English

SN 2009ip at late times - an interacting transient at +2 years

Solar and Stellar Astrophysics 2015-09-30 v1

Abstract

We present photometric and spectroscopic observations of the interacting transient SN 2009ip taken during the 2013 and 2014 observing seasons. We characterise the photometric evolution as a steady and smooth decline in all bands, with a decline rate that is slower than expected for a solely 56^{56}Co-powered supernova at late phases. No further outbursts or eruptions were seen over a two year period from 2012 December until 2014 December. SN 2009ip remains brighter than its historic minimum from pre-discovery images. Spectroscopically, SN 2009ip continues to be dominated by strong, narrow (\lesssim2000 km~s1^{-1}) emission lines of H, He, Ca, and Fe. While we make tenuous detections of [Fe~{\sc ii}] λ\lambda7155 and [O~{\sc i}] λλ\lambda\lambda6300,6364 lines at the end of 2013 June and the start of 2013 October respectively, we see no strong broad nebular emission lines that could point to a core-collapse origin. In general, the lines appear relatively symmetric, with the exception of our final spectrum in 2014 May, when we observe the appearance of a redshifted shoulder of emission at +550 km~s1^{-1}. The lines are not blue-shifted, and we see no significant near- or mid-infrared excess. From the spectroscopic and photometric evolution of SN 2009ip until 820 days after the start of the 2012a event, we still see no conclusive evidence for core-collapse, although whether any such signs could be masked by ongoing interaction is unclear.

Keywords

Cite

@article{arxiv.1502.06033,
  title  = {SN 2009ip at late times - an interacting transient at +2 years},
  author = {Morgan Fraser and Rubina Kotak and Andrea Pastorello and Anders Jerkstrand and Stephen J. Smartt and Ting-Wan Chen and Michael Childress and Gerard Gilmore and Cosimo Inserra and Erkki Kankare and Steve Margheim and Seppo Mattila and Stefano Valenti and Christopher Ashall and Stefano Benetti and Maria Teresa Botticella and Franz Erik Bauer and Heather Campbell and Nancy Elias-Rosa and Mathilde Fleury and Avishay Gal-Yam and Stephan Hachinger and D. Andrew Howell and Laurent Le Guillou and Pierre-François Léget and Antonia Morales-Garoffolo and Joe Polshaw and Susanna Spiro and Mark Sullivan and Stefan Taubenberger and Massimo Turatto and Emma S. Walker and David R. Young and Bonnie Zhang},
  journal= {arXiv preprint arXiv:1502.06033},
  year   = {2015}
}

Comments

Submitted to MNRAS