Interacting supernovae and supernova impostors. LSQ13zm: An outburst heralds the death of a massive star

L. Tartaglia, A. Pastorello, M. Sullivan, C. Baltay, D. Rabinowitz, P. Nugent, A. J. Drake, S. George Djorgovski, Avishay Gal-Yam, S. Fabrika, E. A. Barsukova, V. P. Goranskij, A. F. Valeev, T. Fatkhullin, S. Schulze, A. Mehner, F. E. Bauer, Stefan Taubenberger, J. Nordin, Stefano ValentiD. Andrew Howell, S. Benetti, E. Cappellaro, G. Fasano, N. Elias Rosa, M. Barbieri, D BETTONI, A. Harutyunyan, T. Kangas, E. Kankare, Jennifer C. Martin, Seppo Mattila, A. Morales Garoffolo, P. Ochner, Umaa D. Rebbapragada, G. Terreran, L. Tomasella, M. Turatto, E. Verroi, Przemek R. Wozniak

Research output: Contribution to journalArticlepeer-review

Abstract

We report photometric and spectroscopic observations of the optical transient LSQ13zm. Historical data reveal the presence of an eruptive episode (that we label as '2013a') followed by a much brighter outburst ('2013b') three weeks later, that we argue to be the genuine supernova explosion. This sequence of events closely resemble those observed for SN 2010mc and (in 2012) SN 2009ip. The absolute magnitude reached by LSQ13zm during 2013a (MR = -14.87 ± 0.25mag) is comparable with those of supernova impostors, while that of the 2013b event (MR = -18.46 ± 0.21mag) is consistent with those of interacting supernovae. Our spectra reveal the presence of a dense and structured circumstellar medium, probably produced through numerous pre-supernova mass-loss events. In addition, we find evidence for high-velocity ejecta, with a fraction of gas expelled at more than 20 000km s-1. The spectra of LSQ13zm show remarkable similarity with those of well-studied core-collapse supernovae. From the analysis of the available photometric and spectroscopic data, we conclude that we first observed the last event of an eruptive sequence from a massive star, likely a Luminous Blue Variable, which a short time later exploded as a core-collapse supernova. The detailed analysis of archival images suggest that the host galaxy is a star-forming Blue Dwarf Compact Galaxy.

Original languageEnglish
Pages (from-to)1039-1059
Number of pages21
JournalMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Volume459
Issue number1
Early online date23 Mar 2016
DOIs
StatePublished - 11 Jun 2016

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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