We present the results of a 63 ks { \it Chandra} observation of the "supernova impostor" SN 2010da four months after it was first observed on 25 May 2010. We detect an X-ray source at $\sim7\sigma$ confidence coincident with the optical location of the SN 2010da outburst. Our imaging analysis has revealed a hard central point source, surrounded by soft diffuse emission extending as far as $\sim$8\asn north of the central source. The diffuse emission has a hardness ratio, 0.35-2 keV luminosity ($\sim6\times10^{ 35}$ erg s$^{ -1}$), and size ($\sim20$ pc) consistent with that of a supernova remnant, although the low number of counts prohibits detailed spectral modeling. Our best-fit spectral model for the hard central source is a black body ($kT = 1.79^{ +0.66}_{ -0.43}$ keV) with no evidence for intrinsic absorption beyond the Galactic column. We estimate the 0.3-10 keV luminosity to be 1.7$^{ +0.2}_{ -0.5}\times10^{ 37}$ erg s$^{ -1}$, a factor of $\sim$25 decrease since the initial outburst four months previously. The high X-ray luminosity and slow fading rate is not consistent with this object being a single massive star undergoing an outburst; instead, we favor the scenario where the massive star powering the SN 2010da optical transient is part of a wind-fed supergiant X-ray binary system with a compact companion powering the observed X-ray emission.
Categories: astro-ph.HE astro-ph.CO