2007IAUC.8799....2R

J. Rho, California Institute of Technology, together with T. H. Jarrett and R. Chevalier, report x-ray emission from SN 2004et (cf. IAUC 8413) in the spiral galaxy NGC 6946. The x-ray detection was serendipitously found using archival Chandra X-ray Observatory data of three separate pointings, each about 29000 s in length. For the location of 2004et, a total of 202, 151, and 158 photons were detected for the observations on 2004 Oct. 22, Nov. 6, and Dec. 3, respectively. The spectrum of the first observation is best fitted by a thermal model with a temperature of 1.3 keV (lower limit 0.5 keV) and a line-of-sight absorption of 1 x 10**22 cm**-2 [upper limit 2 x 10**22 cm**-2]. The estimated extinction to the supernova, A_v = 0.41 mag (Zwitter et al. 2004, IAUC 8413), is consistent with a foreground atomic-hydrogen column density of 3 x 10**21 cm**-2, corresponding to the lower envelope of the present x-ray absorption measurements. The inferred unabsorbed luminosity (0.4-10 keV) is about 4 x 10**38 erg/s (using a distance of 5.5 Mpc), which falls into the luminosity range of known x-ray supernovae. The x-ray hardness ratio declines between the first and last epoch, consistent with a slight temperature decrease over the time period.