GCN Circular 5601
M. Perri, M. Capalbi, M.L. Conciatore (ASDC), D.N. Burrows (PSU) and M. Stamatikos (NASA/ORAU) report on behalf of the Swift XRT team: We have analysed the first four orbits of Swift XRT data on the BAT GRB 060923C (Stamatikos, et al., GCN Circ. 5591). A 5.5 ks Photon Counting mode image provides a refined XRT position: RA(J2000) = 23h 04m 28.49s Dec(J2000) = +03d 55' 26.6" with an uncertainty of 5.9" (90% containment). This is 2.4' away from the center of the BAT refined position (Barthelmy et al., GCN Circ. 5600) and 6.9" away from the first XRT position quoted in GCN Circ. 5591 (Stamatikos, et al.). This position lies 2.8" from the object reported by Rau et al. (GCN Circ. 5598). The 0.3-10 keV X-ray light curve from T+212 s to T+13 ks can be fit by a broken power law model with temporal break at T+780s (+/-120s) and decay indices -3.4 (+/-0.2) and -0.6 (+/-0.2) before and after the break, respectively. The X-ray spectrum covering the time period from T+212s to T+275s is well fit by an absorbed power-law with a photon index of 1.85 (+/-0.13) and a column density consistent with the Galactic value in the direction of the burst (5.3e20 cm**-2). Assuming the X-ray emission continues to decline at the same rate, we predict a 0.3-10 keV XRT count rate of ~0.01 count/s at T+24hr, which corresponds to an observed 0.3-10 keV flux of ~5e-13 erg/cm**2/s. This circular is an official product of the Swift XRT Team.