Signatures of an eruptive phase before the explosion of the peculiar core-collapse SN 2013gc

Abstract

We present photometric and spectroscopic analysis of the peculiar core-collapse SN 2013gc, spanning seven years of observations. The light curve shows an early maximum followed by a fast decline and a phase of almost constant luminosity. At +200 days from maximum, a brightening of 1 mag is observed in all bands, followed by a steep linear luminosity decline after +300 d. In archival images taken between 1.5 and 2.5 years before the explosion, a weak source is visible at the supernova location, with mag$\approx$20. The early supernova spectra show Balmer lines, with a narrow ($\sim$560 km s${}^{-1}$) P-Cygni absorption superimposed on a broad ($\sim$3400 km s${}^{-1}$) component, typical of type IIn events. Through a comparison of colour curves, absolute light curves and spectra of SN 2013gc with a sample of supernovae IIn, we conclude that SN 2013gc is a member of the so-called type IId subgroup. The complex profile of the H$\alpha$ line suggests a composite circumstellar medium geometry, with a combination of lower velocity, spherically symmetric gas and a more rapidly expanding bilobed feature. This circumstellar medium distribution has been likely formed through major mass-loss events, that we directly observed from 3 years before the explosion. The modest luminosity ($M_I\sim -16.5$ near maximum) of SN 2013gc at all phases, the very small amount of ejected ${}^{56}$Ni (of the order of $10^{-3}$ M${}_{\odot }$), the major pre-supernova stellar activity and the lack of prominent [O I] lines in late-time spectra support a fall-back core-collapse scenario for the massive progenitor of SN~2013gc.

arXiv comment20 pages, 11 figures, 8 tables, accepted by MNRAS

References in corpus (19)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• Pulsational pair instability as an explanation for the most luminous supernovae
• The diversity of Type II supernova versus the similarity in their progenitors
• The Unprecedented 2012 Outburst of SN 2009ip: A Luminous Blue Variable Becomes a True Supernova
• Low Luminosity Type II Supernovae: Spectroscopic and Photometric Evolution
• Groups of Galaxies in the Two Micron All-Sky Redshift Survey
• A panchromatic view of the restless SN2009ip reveals the explosive ejection of a massive star envelope
• A low energy core-collapse supernova without a hydrogen envelope
• Underluminous Type II Plateau Supernovae: II. Pointing towards moderate mass precursors
• SN 2009ip and SN 2010mc: Core-collapse Type IIn supernovae arising from blue supergiants
• Fallback Supernovae: A Possible Origin of Peculiar Supernovae with Extremely Low Explosion Energies
• Comparison of progenitor mass estimates for the type IIP SN 2012A
• A Revised Historical Light Curve of Eta Carinae and the Timing of Close Periastron Encounters
• Supernovae 2016bdu and 2005gl, and their link with SN 2009ip-like transients: another piece of the puzzle
• Endurance of SN 2005ip after a decade: X-rays, radio, and H-alpha like SN 1988Z require long-lived pre-supernova mass loss
• Interacting supernovae and supernova impostors. LSQ13zm: an outburst heralds the death of a massive star
• Supernova 1996L: evidence of a strong wind episode before the explosion
• The spectacular evolution of Supernova 1996al over 15 years: a low energy explosion of a stripped massive star in a highly structured environment
• SNhunt151: an explosive event inside a dense cocoon

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