Title: The type Ib supernova 2010O: an explosion in a Wolf-Rayet X-ray binary? Authors: G. Nelemans, R. Voss, M.T.B. Nielsen, G. Roelofs (Version v2)
The type Ib supernova 2010O was recently discovered in the interacting starburst galaxy Arp 299. We present an analysis of two archival Chandra X-ray observations of Arp 299, taken before the explosion and show that there is a transient X-ray source at a position consistent with the supernova. Due to the diffuse emission, the background is difficult to estimate. We estimate the flux of the transient from the difference of the two X-ray images and conclude that the transient can be described by a 0.225 keV black body with a luminosity of 2.5±0.7 10^{39} erg/s for a distance of 41 Mpc. These properties put the transient in between the Galactic black hole binary XTE J1550-564 and the ultra-luminous X-ray binaries NGC 1313 X-1 and X-2. The high level of X-ray variability associated with the active starburst makes it impossible to rule out a chance alignment. If the source is associated with the supernova, it suggests SN2010O is the explosion of the second star in a Wolf-Rayet X-ray binary, such as Cyg X-3, IC 10 X-1 and NGC 300 X-1.
A magnitude 15.6 supernova, 2010O, was discovered by J. Newton and T. Puckett on the 24th January, 2010, in the galaxy NGC 3690 in the constellation Ursa Major. The supernova is located 3.7" East and 5.7" North from the center of the galaxy. As yet the type is unknown.
Position (2000): RA 11 28 33.86, Dec +58° 33' 51.6"