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arXiv 2017年

作者： Xiao, Zhou Shengbang, Qian Binghe, Huang Hao, Li Jia, Zhang Yunnan Observatories Chinese Academy of Sciences PO Box 110 Kunming650216 China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences PO Box 110 Kunming650216 China Graduate University of the Chinese Academy of Sciences Yuquan Road 19 Sijingshang Block Beijing100049 China

Multi-color (B V Rc Ic) CCD photometric light curves of the contact binary V502 Oph are analyzed using the Wilson-Devinney (W-D) program. The solutions reveal that V502 Oph is a W-subtype contact (f = 35.3%) binary system. The temperature difference between its two components is 240K and the more massive star has a lower surface temperature. A cool spot is added in our model to account for the light curves' asymmetry (O'Connell effect) and third light is detected for the first time in the light curves' modeling. Combining the orbital inclination (i = 76.4◦) with the published mass function of V502 Oph, the absolute physical parameters of the two components are determined, which are M1 = 0.46(±0.02)M☉, M2 = 1.37(±0.02)M☉, R1 = 0.94(±0.01)R☉, R2 = 1.51(±0.01)R☉, L1 = 1.13(±0.02)L☉ and L2 = 2.49(±0.03)L☉. The formation and evolutionary status of V502 Oph are discussed. All photoelectric and CCD times of light minimum about V502 Oph are gathered and its orbital period variations are analyzed. The results show that the orbital period of V502 Oph is decreasing continuously at a rate of dP/dt = −1.69 × 10−7day · year−1, which corresponds to a conservative mass transfer rate of dMdt2 = −3.01 × 10−8M☉/year. The light-travel time effect (LTTE) is due to the presence of a close-in tertiary component with a period of P3 = 18.7 years and an amplitute of 0.00402days. V502 Oph is an ideal target to test the formation and evolution theories of binary and multiple systems in which the light curves, O − C curve and spectroscopic observations are comprehensively researched. Copyright © 2017, The Authors. All rights reserved.

关键词： Travel time

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A study in scarlet - II. Spectroscopic properties of a sample of Intermediate Luminosity Red Transients

arXiv

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arXiv 2024年

作者： Valerin, G. Pastorello, A. Mason, E. Reguitti, A. Benetti, S. Cai, Y.-Z. Chen, T.-W. Eappachen, D. Elias-Rosa, N. Fraser, M. Gangopadhyay, A. Hsiao, E.Y. Howell, D.A. Inserra, C. Izzo, L. Jencson, J. Kankare, E. Kotak, R. Lundqvist, P. Mazzali, P.A. Misra, K. Pignata, G. Prentice, S.J. Sand, D.J. Smartt, S.J. Stritzinger, M.D. Tartaglia, L. Valenti, S. Anderson, J.P. Andrews, J.E. Amaro, R.C. Barbarino, C. Brennan, S. Bufano, F. Callis, E. Cappellaro, E. Dastidar, R. Valle, M. Della Fiore, A. Fulton, M.D. Galbany, L. Gromadzki, M. Heikkilä, T. Hiramatsu, D. Karamehmetoglu, E. Kuncarayakti, H. Leloudas, G. Limongi, M. Lundquist, M. Müller-Bravo, T.E. Nicholl, M. Ochner, P. Gonzalez, E. Padilla Paraskeva, E. Pellegrino, C. Rau, A. Reichart, D.E. Reynolds, T.M. Roy, R. Salmaso, I. Shahbandeh, M. Singh, M. Sollerman, J. Turatto, M. Tomasella, L. Wyatt, S. Young, D.R. INAF – Osservatorio Astronomico di Padova Vicolo dell’Osservatorio 5 PadovaI-35122 Italy INAF – OATS Via G.B. Tiepolo 11 Trieste34143 Italy INAF – Osservatorio Astronomico di Brera Via E. Bianchi 46 LC Merate23807 Italy Yunnan Observatories Chinese Academy of Sciences Kunming650216 China International Centre of Supernovae Yunnan Key Laboratory Kunming650216 China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650216 China Graduate Institute of Astronomy National Central University 300 Jhongda Road Jhongli32001 Taiwan SRON Netherlands Institute for Space Research Niels Bohrweg 4 Leiden2333 CA Netherlands Department of Astrophysics IMAPP Radboud University Nijmegen P.O. Box 9010 Nijmegen6500 GL Netherlands Campus UAB Carrer de Can Magrans s/n BarcelonaE-08193 Spain School of Physics O’Brien Centre for Science North University College Dublin BelfieldDublin 4 Ireland The Oskar Klein Centre Department of Astronomy Stockholm University AlbaNova StockholmSE-10691 Sweden Hiroshima Astrophysical Science Center Hiroshima University Japan Department of Physics Florida State University 77 Chieftan Way TallahasseeFL32306 United States Las Cumbres Observatory 6740 Cortona Dr. Suite 102 GoletaCA93117 United States Department of Physics University of California Santa BarbaraCA93106 United States Cardiff Hub for Astrophysics Research and Technology School of Physics & Astronomy Cardiff University Queens Buildings The Parade CardiffCF24 3AA United Kingdom INAF Osservatorio Astronomico di Capodimonte Salita Moiariello 16 NapoliI-80131 Italy DARK Niels Bohr Institute University of Copenhagen Jagtvej 128 Copenhagen2200 Denmark Caltech/IPAC Mailcode 100-22 PasadenaCA91125 United States Tuorla Observatory Department of Physics and Astronomy University of Turku Turku20014 Finland Department of Astronomy AlbaNova University Center Stockholm University StockholmSE-10691 Swede

Aims. We investigate the spectroscopic characteristics of Intermediate Luminosity Red Transients (ILRTs), a class of elusive objects with peak luminosity between that of classical novae and standard supernovae. Our goal is to provide a stepping stone in the path to unveil the physical origin of such events, thanks to the analysis of the datasets collected. Methods. We present the extensive optical and near-infrared (NIR) spectroscopic monitoring of four ILRTs, namely NGC 300 2008OT-1, AT 2019abn, AT 2019ahd and AT 2019udc. First we focus on the evolution of the most prominent spectral features observed in the low resolution spectra, then we discuss more in detail the high resolution spectrum collected for NGC 300 2008OT-1 with the Very Large Telescope equipped with UVES. Finally we analyse late time spectra of NGC 300 2008OT-1 and AT 2019ahd through comparisons with both synthetic and observed spectra. Results. Balmer and Ca lines dominate the optical spectra, revealing the presence of slowly moving circumstellar medium (CSM) around the objects. The line luminosity of Hα, Hβ and Ca II NIR triplet presents a double peaked evolution with time, possibly indicative of interaction between fast ejecta and the slow CSM. The high resolution spectrum of NGC 300 2008OT-1 reveals a complex circumstellar environment, with the transient being surrounded by a slow (∼30 km s−1) progenitor wind. At late epochs, optical spectra of NGC 300 2008OT-1 and AT 2019ahd show broad (∼2500 km s−1) emission features at ∼6170Å and ∼7000Å which are unprecedented for ILRTs. We find that these lines originate most likely from the blending of several narrow lines, possibly of iron-peak elements. © 2024, CC BY.

关键词： Infrared devices

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Close binary evolution. III. impact of tides, wind magnetic braking, and internal angular momentum transport

arXiv

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arXiv 2017年

作者： Song, H.F. Meynet, G. Maeder, A. Ekström, S. Eggenberger, P. Georgy, C. Qin, Y. Fragos, T. Soerensen, M. Barblan, F. Wade, G.A. College of Physics Guizhou University Guiyang CityGuizhou Province550025 China Geneva Observatory Geneva University SauvernyCH-1290 Switzerland Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming650011 Guangxi Key Laboratory for Relativistic Astrophysics Department of Physics Guangxi University Nanning530004 China Department of Physics Royal Military College of Canada Ontario Canada

Context. Massive stars with solar metallicity lose important amounts of rotational angular momentum through their winds. When a magnetic field is present at the surface of a star, efficient angular momentum losses can still be achieved even when the mass-loss rate is very modest, at lower metallicities, or for lower-initial-mass stars. In a close binary system, the effect of wind magnetic braking also interacts with the influence of tides, resulting in a complex evolution of rotation. Aims. We study the interactions between the process of wind magnetic braking and tides in close binary systems. Methods. We discuss the evolution of a 10 M☉ star in a close binary system with a 7 M☉ companion using the Geneva stellar evolution code. The initial orbital period is 1.2 days. The 10 M☉ star has a surface magnetic field of 1 kG. Various initial rotations are considered. We use two different approaches for the internal angular momentum transport. In one of them, angular momentum is transported by shear and meridional currents. In the other, a strong internal magnetic field imposes nearly perfect solid-body rotation. The evolution of the primary is computed until the first mass-transfer episode occurs. The cases of different values for the magnetic fields and for various orbital periods and mass ratios are briefly discussed. Results. We show that, independently of the initial rotation rate of the primary and the efficiency of the internal angular momentum transport, the surface rotation of the primary will converge, in a time that is short with respect to the main-sequence lifetime, towards a slowly evolving velocity that is different from the synchronization velocity. This "equilibrium angular velocity" is always inferior to the angular orbital velocity. In a given close binary system at this equilibrium stage, the difference between the spin and the orbital angular velocities becomes larger when the mass losses and/or the surface magnetic field increase. The treatment of th

关键词： Angular momentum

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Using deep Residual Networks to search for galaxy-Lyα emitter lens candidates based on spectroscopic-selection

arXiv

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arXiv 2018年

作者： Li, Rui Shu, Yiping Su, Jianlin Feng, Haicheng Zhang, Guobao Wang, Jiancheng Liu, Hongtao Yunnan Observatories Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 University of Chinese Academy of Sciences Beijing100049 China Center for Astronomical Mega-Science Chinese Academy of Sciences 20A Datun Road Chaoyang District Beijing100012 Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences 396 Yangfangwang Guandu District Kunming650216 Purple Mountain Observatory Chinese Academy of Sciences 2 West Beijing Road Nanjing Jiangsu210008 China Institute of Astronomy University of Cambridge Madingley Road CambridgeCB3 0HA United Kingdom School of Mathematics Sun Yat-sen University Guangzhou China

More than one hundred galaxy-scale strong gravitational lens systems have been found by searching for the emission lines coming from galaxies with redshifts higher than the lens galaxies. Based on this spectroscopic-selection method, we introduce the deep Residual Networks (ResNet, a kind of deep Convolutional Neural Networks) to search for the galaxy-Lyα emitter (LAE) lens candidates by recognizing the Lyα emission lines coming from high redshift galaxies (2 Copyright © 2018, The Authors. All rights reserved.

关键词： Galaxies

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New photometric investigation of the low-mass-ratio contact binary star V1853 Orionis

arXiv

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arXiv 2018年

作者： He, Jia-Jia Qian, Sheng-Bang Soonthornthum, B. Aungwerojwit, A. Liu, Niang-Ping Sarotsakulchai, 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 Beijing100012 China University of Chinese Academy of Sciences Yuquan Road 19# Sijingshang Block Beijing100049 China National Astronomical Research Institute of Thailand 191 Siriphanich Bidg. 2nd Fl. Huay Kaew Rd. Suthep District Muang Chiang Mai50200 Thailand Department of Physics Faculty of Science Naresuan University Phitsanulok65000 Thailand

Four-color charge-coupled device (CCD) light curves in B, V, Rc and Ic bands of the total-eclipsing binary system, V1853 Ori, are presented. By comparing our light curves with those published by previous investigators, it is detected that the O’Connell effect on the light curves is disappeared. By analyzing those multi-color light curves with the Wilson-Devinney code (W-D code), it is discovered that V1853 Ori is an A-type intermediate-contact binary with a degree of contact factor of f = 33.3%(3.7%) and a mass ratio of q = 0.1896(0.0013). Combining our 10 new determined times of light minima together with the others published in the literature, the period changes of the system is investigated. We found that the general trend of the observed-calculated (O − C) curve shows a downward parabolic variation that corresponds to a long-term decrease in the orbital period with a rate of dP/dt = −1.96(0.46) × 10−7 d yr−1. The long-term period decrease could be explained by mass transfer from the more-massive component to the less-massive one. By combining our photometric solutions with the Gaia DR 2 data, absolute parameters were derived as M1 = 1.20 M☉, M2 = 0.23 M☉, R1 = 1.36 R☉, and R2 = 0.66 R☉. The long-term period decrease and the intermediate-contact configuration suggest that V1853 Ori will evolve into a high fill-out overcontact binary. Copyright © 2018, The Authors. All rights reserved.

关键词： Photometry

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Strong Carbon Features and a Red Early Color in the Underluminous Type Ia SN 2022xkq

arXiv

引用

arXiv 2023年

作者： Pearson, Jeniveve Sand, David J. Lundqvist, Peter Galbany, Lluís Andrews, Jennifer E. Bostroem, K. Azalee Dong, Yize Hoang, Emily Hosseinzadeh, Griffin Janzen, Daryl Jencson, Jacob E. Lundquist, Michael J. Mehta, Darshana Retamal, Nicolás Meza Shrestha, Manisha Valenti, Stefano Wyatt, Samuel Anderson, Joseph P. Ashall, Chris Auchettl, Katie Baron, Eddie Blondin, Stéphane Burns, Christopher R. Cai, Yongzhi Chen, Ting-Wan Chomiuk, Laura Coulter, David A. Cross, Dane Davis, Kyle W. de Jaeger, Thomas DerKacy, James M. Desai, Dhvanil D. Dimitriadis, Georgios Do, Aaron Farah, Joseph R. Foley, Ryan J. Gromadzki, Mariusz Gutiérrez, Claudia P. Haislip, Joshua González Hernández, Jonay I. Hinkle, Jason T. Hoogendam, Willem B. Howell, D. Andrew Hoeflich, Peter Hsiao, Eric Huber, Mark E. Jha, Saurabh W. Palau, Cristina Jiménez Kilpatrick, Charles D. Kouprianov, Vladimir Kumar, Sahana Kwok, Lindsey A. Larison, Conor LeBaron, Natalie Le Saux, Xavier Lu, Jing McCully, Curtis Evans, Tycho Mera Milne, Peter Modjaz, Maryam Morrell, Nidia Müller-Bravo, Tomás E. Newsome, Megan Nicholl, Matt Gonzalez, Estefania Padilla Payne, Anna V. Pellegrino, Craig Phan, Kim Pineda-García, Jonathan Piro, Anthony L. Piscarreta, Lara Polin, Abigail Reichart, Daniel E. Rojas-Bravo, César Ryder, Stuart D. Salmaso, Irene Schwab, Michaela Shahbandeh, Melissa Shappee, Benjamin J. Siebert, Matthew R. Smith, Nathan Strader, Jay Taggart, Kirsty Terreran, Giacomo Tinyanont, Samaporn Tucker, M.A. Valerin, Giorgio Young, D.R. Steward Observatory University of Arizona 933 North Cherry Avenue TucsonAZ85721-0065 United States Oskar Klein Centre Department of Astronomy Stockholm University Albanova University Centre StockholmSE-106 91 Sweden Campus UAB Carrer de Can Magrans s/n BarcelonaE-08193 Spain Institut d’Estudis Espacials de Catalunya Gran Capità 2-4 Edifici Nexus Desp. 201 BarcelonaE-08034 Spain Gemini Observatory 670 North A‘ohoku Place HiloHI96720-2700 United States Department of Physics and Astronomy University of California Davis 1 Shields Avenue DavisCA95616-5270 United States Department of Physics & Engineering Physics University of Saskatchewan 116 Science Place SaskatoonSKS7N 5E2 Canada Department of Physics and Astronomy The Johns Hopkins University 3400 North Charles Street BaltimoreMD21218 United States W. M. Keck Observatory 65-1120 Māmalahoa Highway KamuelaHI96743-8431 United States Department of Astronomy University of Washington 3910 15th Avenue NE SeattleWA98195-0002 United States European Southern Observatory Alonso de Córdova 3107 Casilla 19 Santiago Chile Millennium Institute of Astrophysics MAS Nuncio Monsenor Sotero Sanz 100 Off. 104 Providencia Santiago Chile Department of Physics Virginia Tech 850 West Campus Drive BlacksburgVA24061 United States School of Physics The University of Melbourne ParkvilleVIC3010 Australia Department of Astronomy and Astrophysics University of California Santa CruzCA95064-1077 United States Planetary Science Institute 1700 East Fort Lowell Road Suite 106 TucsonAZ85719-2395 United States Hamburger Sternwarte Gojenbergsweg 112 Hamburg21029 Germany Homer L. Dodge Department of Physics and Astronomy University of Oklahoma 440 W. Brooks NormanOK73019-2061 United States Aix-Marseille Univ CNRS CNES LAM Marseille13388 France Observatories of the Carnegie Institute for Science 813 Santa Barbara Street PasadenaCA91101-1232 United States Yunnan Observatories Chinese Academy of

We present optical, infrared, ultraviolet, and radio observations of SN 2022xkq, an underluminous fast-declining type Ia supernova (SN Ia) in NGC 1784 (D ≈ 31 Mpc), from Copyright © 2023, The Authors. All rights... 详细信息

关键词： Explosions

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Contribution of primordial binary evolution to the two blue-straggler sequences in globular cluster M30

arXiv

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arXiv 2017年

作者： Jiang, Dengkai Chen, Xuefei Li, Lifang Han, Zhanwen 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 Kunming650011 China

Two blue-straggler sequences discovered in globular cluster M30 provide a strong constraint on the formation mechanisms of blue stragglers. We study the formation of the blue-straggler binaries through binary evolution, and find that binary evolution can contribute to the blue stragglers in both of the sequences. Whether a blue straggler is located in the blue sequence or red sequence depends on the contribution of the mass donor to the total luminosity of the binary, which is generally observed as a single star in globular clusters. The blue stragglers in the blue sequence have a cool white-dwarf companion, while the majority (∼ 60%) of the objects in the red sequence are the binaries that are still experiencing mass transfer, but there are also some objects that the donors have just finished the mass transfer (the stripped-core stars, ∼ 10%) or the blue stragglers (the accretors) have evolved away from the blue sequence (∼ 30%). Meanwhile, W UMa contact binaries found in both sequences may be explained by various mass ratios, that is, W UMa contact binaries in the red sequence have two components with comparable masses (e.g. mass ratio q ∼ 0.3-1.0), while those in the blue sequence have low mass ratio (e.g. q Copyright © 2017, The Authors. All rights reserved.

关键词： Mass transfer

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Insight-Hxmt Observations of The New Black Hole Candidate Maxi J1535-571: Timing Analysis

arXiv

引用

arXiv 2018年

作者： Huang, Y. Qu, J.L. Zhang, S.N. Bu, Q.C. Chen, Y.P. Tao, L. Zhang, S. Lu, F.J. Li, T.P. Song, L.M. Xu, Y.P. Cao, X.L. Chen, Y. Liu, C.Z. Chang, H.-K. Yu, W.F. Weng, S.S. Hou, X. Kong, A.K.H. Xie, F.G. Zhang, G.B. Zhou, J.F. Chang, Z. Chen, G. Chen, L. Chen, T.X. Chen, Y.B. Cui, W. Cui, W.W. Deng, J.K. Dong, Y.W. Du, Y.Y. Fu, M.X. Gao, G.H. Gao, H. Gao, M. Ge, M.Y. Gu, Y.D. Guan, J. Gungor, C. Guo, C.C. Han, D.W. Hu, W. Huo, J. Ji, J.F. Jia, S.M. Jiang, L.H. Jiang, W.C. Jin, J. Jin, Y.J. Li, B. Li, C.K. Li, G. Li, M.S. Li, W. Li, X. Li, X.B. Li, X.F. Li, Y.G. Li, Z.J. Li, Z.W. Liang, X.H. Liao, J.Y. Liu, G.Q. Liu, H.W. Liu, S.Z. Liu, X.J. Liu, Y. Liu, Y.N. Lu, B. Lu, X.F. Luo, T. Ma, X. Meng, B. Nang, Y. Nie, J.Y. Ou, G. Sai, N. Shang, R.C. Sun, L. Tan, Y. Tao, W. Tuo, Y.L. Wang, G.F. Wang, H.Y. Wang, J. Wang, W.S. Wang, Y.S. Wen, X.Y. Wu, B.B. Wu, M. Xiao, G.C. Xiong, S.L. Xu, H. Yan, L.L. Yang, J.W. Yang, S. Yang, Y.J. Zhang, A.M. Zhang, C.L. Zhang, C.M. Zhang, F. Zhang, H.M. Zhang, J. Zhang, Q. Zhang, T. Zhang, W. Zhang, W.C. Zhang, W.Z. Zhang, Y. Zhang, Y. Zhang, Y.F. Zhang, Y.J. Zhang, Z. Zhang, Z. Zhang, Z.L. Zhao, H.S. Zhao, J.L. Zhao, X.F. Zheng, S.J. Zhu, Y. Zhu, Y.X. Zou, C.L. Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Chinese Academy of Sciences Beijing100049 China Department of Physics Tsinghua University Beijing100084 China Department of Astronomy Beijing Normal University Beijing100088 China Department of Engineering Physics Tsinghua University Beijing100084 China Institute of Astronomy National Tsing Hua University Hsinchu30013 Taiwan Department of Physics National Tsing Hua University Hsinchu30013 Taiwan Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai200030 China Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing210023 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 Beijing100012 China

We present the X-ray timing results of the new black hole candidate (BHC) MAXI J1535-571 during its 2017 outburst from Hard X-ray Modulation Telescope (Insight-HXMT) observations taken from 2017 September 6 to 23. Following the definitions given by Belloni (2010), we find that the source exhibits state transitions from Low/Hard state (LHS) to Hard Intermediate state (HIMS) and eventually to Soft Intermediate state (SIMS). Quasi-periodic oscillations (QPOs) are found in the intermediate states, which suggest different types of QPOs. With the large effective area of Insight-HXMT at high energies, we are able to present the energy dependence of the QPO amplitude and centroid frequency up to 100 keV which is rarely explored by previous satellites. We also find that the phase lag at the type-C QPOs centroid frequency is negative (soft lags) and strongly correlated with the centroid frequency. By assuming a geometrical origin of type-C QPOs, the source is consistent with being a high inclination system. Copyright © 2018, The Authors. All rights reserved.

关键词： Stars

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The peculiar transient AT2018cow: A possible origin of A type Ibn/IIn supernova

arXiv

引用

arXiv 2021年

作者： Xiang, Danfeng Wang, Xiaofeng Lin, Weili Mo, Jun Lin, Han Burke, Jamison Hiramatsu, Daichi Hosseinzadeh, Griffin Howell, D. Andrew McCully, Curtis Valenti, Stefan Vinkó, József Wheeler, J. Craig Ehgamberdiev, Shuhrat A. Mirzaqulov, Davron Bódi, Attila Bognár, Zsófia Cseh, Borbála Hanyecz, Ottó Ignácz, Bernadett Kalup, Csilla Könyves-Tóth, Réka Kriskovics, Levente Ordasi, András Pál, András Sárneczky, Krisztián Seli, Bálint Szakáts, Róbert Arranz-Heras, T. Benavides-Palencia, R. Cejudo-Martínez, D. de la Fuente-Fernández, P. Escartín-Pérez, A. la Cuesta, F. García-De González-Carballo, J.L. González-Farfán, R. Limón-Martínez, F. Mantero, A. Naves-Nogués, R. Morales-Aimar, M. Ruíz-Ruíz, V.R. Soldán-Alfaro, F.C. Valero-Pérez, J. Violat-Bordonau, F. Zhang, Tianmeng Zhang, Jujia Li, Xue Chen, Zhihao Sai, Hanna Li, Wenxiong Tsinghua University Beijing100084 China Beijing Planetarium Beijing Academy of Sciences and Technology Beijing100044 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing210023 China Las Cumbres Observatory 6740 Cortona Drive Suite 102 GoletaCA93117-5575 United States Department of Physics University of California Santa BarbaraCA93106-9530 United States Center for Astrophysics | Harvard & Smithsonian 60 Garden Street CambridgeMA02138-1516 United States Department of Physics and Astronomy University of California 1 Shields Avenue DavisCA95616-5270 United States Konkoly Observatory Research Centre for Astronomy and Earth Sciences Konkoly-Thege M. út 15-17 Budapest1121 Hungary ELTE Eötvös Loránd University Institute of Physics Pázmany Péter sétány 1/A Budapest1117 Hungary Department of Optics & Quantum Electronics University of Szeged Dóm tér 9 Szeged6720 Hungary Department of Astronomy University of Texas at Austin AustinTX78712 United States Ulugh Beg Astronomical Institute Uzbekistan Academy of Sciences Uzbekistan Tashkent100052 Uzbekistan CSFK Lendület Near-Field Cosmology Research Group Eötvös Loránd University Institute of Physics Pázmany Péter sétány 1/A Budapest1117 Hungary Eötvös Loránd University Department of Astronomy Pázmany Péter sétány 1/A Budapest1117 Hungary Spain Obs. Las Pequeras Navas de Oro Segovia40470 Spain Obs. Posadas MPC J53 Posadas Córdoba14730 Spain Obs. El Gallinero El Berrueco Madrid28192 Spain Obs. Llanes Llanes Asturias33784 Spain Obs. Belako Mungia Vizcaya48100 Spain Obs. La Vara MPC J38 Muñas de Arriba Asturias33784 Spain Obs. Cerro del Viento MPC I84 Badajoz06010 Spain Obs. Uraniborg MPC Z55 Écija Sevilla41400 Spain Obs. Mazariegos MPC I99 Mazariegos Palencia34170 Spain Obs. Bernezzo MPC C77 Bernezzo Cuneo12010 Italy Obs. Montcabrer MPC 213 Cabrils Barcelona08348 Spain Obs. Sencelles MPC K14 Sencelles Islas Baleares07140 Spain New Mexico Skies Unit

We present our photometric and spectroscopic observations on the peculiar transient AT2018cow. The multi-band photometry covers from peak to ∼70 days and the spectroscopy ranges from 5 to ∼50 days. The rapid rise (tr.2.9 days), high luminosity (MVpeak ∼ −20.8 mag) and fast decline after peak make AT2018cow stand out of any other optical transients. While we find that its light curves show high resemblance to those of type Ibn supernovae. Moreover, the spectral energy distribution remains high temperature of ∼14,000 K after ∼15 days since discovery. The spectra are featureless in the first 10 days, while some broad emission lines due to H, He, C and O emerge later, with velocity declining from ∼ 14, 000 km s−1 to ∼3000 km s−1 at the end of our observations. Narrow and weak He I emission lines emerge in the spectra at t >20 days since discovery. These emission lines are reminiscent of the features seen in interacting supernovae like type Ibn and IIn subclasses. We fit the bolometric light curves with a model of circumstellar interaction (CSI) and radioactive decay (RD) of 56Ni and find a good fit with ejecta mass Mej ∼ 3.16 M☉, circumstellar material mass MCSM ∼ 0.04 M☉, and ejected 56Ni mass M56Ni ∼ 0.23 M☉. The CSM shell might be formed in an eruptive mass ejection of the progenitor star. Furthermore, host environment of AT2018cow implies connection of AT2018cow with massive stars. Combining observational properties and the light curve fitting results, we conclude that AT2018cow might be a peculiar interacting supernova originated from a massive star. © 2021, CC BY.

关键词： Electromagnetic wave emission

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SEARCH FOR NEW COSMIC-RAY ACCELERATION SITES WITHIN THE 4FGL CATALOG GALACTIC PLANE SOURCES

arXiv

引用

arXiv 2022年

作者： Abdollahi, S. Acero, F. Ackermann, M. Baldini, L. Ballet, J. Barbiellini, G. Bastieri, D. Bellazzini, R. Berenji, B. Berretta, A. Bissaldi, E. Blandford, R.D. Bonino, R. Bruel, P. Buson, S. Cameron, R.A. Caputo, R. Caraveo, P.A. Castro, D. Chiaro, G. Cibrario, N. Ciprini, S. Coronado-Blázquez, J. Crnogorcevic, M. Cutini, S. D'Ammando, F. De Gaetano, S. Di Lalla, N. Dirirsa, F. Di Venere, L. Domínguez, A. Fegan, S.J. Fiori, A. Fleischhack, H. Franckowiak, A. Fukazawa, Y. Fusco, P. Gammaldi, V. Gargano, F. Gasparrini, D. Giacchino, F. Giglietto, N. Giordano, F. Giroletti, M. Glanzman, T. Green, D. Grenier, I.A. Grondin, M.-H. Guiriec, S. Gustafsson, M. Harding, A.K. Hays, E. Hewitt, J.W. Horan, D. Hou, X. Jóhannesson, G. Kayanoki, T. Kerr, M. Kuss, M. Larsson, S. Latronico, L. Lemoine-Goumard, M. Li, J. Longo, F. Loparco, F. Lubrano, P. Maldera, S. Malyshev, D. Manfreda, A. Martí-Devesa, G. Mazziotta, M.N. Mereu, I. Michelson, P.F. Mirabal, N. Mitthumsiri, W. Mizuno, T. Monzani, M.E. Morselli, A. Moskalenko, I.V. Nuss, E. Omodei, N. Orienti, M. Orlando, E. Ormes, J.F. Paneque, D. Pei, Z. Persic, M. Pesce-Rollins, M. Pillera, R. Poon, H. Porter, T.A. Principe, G. Rainò, S. Rando, R. Rani, B. Razzano, M. Razzaque, S. Reimer, A. Reimer, O. Reposeur, T. Sánchez-Conde, M. Parkinson, P.M. Saz Scotton, L. Serini, D. Sgrò, C. Siskind, E.J. Spandre, G. Spinelli, P. Sueoka, K. Suson, D.J. Tajima, H. Tak, D. Thayer, J.B. Torres, D.F. Troja, E. Valverde, J. Wadiasingh, Z. Wood, K. Zaharijas, G. IRAP Université de Toulouse CNRS UPS CNES ToulouseF-31028 France Université Paris Saclay Université Paris Cité CEA CNRS AIM Gif-sur-Yvette F-91191 France Deutsches Elektronen Synchrotron DESY ZeuthenD-15738 Germany Università di Pisa Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy Istituto Nazionale di Fisica Nucleare Sezione di Trieste TriesteI-34127 Italy Dipartimento di Fisica Università di Trieste TriesteI-34127 Italy Istituto Nazionale di Fisica Nucleare Sezione di Padova PadovaI-35131 Italy Dipartimento di Fisica e Astronomia "G. Galilei" Università di Padova PadovaI-35131 Italy Center for Space Studies and Activities "G. Colombo" University of Padova Via Venezia 15 PadovaI-35131 Italy Istituto Nazionale di Fisica Nucleare Sezione di Pisa PisaI-56127 Italy California State University Los Angeles Department of Physics and Astronomy Los AngelesCA90032 United States Dipartimento di Fisica Università degli Studi di Perugia PerugiaI-06123 Italy Dipartimento di Fisica "M. Merlin" Università e del Politecnico di Bari via Amendola 173 BariI-70126 Italy Istituto Nazionale di Fisica Nucleare Sezione di Bari BariI-70126 Italy W. W. Hansen Experimental Physics Laboratory Kavli Institute for Particle Astrophysics and Cosmology Department of Physics SLAC National Accelerator Laboratory Stanford University StanfordCA94305 United States Istituto Nazionale di Fisica Nucleare Sezione di Torino TorinoI-10125 Italy Dipartimento di Fisica Università degli Studi di Torino TorinoI-10125 Italy Laboratoire Leprince-Ringuet École Polytechnique CNRS IN2P3 PalaiseauF-91128 France Institut für Theoretische Physik and Astrophysik Universität Würzburg WürzburgD-97074 Germany NASA Goddard Space Flight Center GreenbeltMD20771 United States INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano via E. Bassini 15 MilanoI-20133 Italy Harvard-Smithsonian Center for Astrophysics CambridgeMA02138 United States Is

Cosmic rays are mostly composed of protons accelerated to relativistic speeds. When those protons encounter interstellar material, they produce neutral pions which in turn decay into gamma rays. This offers a compelling way to identify the acceleration sites of protons. A characteristic hadronic spectrum, with a low-energy break around 200 MeV, was detected in the gamma-ray spectra of four Supernova Remnants (SNRs), IC 443, W44, W49B and W51C, with the Fermi Large Area Telescope. This detection provided direct evidence that cosmic-ray protons are (re-)accelerated in SNRs. Here, we present a comprehensive search for low-energy spectral breaks among 311 4FGL catalog sources located within 5◦ from the Galactic plane. Using 8 years of data from the Fermi Large Area Telescope between 50 MeV and 1 GeV, we find and present the spectral characteristics of 56 sources with a spectral break confirmed by a thorough study of systematic uncertainty. Our population of sources includes 13 SNRs for which the proton-proton interaction is enhanced by the dense target material;the high-mass γ-ray binary LS I +61 303;the colliding wind binary η Carinae;and the Cygnus star-forming region. This analysis better constrains the origin of the γ-ray emission and enlarges our view to potential new cosmic-ray acceleration sites. Copyright © 2022, The Authors. All rights reserved.

关键词： Cosmic rays

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