TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4304 SUBJECT: GRB051117B: Swift XRT refined analysis DATE: 05/11/25 16:39:23 GMT FROM: Andy Beardmore at U Leicester A.P. Beardmore, K.L. Page (U. Leicester), K. Hurley (Berkeley), M. Chester (PSU) report on behalf of the Swift XRT team. We report on further analysis of the XRT observation of GRB051117B. By fitting the XRT point spread function to 8ks of PC mode data obtained from the first observation segment, we find the following revised position: RA(J2000) = 05:40:43.0 Dec(J2000) = -19:16:26.5 with an uncertainty of 3.4 arcsec (90% containment). This includes the latest XRT boresight correction. The XRT 0.2-10keV light curve shows a simple power-law decay with a slope of 1.75 +/- 0.25 out to T+12.8ks. After this time the source was no longer detected, with a 3 sigma upper limit to the count rate of 2.7e-4 count/s in an exposure of 85ks. An absorbed power-law fit to the photon counting mode spectrum from T+149s to T+12.8ks gave a photon index 1.9 +1.1/-0.6 and a column density of (0.4 +0.7/-0.2)e22 cm**2. The Galactic column in this direction is 4.5E+20 cm**2. The unabsorbed 0.2-10keV flux was 1.4e-12 ergs cm**-2 s**-1.