GCN Circular 5496
GRB 060901: Swift/XRT Refined Analysis J. Racusin (PSU) reports on behalf of the Swift XRT team: We have analyzed the first 4 orbits of Swift XRT observations of GRB 060901 (Mereghetti et al., GCN Circ. 5491), with a total exposure of 3 ks. The refined position is: RA(J2000): 19:08:37.93 Dec(J2000): -6:38:08.1 with an estimated uncertainty of 4.3 arcseconds (90% containment). This position is 0.7 arcseconds from the preliminary XRT position given in GCN Circ. 5494 (Racusin et al.) and 14.5 arcseconds from the INTEGRAL position given in GCN Circ. 5491 (Mereghetti et al.). The 0.2-10 keV light curve in Photon Counting (PC) mode starts ~14 ks after the burst. The X-ray afterglow is faint, initially 0.05 counts/s, decaying with a slope of -1.7 +/- 0.7. The preliminary spectral fit to the PC data gives a spectral power law photon index of 2.1 +/- 0.6 in the [0.3-10] keV band, assuming Galactic absorption (2.34e21cm^-2). The average (in the time range 14 - 30 ks from trigger) estimated unabsorbed 0.3-10 keV flux was ~2.6e-12 erg cm^-2 s^-1. The XRT count rate extrapolated to T+24 hr is estimated to be ~0.003 counts/s, corresponding to an unabsorbed 0.3-10 keV flux of about 4.4e-13 erg cm^-2 s^-1. This circular is an official product of the Swift XRT Team.