TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5209 SUBJECT: GRB 060602B: Swift-XRT Refined Analysis DATE: 06/06/04 00:33:38 GMT FROM: Andy Beardmore at U Leicester A.P. Beardmore, O. Godet (U. Leicester) and T. Sakamoto (GSFC/ORAU) report on behalf of the Swift-XRT team : We have analysed the first 11.4ks of Swift XRT PC mode data from the BAT trigger GRB060602B (Schady et al., GCN 5200; trigger number 213190). We find a refined XRT position of: RA(J2000) = 17:49:31.6 Dec(J2000) = -28:08:03.2 with an estimated uncertainty of 3.7 arcsec (90% containment). This is 1.4 arcsec away from the XRT position reported in GCN 5200 and 64.2 arcsec from the refined BAT position (Palmer et al., GCN 5208). The X-ray light curve shows a small rise in intensity until T+200s, then follows a simple power-law decay with a index of 1.05 +/- 0.07. The X-ray spectrum over the same interval (T+100s to T+40ks) can be well modelled by an absorbed power-law, with a photon index of 3.1 +/- 0.6 and a column density of 5.0 +/- 1.4 E22 cm^-2. The measured galactic column density in this direction is 1.4E22 cm^-2. The observed 0.3-10keV flux is 3.2E-12 ergs cm**-2 s**-1, which corresponds to an unabsorbed flux of 5.0E-11 ergs cm**-2 s**-1. The measured spectral and temporal indices are difficult to reconcile with standard GRB afterglow models. The X-ray spectrum can also be equally well fit by an absorbed blackbody model, with a temperature of 0.90+/-0.09 keV and a column density of 2.1 +/- 0.7 E22 cm^-2. This model has an observed (unabsorbed) 0.3-10 keV flux of 2.8E-12 (4.3E-12) ergs cm**-2 s**-1. Assuming the source decays at the same rate, we predict an XRT count rate of 0.0011 count/s at T+48 hrs, which corresponds to an observed flux of 8.8E-14 ergs cm**-2 s**-1. This Circular is an official product of the Swift XRT Team.