The nearby Type Ibn supernova 2015G: Signatures of asymmetry and progenitor constraints

Isaac Shivvers, Wei Kang Zheng, Schuyler D. Van Dyk, Jon Mauerhan, Alexei V. Filippenko, Nathan Smith, Ryan J. Foley, Paolo Mazzali, Atish Kamble, Charles D. Kilpatrick, Raffaella Margutti, Heechan Yuk, Melissa L. Graham, Patrick L. Kelly, Jennifer Andrews, Thomas Matheson, W. Michael Wood-Vasey, Kara A. Ponder, Peter J. Brown, Roger ChevalierDan Milisavljevic, Maria Drout, Jerod Parrent, Alicia Soderberg, Chris Ashall, Andrzej Piascik, Simon Prentice

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


We present the results of an extensive observational campaign on the nearby Type Ibn SN 2015G, including data from radio through ultravioletwavelengths. SN2015Gwas asymmetric, showing late-time nebular lines redshifted by ~1000 km s-1. It shared many features with the prototypical SN Ibn 2006jc, including extremely strong He I emission lines and a late-time blue pseudo-continuum. The young SN 2015G showed narrow P-Cygni profiles of He I, but never in its evolution did it showany signature of hydrogen - arguing for a dense, ionized and hydrogenfree circumstellar medium moving outward with a velocity of ~1000 km s-1 and created by relatively recent mass-loss from the progenitor star. Ultraviolet through infrared observations show that the fading SN 2015G (which was probably discovered some 20 d post-peak) had a spectral energy distribution that was well described by a simple, single-component blackbody. Archival HST images provide upper limits on the luminosity of SN 2015G's progenitor, while non-detections of any luminous radio afterglow and optical non-detections of outbursts over the past two decades provide constraints upon its mass-loss history.

Original languageEnglish (US)
Pages (from-to)4381-4397
Number of pages17
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - 2017


  • Stars: mass-loss
  • Supernovae: individual: (SN 2015G)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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