X-ray emission of the Type Ib supernova iPTF13bvn
ATel #5210; A. K.H. Kong, K. L. Li (NTHU), E. Ofek (WIS)
on 17 Jul 2013; 07:38 UT
Credential Certification: Albert Kong (akong@phys.nthu.edu.tw)
Subjects: X-ray, Supernovae
We here report a possible detection of X-ray emission from the supernova iPTF13bvn (ATel #5137). A series of Swift ToO observations have been performed since 2013 June 17. From June 17 to July 13, there are 9 observations with a total exposure of 31.5 ks. From the combined X-Ray Telescope (XRT) image, there is an excess of X-ray photons at the supernova position. In the 0.3-10 keV band, we searched a 9 arcsec radius circular region centered at the supernova position and detected 8 photons. The average background based on a source free region is 1.18 counts and by assuming a binomial distribution, the chance probability of the occurrence of 8 or more counts is about 0.002%. At a distance of the host galaxy NGC 5806 (d=23.9 Mpc), the 0.3-10 keV unabsorbed luminosity based on the background subtracted counts is about 1e39 erg/s by assuming an absorbed power-law with a photon index of 2. The supernova flux was corrected for aperture looses (factor of ~2; Moretti et al. 2004). We also reduced a deep Swift/XRT image with an exposure of 22.5 ks taken before the supernova explosion. Only 1 count was detected at the supernova position which is consistent with noise. It is worth noting that the supernova is about 35 arcsec from the nucleus of the host galaxy NGC 5806. The X-ray emission from the AGN is clearly detected before and after the supernova explosion and their fluxes are consistent with each others.
