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


Abstract in English

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 $m_{F435W}=26.76pm0.20$, $m_{F555W}=26.60pm0.23$ and $m_{F625W} = 26.32pm0.19$ mags, although there is no detection in a contemporaneous narrow-band $mathrm{Halpha}$ 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 sources 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 $1mathrm{pc}$) 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.

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