TITLE: GCN CIRCULAR NUMBER: 7045 SUBJECT: GRB 071104: Swift-XRT Team Refined Analysis DATE: 07/11/05 08:15:55 GMT FROM: Kim Page at U.of Leicester K.L. Page (U Leicester) reports on behalf of the Swift-XRT Team: Seven orbits (15.6 ks) of Swift-XRT data have now been obtained and analysed for the SuperAGILE burst GRB 071104 (Donnarumma et al., GCN Circ 7042), all in Photon Counting mode. The XRT position was given in GCN Circ. 7043 and has not been further improved. Although the X-ray light-curve can, to first order, be fitted by a single power-law, there is an indication that the decay has broken (around 43 ks after the trigger) from an initial slope of alpha ~ 0.6 to a steeper value of ~2.9, although this decay slope is not well-constrained because of the limited data after the break time (a 90% range of alpha = 0.5 - 5.3 is estimated). A spectrum formed from all the data (20.5 - 50.9 ks after the trigger) can be modelled with a power-law of Gamma = 1.9 +/- 0.3 absorbed by the Galactic column density of 2.69e21 cm^-2. (The 90% upper limit on this absorption is 4.9e21 cm^-2.) Over this period, the 0.3-10 keV observed flux is 1.1e-12 erg cm^-2 s^-1, with the unabsorbed value being 1.5e-12 erg cm^-2 s^-1. Using the range of possible decay slopes, the count-rate is expected to be between 0.018 and 7e-4 count s^-1 at 24 hours, corresponding to an observed flux range of between 1.0e-12 and 4.0e-14 erg cm^-2 s^-1 over 0.3-10 keV (1.4e-12 - 5.4e-14 erg cm^-2 s^-1 unabsorbed). This circular is an official product of the Swift-XRT team.