TITLE: GCN CIRCULAR NUMBER: 7966 SUBJECT: GRB 080710: Swift-XRT refined analysis DATE: 08/07/10 22:14:47 GMT FROM: Boris Sbarufatti at INAF-IASF-Pa B. Sbarufatti, V. Mangano (INAF/IASF Pa) report on behalf of the Swift XRT team Swift XRT began observations of GRB 080710 (Sbarufatti et al., GCN Circ. 7957) at 08:02 UT, 49 minutes after the trigger. The refined position for the afterglow, obtained using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue (see Evans et al., GCN Circ. 7964) is RA, Dec = 8.27364, 19.50158 which is equivalent to: RA (J2000): 00 33 5.67 Dec (J2000): +19 30 05.7 with an uncertainty of 1.4 arcsec (radius, 90% confidence). The XRT observations consist of 7.9 ks in Photon Counting mode. The light-curve can be fitted by a simple power-law model with slope (1.0 +/- 0.1), with superposed flaring activity. The average spectrum can be modeled by a power-law with photon index 2.09 +/-0.1 and an intrinsic absorbing column of (1.6 +/-0.7) E21 cm^-2 at z=0.845 (Perley et al., GCN Circ. 7962) in excess with respect to the Galactic value (4.1E+20 cm^-2, Kalberla et al. 2005). The observed (unabsorbed) flux in the 0.3-10 keV band is 5.35 (5.84)E-12 ergs cm^-2 s^-1. The count rate to flux conversion factor is 4.1E-11. The predicted flux for tomorrow, 07:13 UT (24 h after the trigger) is 6.9E-13 ergs cm^-2 s^-1. This circular is an official product of the Swift XRT team.