TITLE: GCN CIRCULAR NUMBER: 5695 SUBJECT: GRB 061004: Swift-XRT Team Refined Analysis DATE: 06/10/05 01:32:12 GMT FROM: Kim Page at U.of Leicester K.L. Page, A.P. Beardmore (U. Leicester) & H. Ziaeepour (UCL-MSSL) report on behalf of the Swift-XRT Team: We have analysed the first 2 orbits of Swift-XRT data obtained for GRB 061004 (GCN Circ. 5691; Ziaeepour et al.). Using 3.8 ks of Photon Counting mode data, we derive a refined position of: RA(J2000) = 06 31 10.48 Dec(J2000) = -45 54 24.6 with an estimated error radius of 5.5 arcsec (90% confidence, including boresight uncertainties). This lies 0.7 arcsec from the original XRT position given in GCN Circ. 5691 and 14.2 arcsec from the ground-calculated BAT position in GCN Circ. 5694 (Krimm et al). The X-ray light-curve shows an initial decay of alpha = 1.62 +/- 0.14, breaking around 375 seconds after the burst to a flatter decay slope of 0.61 +/- 0.10. The WT spectrum can be modelled using a power-law of Gamma = 1.53 +/- 0.48, absorbed by the Galactic column of 5.7e20 cm^-2. There is no evidence for any excess NH. The mean observed (unabsorbed) flux over 0.3-10 keV for this spectrum (spanning a time of 68-86 seconds after the trigger) is 2.83e-10 (3.07e-10) erg cm^-2 s^-1. If the decay continues with a slope of alpha ~ 0.61, the count rate at 24 hours after the burst is predicted to be 0.012 count s^-1. Using a conversion factor of 1 count s^-1 being approximately equivalent to 4.6e-11 erg cm^-2 s^-1 (observed flux), this corresponds to a flux of 2.8e-11 erg cm^-2 s^-1 (over 0.3-10 keV). The predicted unabsorbed flux at 24 hours is 3.2e-11 erg cm^-2 s^-1. This circular is an official product of the Swift-XRT team.