@article{60e9a9a511254c85aeabb74757f0f011,
title = "Nebular Spectroscopy of the {"}blue Bump{"} Type Ia Supernova 2017cbv",
abstract = "We present nebular phase optical and near-infrared spectroscopy of the Type Ia supernova (SN) 2017cbv. The early light curves of SN 2017cbv showed a prominent blue bump in the U, B, and g bands lasting for ∼5 days. One interpretation of the early light curve is that the excess blue light is due to shocking of the SN ejecta against a nondegenerate companion star - a signature of the single degenerate scenario. If this is the correct interpretation, the interaction between the SN ejecta and the companion star could result in significant H (or helium) emission at late times, possibly along with other species, depending on the companion star and its orbital separation. A search for H emission in our +302 d spectrum yields a nondetection, with a L H < 8.0 × 1035 erg s-1 (given an assumed distance of D = 12.3 Mpc), which we verified by implanting simulated H emission into our data. We make a quantitative comparison to models of swept-up material stripped from a nondegenerate companion star and limit the mass of hydrogen that might remain undetected to M H < 1 × 10-4 M o. A similar analysis of helium star related lines yields a M He < 5 × 10-4 M o. Taken at face value, these results argue against a nondegenerate H- or He-rich companion in Roche lobe overflow as the progenitor of SN 2017cbv. Alternatively, there could be weaknesses in the envelope-stripping and radiative transfer models necessary to interpret the strong H and He flux limits.",
keywords = "supernovae: general, supernovae: individual (SN 2017cbv)",
author = "Sand, {D. J.} and Graham, {M. L.} and J. Boty{\'a}nszki and D. Hiramatsu and C. McCully and S. Valenti and G. Hosseinzadeh and Howell, {D. A.} and J. Burke and R. Cartier and T. Diamond and Hsiao, {E. Y.} and Jha, {S. W.} and D. Kasen and S. Kumar and Marion, {G. H.} and N. Suntzeff and L. Tartaglia and Wheeler, {J. C.} and S. Wyatt",
note = "Funding Information: This research makes use of observations from the Las Cumbres Observatory. Based on observations obtained at the Gemini Observatory under programs GS-2017B-Q-14 (PI: Howell) and GS-2017B-Q-58 (PI: Sand). Gemini is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the NSF (United States), the National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnolog{\'i}a e Innovaci{\'o}n Productiva (Argentina), and Minist{\'e}rio da Ci{\^e}ncia, Tecnologia e Inova{\c c}{\~a}o (Brazil). The data were processed using the Gemini IRAF package. We thank the queue service observers and technical support staff at Gemini Observatory for their assistance. Funding Information: This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Funding Information: Research by D.J.S. and S.W. is supported by NSF grants AST-1821987 and 1821967. The work of C.M., G.H., and D.A.H. is supported by US National Science Foundation (NSF) grant AST 1313484. E.Y.H. and S.K. acknowledge the support provided by the National Science Foundation under Grant No. AST-1613472 and by the Florida Space Grant Consortium. Publisher Copyright: {\textcopyright} 2018. The American Astronomical Society. All rights reserved.",
year = "2018",
month = aug,
day = "10",
doi = "10.3847/1538-4357/aacde8",
language = "English (US)",
volume = "863",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",
}