TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5106 SUBJECT: GRB060510A: XRT refined analysis DATE: 06/05/10 18:20:08 GMT FROM: Maria Laura Conciatore at ASDC M.L. Conciatore, M. Capalbi, M. Perri, L. Vetere (ASDC), H. A. Krimm (GSFC/USRA)D. Burrows (PSU) report on behalf of the Swift/XRT team: We have analysed the first orbit of XRT data from GRB 060510A. A 1.8ks Photon Counting (PC) mode image provides a refined XRT position: RA(J2000) = 06 23 28.0 Dec(J2000)= -01 09 44.2 with an uncertainty of 3.5 arcsec (90% containment). This position is 1.3 arcsec away from the ground-calculated XRT position quoted in Krimm et al. (GCN 5095), 15.2 arcseconds from the BAT position (GCN 5095) and it is consistent with the UVOT position given in GCN 5095. A power-law fit of the PC spectrum with a column density fixed to the Galactic one (4.1 e21 cm^-2) gives a photon index of 2.1+/-0.5. The 0.2-10.0 keV observed flux is 2.0E-10 erg cm^-2 s^-1, which corresponds to an unabsorbed flux of 3.2E-10 erg cm^-2 s^-1. The light curve shows a fast initial decay, followed by a flattening phase. At about 1.2 ks from the trigger, it starts to decay again. Further osbervations are ongoing. This circular is an official product of the Swift XRT Team.