GCN Circular 3683
A. Moretti (INAF-OAB), S. Campana (INAF-OAB), P. Romano (INAF-OAB), L.A. Antonelli (INAF-OAR), M. Chester (PSU), P. Boyd (GSFC-UMBC) on behalf of the Swift-XRT Team report. We have analyzed the Swift XRT data from the first 3 orbit observation of GRB 050726 (Bathelmy et al., GCN 3682). As already reported an uncatalogued, fading X-ray source was detected by XRT at the following position: RA,Dec 13h 20m 12.30s -32d 03m 50.8s} (J2000) with an uncertainty of 6 arcsec (90% containment). The observations in Windowed Timing (WT) and Photon Counting (PC) mode start 132 and 334 seconds from the BAT trigger (T0) respectively. A preliminary spectral fit (simple absorbed power-law) to the WT data yields a photon index of 1.98-/+0.1 in the [0.5-10] keV band. The derived NH is (1.3)E21 cm^-2, which is higher than the Galactic value (0.4E+21 cm-2; Dickey & Lockman 1990). A preliminary spectral fitto the PC data yields values well consistent with the WT data. The light curve shows 2 highly significant flares in the first 200 seconds and then a monotonic fading which can be fitted with a power law of slope 1.06+-0.10 The unabsorbed 0.5-10.0 keV flux at 24 hours after the burst is then estimated to be 5E-13 ergs/s/cm2.