SN 2015bn: A DETAILED MULTI-WAVELENGTH VIEW of A NEARBY SUPERLUMINOUS SUPERNOVA

M. Nicholl, E. Berger, S. J. Smartt, R. Margutti, A. Kamble, K. D. Alexander, T. W. Chen, C. Inserra, I. Arcavi, P. K. Blanchard, R. Cartier, K. C. Chambers, M. J. Childress, R. Chornock, P. S. Cowperthwaite, M. Drout, H. A. Flewelling, M. Fraser, A. Gal-Yam, L. GalbanyJ. Harmanen, T. W S Holoien, G. Hosseinzadeh, D. A. Howell, M. E. Huber, A. Jerkstrand, E. Kankare, C. S. Kochanek, Z. Y. Lin, R. Lunnan, E. A. Magnier, K. Maguire, C. McCully, M. McDonald, B. D. Metzger, D. Milisavljevic, A. Mitra, T. Reynolds, J. Saario, B. J. Shappee, K. W. Smith, S. Valenti, V. A. Villar, C. Waters, D. R. Young

Research output: Contribution to journalReview articlepeer-review

68 Scopus citations

Abstract

We present observations of SN 2015bn (=PS15ae = CSS141223-113342+004332 = MLS150211-113342+004333), a Type I superluminous supernova (SLSN) at redshift z = 0.1136. As well as being one of the closest SLSNe I yet discovered, it is intrinsically brighter (MU ≈ -23.1) and in a fainter galaxy (MB ≈ -16.0) than other SLSNe at . We used this opportunity to collect the most extensive data set for any SLSN I to date, including densely sampled spectroscopy and photometry, from the UV to the NIR, spanning -50 to +250 days from optical maximum. SN 2015bn fades slowly, but exhibits surprising undulations in the light curve on a timescale of 30-50 days, especially in the UV. The spectrum shows extraordinarily slow evolution except for a rapid transformation between +7 and +20-30 days. No narrow emission lines from slow-moving material are observed at any phase. We derive physical properties including the bolometric luminosity, and find slow velocity evolution and non-monotonic temperature and radial evolution. A deep radio limit rules out a healthy off-axis gamma-ray burst, and places constraints on the pre-explosion mass loss. The data can be consistently explained by a ≳ 10 M stripped progenitor exploding with erg kinetic energy, forming a magnetar with a spin-down timescale of ∼20 days (thus avoiding a gamma-ray burst) that reheats the ejecta and drives ionization fronts. The most likely alternative scenario - interaction with ∼20 M of dense, inhomogeneous circumstellar material - can be tested with continuing radio follow-up.

Original languageEnglish (US)
Article number39
JournalAstrophysical Journal
Volume826
Issue number1
DOIs
StatePublished - Jul 20 2016

Keywords

  • supernovae: general
  • supernovae: individual (SN 2015bn)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Fingerprint Dive into the research topics of 'SN 2015bn: A DETAILED MULTI-WAVELENGTH VIEW of A NEARBY SUPERLUMINOUS SUPERNOVA'. Together they form a unique fingerprint.

Cite this