TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5087 SUBJECT: GRB 060507: Swift XRT Team Refined Analysis DATE: 06/05/07 17:10:01 GMT FROM: Loredana Vetere at ASDC L. Vetere, M.L. Conciatore, M. Capalbi, M. Perri (ASDC), D.N. Burrows (PSU) and L. M. Barbier (NASA/GSFC) report on behalf of the Swift/XRT team: We have analysed the first 5 orbits of XRT data from GRB 060507 (Barbier et al., GCN 5084). A 11ks photon counting mode image provides a refined XRT position: RA(J2000) = 05 59 51.7 Dec(J2000) = +75 14 56.6 with an uncertainty of 4 arcsec (90% containment). This is 1 arcsec away from the initial XRT position quoted in GCN 5085 (Vetere et al.). The X-ray light curve decays with a single powerlaw, fitting the last 4 orbits we find a decay index of -1.0 +/- 0.1. A power-law fit to the X-ray spectrum from T+2.8ks to T+28.3ks gives a photon index of 2.1+/-0.1 and a column density of (1.7+/-0.4)e21 cm^-2. We note that the galactic hydrogen column density in the direction of the burst is 8.8e20cm^-2. The 0.2-10.0 keV observed flux is 2.2e-12 ergs cm^-2 s^-1, which corresponds to an unabsorbed flux of 3.4e-12 ergs cm^-2 s^-1. If the burst continues decaying at the current rate we estimate an XRT count rate of 0.009 counts/s at T + 24hr, which corresponds to an observed 0.2-10.keV flux of 6.8e-13 ergs cm^-2 s^-1. This circular is an official product of the Swift XRT Team.