The possible detection of a binary companion to a Type Ibn supernova progenitor

TL;DR

Late-time Hubble observations of SN 2006jc reveal a faint blue source at the explosion site, providing evidence against a luminous blue variable companion and suggesting possible dust echo or stellar origin.

Contribution

This study presents the first late-time imaging of SN 2006jc's site, constraining the nature of its progenitor's companion and exploring potential dust echoes.

Findings

Faint blue source detected at SN site with specific magnitudes.

Source's spectral energy distribution consistent with a stellar-like object.

Luminous blue variable companion ruled out based on observations.

Abstract

We present late-time observations of the site of the Type Ibn supernova (SN) 2006jc acquired with the Hubble Space Telescope Advanced Camera for Surveys. A faint blue source is recovered at the SN position with brightness $m_{F435W}=26.76\pm0.20$, $m_{F555W}=26.60\pm0.23$ and $m_{F625W} = 26.32\pm0.19$ mags, although there is no detection in a contemporaneous narrow-band $\mathrm{H\alpha}$ image. The spectral energy distribution of the late-time source is well fit by a stellar-like spectrum ($\log T_{eff} > 3.7$ and $\log L / L_{\odot} > 4$) subject to only a small degree of reddening consistent with that estimated for SN~2006jc itself at early-times. The lack of further outbursts after the explosion of SN~2006jc suggests that the precursor outburst originated from the progenitor. The possibility of the source being a compact host cluster is ruled out on the basis of the source's faintness, however the possibility that the late-time source maybe an unresolved light echo originating in a shell or sphere of pre-SN dust (within a radius $1\mathrm{pc}$) is also discussed. Irrespective of the nature of the late-time source, these observations rule out a luminous blue variable as a companion to the progenitor of SN~2006jc.