GCN Circular 7354
A. Moretti (INAF-OAB), J. Mao (INAF-OAB), C. Guidorzi (Univ. Bicocca & INAF-OAB) report on behalf of the Swift-XRT team: We have analysed the Swift-XRT observation of GRB 080229B detected by SuperAgile (Evangelista et al. GCN Circ). The data consist of 13.4 ks in Photon Counting (PC) mode starting 27 hours after the SuperAGILE trigger and ending at 48 hours. We found a fading, uncatalogued X-ray source at the position: RA:199.25169 Dec:-64.86239 which is equivalent to: RA(J2000) = 13h 17m 00.40s Dec(J2000) = -64d 51' 44.6" with an uncertainty of 3.9 arcseconds (radius, 90% containment). This location is 73 arcseconds from the SuperAGILE position. The afterglow is decaying with a power-law slope of 0.9+/-0.5. The spectral parameters are poorly constrained due to the paucity of the statistics (~100 photons). The spectrum can be modelled with a power-law of photon index Gamma = 2.8 +/- 1.0, with an absorbing column of NH = (1.4 +/- 0.7)e22 cm^-2 (consistent with the Galactic value of 8.9e21 cm^-2). If the light-curve continues to decay with a slope of 0.9, the afterglow at 3 days (March 4th) will have an expected count rate of 0.0085 count s-1. This corresponds to an observed (unabsorbed) flux of 5.8E-13 (2.2e-12) ergs cm-2 s-1. This circular is an official product of the Swift-XRT team.