien, Thomas W.-S. Kankare, Erkki Kuncarayakti, Hanindyo Kwok, Lindsey Kumar, Sahana Lu, Jing Mazzali, Paolo Shahbandeh, Melissa Suntzeff, Nicholas B. Taubenberger, Stefan Tinyanont, Samaporn Yan, Shengyu Yang, Yi Zheng, WeiKang School of Physics University College Dublin Dublin 4 Belfield Ireland Department of Physics and Astronomy Aarhus University Ny Munkegade 120 Aarhus CDK-8000 Denmark INAF – Osservatorio Astronomico di Padova Vicolo dell’Osservatorio 5 PadovaI-35122 Italy Tsinghua University Beijing100084 China The Observatories of the Carnegie Institution for Science 813 Santa Barbara St. PasadenaCA91101 United States Institute for Astronomy University of Hawai’i 2680 Woodlawn Drive HonoluluHI96822 United States George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy Department of Physics and Astronomy Texas A & M University College StationTX77843 United States Campus UAB Carrer de Can Magrans s/n BarcelonaE-08193 Spain Department of Astronomy University of California BerkeleyCA94720-3411 United States Miller Institute for Basic Research in Science University of California BerkeleyCA94720 United States Department of Physics Florida State University 77 Chieftain Way TallahasseeFL32306 United States Department of Physics and Astronomy Rutgers the State University of New Jersey 136 Frelinghuysen Road PiscatawayNJ08854 United States Tuorla Observatory Department of Physics and Astronomy University of Turku Turku20014 Finland Carnegie Observatories Las Campanas Observatory Casilla 601 La Serena Chile Dipartimento di Fisica e Astronomia Università di Padova Vicolo Osservatorio 2 Padova35122 Italy Departamento de Ciencias Fisicas Universidad Andres Bello Avda. Republica 252 Santiago Chile Nuncio Monseñor Sotero Sanz 100 Providencia Santiago Chile Beijing Planetarium Beijing Academy of Science and Technology Beijing100044 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 European Southern Observatory Alonso de Córdova 3107 Casilla 19 Santiago Chile Homer L. Dodge Departme

We present observations of SN 2021csp, a unique supernova (SN) which displays evidence for interaction with H- and He- poor circumstellar material (CSM) at early times. Using high-cadence spectroscopy taken over the first week after explosion, we show that the spectra of SN 2021csp are dominated by C III lines with a velocity of 1800 km s−1. We associate this emission with CSM lost by the progenitor prior to explosion. Subsequently, the SN displays narrow He lines before metamorphosing into a broad-lined Type Ic SN. We model the bolometric light curve of SN 2021csp, and show that it is consistent with the energetic (4 × 1051 erg) explosion of a stripped star, producing 0.4 M of 56Ni within a ∼ 1 M shell of CSM extending out to 400 R. Copyright © 2021, The Authors. All rights reserved.

关键词： Supernovae

Physical Properties and Catalogue of EW-type Eclipsing Binaries Observed by LAMOST

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arXiv 2017年

作者： Qian, S.-B. He, J.-J. Zhang, J. Zhu, L.-Y. Shi, X.-D. Zhao, E.-G. Zhou, X. P.O. Box 110 Kunming650011 Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences P. O. Box 110 Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang Dis-trict Beijing100012 China University of the Chinese Academy of Sciences Yuquan Road 19# Sijingshang Block Beijing100049 China

EW-type eclipsing binaries (hereafter EWs) are strong interacting systems where both component stars are usually filling the critical Roche lobes and are sharing a common envelope. Numerous EWs were discovered by several deep photometric survey and there are about 40785 EW-type binary systems listed in the international variable star index (VSX) by March 13, 2017. 7938 of them were observed by LAMOST by November 30, 2016 and their spectral types were given. Stellar atmospheric parameters of 5363 EW-type binary stars were determined based on good spectroscopic observations. In the paper, those EWs were catalogued and their properties are analyzed. The distributions of the orbital period (P), the effect temperature (T), the gravitational acceleration (Log(g)), the metallicity ([Fe/H]) and the radial velocity (RV) are presented for those observed EW-type systems. It is shown that about 80.6% sample stars have metallicity below zero indicating that EW-type systems are old stellar population. This is in agreement with the the conclusion that the EW binaries are formed from moderately close binaries through angular momentum loss via magnetic braking that takes a few hundred million to a few billion years. The unusual high metallicities of a few percent of EWs may be caused by contaminating of material from the evolution of unseen neutron stars and black holes in the systems. The correlations between the orbital period and the effect temperature, the gravitational acceleration and the metallicity are presented and their scatters are mainly caused by (i) the presence of the third bodies and (ii) the wrong determined periods sometimes. It is shown that some EW contain evolved component stars and the physical properties of EWs are mainly depending on their orbital periods. It is found that the extremely short-period EWs may be older than their long-period cousins because they have lower metallicities. This reveals that they have a longer timescale of pre-contact evolution and

关键词： Astrophysics

Physical properties and evolutionary states of EA-type eclipsing binaries observed by LAMOST

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arXiv 2017年

作者： Qian, S.-B. Zhang, J. He, J.-J. Zhu, L.-Y. Zhao, E.-G. Shi, X.-D. Zhou, X. Han, Z.-T. P.O. Box 110 Kunming650011 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences P.O. Box 110 Kunming650011 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 China University of the Chinese Academy of Sciences Yuquan Road 19# Sijingshang Block Beijing100049 China

About 3196 EA-type binaries (EAs) were observed by LAMOST by June 16, 2017 and their spectral types were derived. Meanwhile stellar atmospheric parameters of 2020 EAs were determined. In the paper, those EAs are catalogued and their physical properties and evolutionary states are investigated. The period distribution of EAs suggests that the period limit of tidal locking for the close binaries is about 6 days. It is found that the metallicity of EAs is higher than that of EWs indicating that EAs are generally younger than EWs and they are the progenitors of EWs. The metallicities of long-period EWs (0.4 Copyright © 2017, The Authors. All rights reserved.

关键词： Astrophysics

The bright star survey telescope for the planetary transit survey in Antarctica

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Science Bulletin 2016年第5期61卷 383-390页

作者： Qiguo Tian Peng Jiang Fujia Du Jian Wang Zhengyang Li Xiaoyan Li Zhiyong Zhang Haiping Lu Xiangyan Yuan Huigen Liu Hui Zhang Luming Sun Liang Chang Jianguo Wang Shaohua Zhang Tuo Ji Xiheng Shi Jie Chen Guangyu Zhang Minghao Jia Jiajing Liu Junyan Zhou Xiang Pan Shucheng Dong Fengxin Jiang Hongfei Zhang Jilin Zhou Lifan Wang Hongyan Zhou Polar Research Institute of China Shanghai 200136 China School of Astronomy and Space Science Nanjing UniversityNanjing 210093 China National Astronomical Observatories/Nanjing Institute of Astronomical Optics and Technology Chinese Academy of Sciences Nanjing 210042 China State Key Laboratory of Technologies of Particle Detection and Electronics Department of Modern Physics University of Science and Technology of China Hefei 230026 China Key Laboratory of Modern Astronomy and Astrophysics(Nanjing University) Ministry of Education Nanjing 210093China Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy University of Science and Technology of China Chinese Academy of Sciences Hefei 230026 China National Astronomical Observatories/Yunnan 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 Purple Mountain Observatory Chinese Academy of ScienceNanjing 210008 China

Transiting extrasolar planets(exoplanets),especially those orbiting bright stars, are desired for study of the diversity of planetary compositions, internal structures and atmospheres beyond our solar system. Dome A at Antarctica is a promising site for planetary transit surveys,where the continuous darkness and the large clear-sky fraction in the winter months greatly enhance the detection efficiency. The Chinese Small Telescope ARray and the Antarctic Survey Telescopes are the first facilities that have been operated at Dome A for use in exoplanet surveys. To increase the sky coverage, a low-temperature-resistant wide-field robotic telescope, named the bright star survey telescope(BSST), has been developed to join the ongoing planetary transit survey in Antarctica. The BSST has an aperture size of 300 mm and is equipped with a largeframe 4K×4K CCD camera to receive starlight from a 3.°4×3.°4 field of view. The BSST was operated at Lijiang observatory in April and May 2015 for a test *** precision of 3.5 mmag was achieved for stars with V～11 mag using 75 s exposures. The transiting events of two Jupiter-size exoplanets, HAT-P-3b and HATP-12 b, were observed on May 10 and May 20, 2015,respectively.

关键词： Instrumentation Exoplanet Photometry Antarctic Site

Panchromatic evolution of three luminous red novae: Forbidden hugs in pandemic times - IV

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arXiv 2022年

作者： Pastorello, A. Valerin, G. Fraser, M. Reguitti, A. Elias-Rosa, N. Filippenko, A.V. Rojas-Bravo, C. Tartaglia, L. Reynolds, T.M. Valenti, S. Andrews, J.E. Ashall, C. Bostroem, K.A. Brink, T.G. Burke, J. Cai, Y.-Z. Cappellaro, E. Coulter, D.A. Dastidar, R. Davis, K.W. Dimitriadis, G. Fiore, A. Foley, R.J. Fugazza, D. Galbany, L. Gangopadhyay, A. Geier, S. Gutiérrez, C.P. Haislip, J. Hiramatsu, D. Holmbo, S. Howell, D.A. Hsiao, E.Y. Hung, T. Jha, S.W. Kankare, E. Karamehmetoglu, E. Kilpatrick, C.D. Kotak, R. Kouprianov, V. Kravtsov, T. Kumar, S. Li, Z.-T. Lundquist, M.J. Lundqvist, P. Matilainen, K. Mazzali, P.A. McCully, C. Misra, K. Morales-Garoffolo, A. Moran, S. Morrell, N. Newsome, M. Gonzalez, E. Padilla Pan, Y.-C. Pellegrino, C. Phillips, M.M. Pignata, G. Piro, A.L. Reichart, D.E. Rest, A. Salmaso, I. Sand, D.J. Siebert, M.R. Smartt, S.J. Smith, K.W. Srivastav, S. Stritzinger, M.D. Taggart, K. Tinyanont, S. Yan, S.-Y. Wang, L. Wang, X.-F. Williams, S.C. Wyatt, S. Zhang, T.-M. de Boer, T. Chambers, K. Gao, H. Magnier, E. INAF Osservatorio Astronomico di Padova Vicolo dell’Osservatorio 5 PadovaI-35122 Italy Universitá degli Studi di Padova Dipartimento di Fisica e Astronomia Vicolo dell’Osservatorio 2 Padova35122 Italy School of Physics O’Brien Centre for Science North University College Dublin Belfield Dublin 4 Ireland Instituto de astrofísica Facultad de Ciencias Exactas Universidad Andres Bello Fernández Concha 700 Las Condes Santiago Chile Nuncio Monsenor Sótero Sanz 100 Providencia Santiago8320000 Chile Campus UAB Carrer de Can Magrans s/n BarcelonaE-08193 Spain Department of Astronomy University of California BerkeleyCA94720-3411 United States Miller Institute for Basic Research in Science University of California BerkeleyCA94720 United States Department of Astronomy and Astrophysics University of California Santa CruzCA95064 United States Tuorla Observatory Department of Physics and Astronomy University of Turku TurkuFI-20014 Finland Niels Bohr Institute University of Copenhagen Jagtvej 128 København N2200 Denmark Department of Physics and Astronomy University of California Davis 1 Shields Avenue DavisCA95616-5270 United States Gemini Observatory 670 North A’ohoku Place HiloHI96720-2700 United States Department of Physics Virginia Tech 850 West Campus Drive BlacksburgVA24061 United States DIRAC Institute Department of Astronomy University of Washington 3910 15th Avenue NE SeattleWA98195-0002 United States Las Cumbres Observatory 6740 Cortona Dr. Suite 102 GoletaCA93117 United States Department of Physics University of California Santa BarbaraCA93106 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 Tsinghua University Beijing100084 China School of Physics Trinity College Dublin The University of Dublin Dublin 2 Ireland Fondazione Bruno Kessler TrentoI-38123 Italy

We present photometric and spectroscopic data on three extragalactic luminous red novae (LRNe): AT 2018bwo, AT 2021afy, and AT 2021blu. AT 2018bwo was discovered in NGC 45 (at about 6.8 Mpc) a few weeks after the outburst onset. During the monitoring period, the transient reached a peak luminosity of 1040 erg s−1. AT 2021afy, hosted by UGC 10043 (∼ 49.2 Mpc), showed a double-peaked light curve, with the two peaks reaching a similar luminosity of 2.1(±0.6) × 1041 erg s−1. Finally, for AT 2021blu in UGC 5829 (∼ 8.6 Mpc), the pre-outburst phase was well-monitored by several photometric surveys, and the object showed a slow luminosity rise before the outburst. The light curve of AT 2021blu was sampled with an unprecedented cadence until the object disappeared behind the Sun, and it was then recovered at late phases. The light curve of LRN AT 2021blu shows a double peak, with a prominent early maximum reaching a luminosity of 6.5 × 1040 erg s−1, which is half of that of AT 2021afy. The spectra of AT 2021afy and AT 2021blu display the expected evolution for LRNe: a blue continuum dominated by prominent Balmer lines in emission during the first peak, and a redder continuum consistent with that of a K-type star with narrow absorption metal lines during the second, broad maximum. The spectra of AT 2018bwo are markedly different, with a very red continuum dominated by broad molecular features in absorption. As these spectra closely resemble those of LRNe after the second peak, AT 2018bwo was probably discovered at the very late evolutionary stages. This would explain its fast evolution and the spectral properties compatible with that of an M-type star. From the analysis of deep frames of the LRN sites years before the outburst, and considerations of the light curves, the quiescent progenitor systems of the three LRNe were likely massive, with primaries ranging from about 13 M for AT 2018bwo, to 14+−41 M for AT 2021blu, and over 40 M for AT 2021afy. Copyright © 2022, The Autho

关键词： Luminance

LAMOST Views δ Scuti Pulsating Stars

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arXiv 2017年

作者： Qian, S.-B. Li, L.-J. He, J.-J. Zhang, J. Zhu, L.-Y. Han, Z.-T. P. O. Box 110 Kunming650216 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences P. O. Box 110 Kunming650216 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang Dis- trict Beijing100012 China University of Chinese Academy of Sciences Yuquan Road 19# Sijingshang Block Beijing100049 China

About 766 δ Scuti stars were observed by LAMOST by 2017 June 16. Stellar atmospheric parameters of 525 variables were determined, while spectral types were obtained for all samples. In the paper, those spectroscopic data are catalogued. We detect a group of 131 unusual and cool variable stars (UCVs) that are distinguished from the normal δ Scuti stars (NDSTs). On the H−R diagram and the log g − T diagram, the UCVs are far beyond the red edge of pulsational instability trip. Their effective temperatures are lower than 6700 K with periods in the range from 0.09 to 0.22 d. NDSTs have metallicity close to that of the Sun as expected, while UCVs are slightly metal poor than NDSTs. The two peaks on the distributions of the period and stellar atmospheric parameters are all caused by the existence of UCVs. When those UCVs are excluded, it is discovered that the effective temperature, the gravitational acceleration, and the metallicity all are correlated with the pulsating period for NDSTs and their physical properties and evolutionary states are discussed. Detection of those UCVs indicates that about 25% of the known δ Scuti stars may be misclassified. However, if some of them are confirmed to be pulsating stars, they will be a new-type pulsator and their investigations will shed light on theoretical instability domains and on the theories of interacting between the pulsation and the convection of solar-type stars. Meanwhile, 88 δ Scuti stars are detected to be the candidates of binary or multiple systems. Copyright © 2017, The Authors. All rights reserved.

关键词： Temperature

Optical Observations of the 2002cx-like Supernova 2014ek, and Characterizations of SNe Iax

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arXiv 2018年

作者： Li, Linyi Wang, Xiaofeng Zhang, Jujia Arcavi, Iair Zhang, Tianmeng Rui, Liming Hosseinzadeh, Griffin Howell, D. Andrew McCully, Curtis Zhang, Kaicheng Valenti, Stefano Mo, Jun Li, Wenxiong Huang, Fang Xiang, Danfeng Wang, Lifan Zhou, Xu Tsinghua University Beijing100084 China 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 Las Cumbres Observatory 6740 Cortona Dr Suite 102 GoletaCA93117-5575 United States Department of Physics University of California Santa BarbaraCA93106-9530 United States Key Laboratory of Optical Astronomy National Astronomical Observatories of China Chinese Academy of Sciences Beijing100012 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing101408 China Department of Physics University of California DavisCA95616 United States Department of Astronomy Shanghai Jiao Tong University Shanghai200240 China George P. and Cynthia Woods Mitchell Institute for Fundamental Physics & Astronomy Texas A. & M. University College StationTX77843 United States Purple Mountain Observatory Chinese Academy of Sciences Nanjing210034 China

We present optical observations of supernova (SN) 2014ek discovered during the Tsinghua-NAOC Transient Survey (TNTS), which shows properties that are consistent with those of SN 2002cx-like events (dubbed as SNe Iax). The photometry indicates that it is underluminous compared to normal SNe Ia, with the absolute V-band peak magnitude being as −17.66±0.20 mag. The spectra are characterized by highly ionized Fe iii and intermediate-mass elements (IMEs). The expansion velocity of the ejecta is found to be ∼5000 km s−1 near the maximum light, only half of that measured for normal SNe Ia. The overall spectral evolution is quite similar to SN 2002cx and SN 2005hk, while the absorption features of the main IMEs seem to be relatively weaker. The 56Ni mass synthesized in the explosion is estimated to be about 0.08 M from the pseudo bolometric light curve. Based on a large sample of SNe Iax, we examined the relations between peak luminosity, ejecta velocity, decline rate, and peak V−R color but did not find noticeable correlations between these observables, in particular when a few extreme events like SN 2008ha are excluded in the analysis. For this sample, we also studied the birthplace environments and confirm that they still hold the trend of occurring preferentially in late-type spiral galaxies. Moreover, SNe Iax tend to occur in large star-forming regions of their host galaxies, more similar to SNe Ibc than SNe II, favoring that their progenitors should be associated with very young stellar populations. Copyright © 2018, The Authors. All rights reserved.

关键词： Supernovae