The Late Time Optical Evolution of Twelve Core-Collapse Supernovae: Detection of Normal Stellar Winds

TL;DR

This study examines the late-time optical emission of twelve core-collapse supernovae over 41 years, revealing that most emissions are due to circumstellar medium interactions with stellar winds, and provides progenitor constraints.

Contribution

It is the first comprehensive analysis of late-time supernova evolution using optical data from the LBT, highlighting CSM interactions as the primary emission source and constraining progenitor properties.

Findings

Late-time emission observed in 9 of 11 Type II SNe.

Emission primarily explained by CSM interactions with stellar winds.

Constraints on binary companion presence and progenitor photometry provided.

Abstract

We analyze the late time evolution of 12 supernovae (SNe) occurring over the last ${\sim}$41 years, including nine Type IIP/L, two IIb, and one Ib/c, using UBVR optical data from the Large Binocular Telescope (LBT) and difference imaging. We see late time (5 to 42 years) emission from nine of the eleven Type II SNe (eight Type IIP/L, one IIb). We consider radioactive decay, circumstellar medium (CSM) interactions, pulsar/engine driven emission, dust echoes, and shock perturbed binary companions as possible sources of emission. The observed emission is most naturally explained as CSM interactions with the normal stellar winds of red supergiants with mass loss rates in the range $-7.9\lesssim \log_{10}(M_\odot\text{yr}{}^{-1}) \lesssim-4.8$. We also place constraints on the presence of any shock heated binary companion to the Type Ib/c SN 2012fh and provide progenitor photometry for the Type IIb SN 2011dh, the only one of the six SNe with pre-explosion LBT observations where the SN has faded sufficiently to allow the measurement. The results are consistent with measurements from pre-explosion Hubble Space Telescope (HST) images.