GCN Circular 3816
D. C. Morris, D. N. Burrows, J. A. Kennea, J. L. Racusin (PSU), and N. Gehrels (GSFC) report on behalf of the Swift XRT team: We have analysed the first three orbits of data for GRB050815 (GCN 3811, Fox et al., 2005). Using xrtcentoid, the refined position is: RA(J2000) = 19h 34m 23.2s Dec(J2000) = +09d 08' 49.6" with an uncertainty of 8 arcsec. This is 5.6 arcsec from the original XRT position (GCN 3812, Morris et al., 2005). The XRT began taking data at 17:26:28UT, 69 seconds after the BAT trigger. The XRT collected data for only 123s during the first orbit before the source was occulted. The data show a faint source in the first orbit and suggest an initially shallow decay index of ~-0.2 followed by a break occuring somewhere between 192s and 3000s to a steeper decay index of ~-2.1. The spectrum is well fit (reduced chi-sq of 1.03 for 9 dof) by a power law with neutral hydrogen consistent with the galactic column density of 2.7e21: gamma=1.4 + / - 0.2 NH=2.1e21 + / - 7e20 Fixing the NH to the galactic column density also returns a good fit (reduced chi-sq of 1.00 for 10 dof): gamma=1.5 + / - 0.1 The count rate at 10000s after the trigger is ~0.015 cts/s which converts to an unabsorbed flux of 9e-13 ergs cm^-2 s^-1 from 0.2-10keV.