@article{bfd9a7f1ccd3465183bb97f8c0cbadc2,
title = "ASASSN-15pz: Revealing Significant Photometric Diversity among 2009dc-like, Peculiar SNe Ia",
abstract = "We report comprehensive multi-wavelength observations of a peculiar Type Ia-like supernova ({"}SN Ia-pec{"}) ASASSN-15pz. ASASSN-15pz is a spectroscopic {"}twin{"} of SN 2009dc, a so-called {"}Super-Chandrasekhar-mass{"} SN, throughout its evolution, but it has a peak luminosity M-B,(peak) = -19.69 +/- 0.12 mag that is approximate to 0.6 mag dimmer and comparable to the SN 1991T sub-class of SNe Ia at the luminous end of the normal width-luminosity relation. The synthesized Ni-56 mass of M-56Ni = 1.13 +/- 0.14 M-circle dot is also substantially less than that found for several 2009dc-like SNe. Previous well-studied 2009dc-like SNe have generally suffered from large and uncertain amounts of host-galaxy extinction, which is negligible for ASASSN-15pz. Based on the color of ASASSN-15pz, we estimate a host extinction for SN 2009dc of E(B - V)(host) = 0.12 mag and confirm its high luminosity (M-B,(peak) [2009dc] approximate to -20.3 mag). The 2009dc-like SN population, which represents similar to 1% of SNe Ia, exhibits a range of peak luminosities, and do not fit onto the tight width-luminosity relation. Their optical light curves also show significant diversity of late-time (greater than or similar to 50 days) decline rates. The nebular-phase spectra provide powerful diagnostics to identify the 2009dc-like events as a distinct class of SNe Ia. We suggest referring to these sources using the phenomenology-based {"}2009dc-like SN Ia-pec{"} instead of {"}Super-Chandrasekhar SN Ia,{"} which is based on an uncertain theoretical interpretation.",
author = "Ping Chen and Subo Dong and Boaz Katz and Kochanek, {C. S.} and Kollmeier, {Juna A.} and K. Maguire and Phillips, {M. M.} and Prieto, {J. L.} and Shappee, {B. J.} and Stritzinger, {M. D.} and Subhash Bose and Brown, {Peter J.} and Holoien, {T. W-S} and L. Galbany and Milne, {Peter A.} and Nidia Morrell and Piro, {Anthony L.} and Stanele, {K. Z.} and Thompson, {Todd A.} and Young, {D. R.}",
note = "We thank Doron Kushnir, Erika K. Carlon, Francesco Taddia, Barry Madore, Mark Seibert, and Jeff Rich for their help. P.C., S.D., and S. B. acknowledge Project 11573003 supported by NSFC. This research uses data obtained through the Telescope Access Program (TAP), which has been funded by the National Astronomical Observatories of China, the Chinese Academy of Sciences, and the Special Fund for Astronomy from the Ministry of Finance. K.M. acknowledges support from STFC (ST/M005348/1) and from H2020 through an ERC Starting Grant (758638). CSK, K.Z.S., and T.A.T. are supported by NSF grants AST-1515876, AST-1515927, and AST-1814440. P.J.B. is supported by NASA through HST program #14144 through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Support for J.L.P. is provided in part by FONDECYT through the grant 1191038 and by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. This work is partly based on observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. The data presented here were obtained in part with ALFOSC, which is provided by the Instituto de Astrofisica de Andalucia (IAA) under a joint agreement with the University of Copenhagen and NOTSA. M.S. is supported in part by a generous grant (13261) from VILLUM FONDEN and a project grant from the Independent Research Fund Denmark. This work is based (in part) on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, under ESO programme 0101.D-0202, and as part of PESSTO (the Public ESO Spectroscopic Survey for Transient Objects Survey) ESO program 188.D-3003, 191.D-0935, 197.D-1075. We thank the Las Cumbres Observatory and its staff for its continuing support of the ASAS-SN project. ASAS-SN is supported by the Gordon and Betty Moore Foundation through grant GBMF5490 to the Ohio State University and NSF grant AST-1515927. Development of ASAS-SN has been supported by NSF grant AST-0908816, the Mt. Cuba Astronomical Foundation, the Center for Cosmology and AstroParticle Physics at the Ohio State University, the Chinese Academy of Sciences South America Center for Astronomy (CAS- SACA), the Villum Foundation, and George Skestos. This paper uses data products produced by the OIR Telescope Data Center, supported by the Smithsonian Astrophysical Observatory. UKIRT is owned by the University of Hawaii (UH) and operated by the UH Institute for Astronomy; operations are enabled through the cooperation of the East Asian Observatory. When (some of) the data reported here were acquired, UKIRT was supported by NASA and operated under an agreement among the University of Hawaii, the University of Arizona, and Lockheed Martin Advanced Technology Center; operations were enabled through the cooperation of the East Asian Observatory.",
year = "2019",
month = jul,
day = "20",
doi = "https://doi.org/10.3847/1538-4357/ab2630",
language = "الإنجليزيّة",
volume = "880",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",
}