GCN Circular 7754
Dirk Grupe reports on behalf of the Swift-XRT team: The XRT began observing the field of GRB 080520 (trigger=312047; Grupe et al., GCN Circ 7753) on 2008-May-20 at 22:22:04.3 UT, 99.5 seconds after the BAT trigger. The 0.3-10 keV X-ray light curve of the first two orbits displays a single decay with a slope alpha=1.04+/-0.07. The spectrum of the Photon Counting data of the first two orbits can be well fitted by an absorbed single powerlaw model with a photon index Gamma = 2.12 +/- 0.20 and a column density consistent with the Galactic value of 6.48e20 cm-2 If the underlying powerlaw decay continues as is, we predict an XRT count rate of 1e-3 counts/s at T+24 hours or 5e-14 ergs/s/cm2 and at T+48 hours 4e-4 counts/s or 2e-14 ergs/s/cm2. This circular is an official product of the Swift-XRT team.