Swift Observations of X-ray supernovae

ABSTRACT WepresentaresultofX-raysupernovae(SNe)surveyusingtheSwift satellitepublicarchive.An automatic searching programwas designed to search X-ray SNe amongall of the Swift archival observations between November 2004 and February 2011.Using the C++ program, 24 X-ray detectable supernovae have been found in thearchiveand3ofthemwerenewly-discoveredinX-rayswhichareSN1986L,SN2003lx,and SN 2007od. In addition, SN 2003lx is a Type Ia supernova which may be thesecond X-ray detectable Type Ia after SN 2005ke (Immleretal. 2006). Calibrateddata of luminous type Ib/c supernovae was consistent to the X-ray emission modeldonebyChevalierF Chevalier & Fransson 2006). According to the circum-stellar interaction model by Chevalier & Fransson (1994),cooling shell and forward/reverse shocks pair are formed asthe ejecta collides with the CSM. In most cases, the forwardshocks heat up the CSM to emit hard X-ray (& 10 keV)while the reverse shocks interact with the ejecta to emit softX-ray (. 5 keV). In the early time, the X-ray opaque cooldense shell between the shocks blocks the soft X-ray fromthe reverse shocked region. After several days or weeks, theexpanding cool shell becomes optically thin which allowsthe pass through of the soft X-ray. Since there is a rela-tively high density in the reverse shocked region, soft X-rayis strong and therefore dominates the entire X-ray emission.One of the oldest X-ray supernova detected was SN 1970Gby a Chandra deep image of M101 in 2005, 35 years afterthe explosion (Tru¨mper 2008). The luminosity of this SNwas∼ 10