TITLE: GCN GRB OBSERVATION REPORT NUMBER: 4910 SUBJECT: GRB 060323: Swift XRT refined analysis DATE: 06/03/24 00:49:32 GMT FROM: Matteo Perri at ISAC/ASDC L. Vetere, M. Perri (ASDC), J.A. Kennea, D.N. Burrows (PSU) report on behalf of the Swift/XRT team: We have analysed the first five orbits of Swift XRT data on the BAT GRB 060323 (Vetere, et al., GCN 4904). The XRT began observing in Windowed Timing mode at 14:35:20 UT on 2006-03-23, 164 s after the BAT trigger. In the 0.3-10 keV energy band the afterglow shows a flat light curve from T+164s up to about T+800s, then it fades with a decay index of 1.2+/-0.1 up to T+20ks. The X-ray spectrum covering the time period from T+164s to T+614s is well fit by an absorbed power-law with a photon index of 1.9+/-0.3 and a column density consistent with the Galactic value in the direction of the source (1.54e20 cm**-2). The unabsorbed 0.3-10 keV flux for this spectrum is 7.5e-12 erg/cm**2/s. Assuming the X-ray emission continues to decline at the same rate, we predict a 0.3-10 keV XRT count rate of 0.002 count/s at T+24hr, which corresponds to an unabsorbed 0.3-10 keV flux of 1.1e-13 erg/cm**2/s. This circular is an official product of the Swift XRT Team.