Early spectroscopic identification of SN 2008D

Daniele M Malesani, Johan Peter Uldall Fynbo, Jens Hjorth, Giorgos Leloudas, Jesper Sollerman, Maximilian D Stritzinger, Paul Marijn Vreeswijk, Darach J Watson, Javier Gorosabel, Michal J Michalowski, Christina C Thone, Thomas Augusteijn, David F Bersier, Pall Jakobsson, Andreas Ortmann Jaunsen, Cedric Ledoux, Andrew J Levan, Bo Milvang-Jensen, Evert Rol, Nial R TanvirKlass Wiersema, Dong Xu, Loic Albert, Matthew B Bayliss, Christa Gall, Lisbeth Fogh Grove, Benjamin P Koester, Elisabet Leitet, Tapio Pursimo, Ian Skillen

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54 Citations (Scopus)

Abstract

SN2008D was discovered while following up an unusually bright X-ray transient (XT) in the nearby spiral galaxy NGC2770. We present early optical spectra (obtained 1.75 days after the XT) which allowed the first identification of the object as a supernova (SN) at redshift z = 0.007. These spectra were acquired during the initial declining phase of the light curve, likely produced in the stellar envelope cooling after shock breakout, and rarely observed. They exhibit a rather flat spectral energy distribution with broad undulations, and a strong, W-shaped feature with minima at 3980 and 4190 (rest frame). We also present extensive spectroscopy and photometry of the SN during the subsequent photospheric phase. Unlike SNe associated with gamma-ray bursts, SN2008D displayed prominent He features and is therefore of Type Ib.
Original languageEnglish
Pages (from-to)84 - 87
Number of pages4
JournalThe Astrophysical Journal
Volume692
Issue number2
DOIs
Publication statusPublished - 2009
Externally publishedYes

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