X-ray detection of SN 2013df
ATel #5150; K. L. Li and A. K.H. Kong (National Tsing Hua University, Taiwan)
on 20 Jun 2013; 10:37 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Albert Kong (firstname.lastname@example.org)
Subjects: X-ray, Supernovae, Transient
Referred to by ATel #: 8452
Following the report of a progenitor search of the Type IIb supernova 2013df (CBET #3557), a series of Swift ToO observations have been triggered since 2013 June 13 (5.5 days after the discovery). Eight observations have been taken till 2013 June 19. From the combined 14.1 ks X-Ray Telescope (XRT) observation, a hard X-ray source is seen at RA, Dec (J2000)=12h26m29.52s, +31d13m37.5s (186.6230, 31.2271) with an uncertainty of 3.8 arcsec (radius, 90% confidence), which is just 2.1 arcsec offset from the SN position (ATel #5139). There is no significant X-ray source detected at the same position in the 1.7 ks Chandra observation taken in 2000 (ObsId: 1639; PI: Garmire).
The average X-ray spectrum can be described by an absorbed power law with a photon index of 1.51 (+0.23, -0.19) and a column density of N(H)=6e20 cm^-2 obtained from the Leiden/Argentine/Bonn (LAB) map (z=0.002395 is assumed). The inferred average luminosity (absorption corrected) is about 7e39erg/s (0.3-10 keV), which is similar to previous X-ray detected SNe (see Immler & Lewin (2003)). The hard X-ray spectrum also suggests that the X-ray emissions at the SN position are very unlikely the diffuse emission of the host galaxy NGC 4414. From the X-ray lightcurve, the emission decayed gradually within the first 4e5 seconds since the trigger and showed a strong variation in the later observations.
More multi-wavelength follow-up observations are strongly encouraged.