GCN Circular 4669
A. D. Falcone (PSU), D. N. Burrows (PSU), D. C. Morris (PSU), N. Gehrels (GSFC) report on behalf of the Swift XRT team: We have analyzed the initial Swift XRT data from GRB 060204B (Falcone et al., GCN4655), with a total exposure of 178 s in Windowed Timing mode and 7790 s in Photon Counting mode. The refined XRT position is: RA(J2000) = 14 07 14.8 Dec(J2000) = +27 40 34 This position is 3" from the initial XRT on-board centroiding position reported in GCN 4655, and it is 2.8" from the optical detection reported by Guidorzi et. al (GCN 4661). We estimate an uncertainty of 4 arcseconds radius (90% containment). The early light curve is dominated by flaring with rates reaching approximately 200 c/s. Following the initial flaring, the light curve is clearly fading, but the rate is difficult to estimate due to the flaring and the limited data available at this time. A preliminary estimate of the power law decay index is approximately 0.6 +/- 0.4, immediately following the flaring activity. There is some indication that the lightcurve may become steeper beyond approximately 10 ks. Based on a preliminary spectral fit to the PC data in the time region between 200-5000 seconds, the spectrum can be described by an absorbed power law, with a power law photon index of 1.9 +/- 0.2 and N_H of 10e20 +/- 5e20 cm^-2. The 0.2-10 keV flux during this time frame is estimated to be approximately 4e-12 erg/cm^2/s. This Circular is an official product of the Swift XRT Team.