GCN Circular 10326
R. Margutti (INAF-OAB), B. Sbarufatti (OAB), J. R. Cummings (NASA/GSFC/UMBC), M. De Pasquale (MSSL/UCL) report on behalf of the Swift-XRT team: Swift began observing the field of the Swift BAT Slew Survey (BATSS) GRB 100115A (Cummings et al. GCN Circ. 10325) 40ks after the trigger. Using 2.5 ks of XRT Photon Counting mode data we detect a single X-ray source source inside the BAT error circle at RA, DEC= 3.3664, -0.8263 which is equivalent to: RA (J2000): 00h 13m 27.93s Dec (J2000): -00d 49' 34.8" with an uncertainty of 6.8 arcsec (radius, 90% confidence). The source is detected at a level of 6.6x10^-3 count sec^-1. Given the current statistics it is not possible to determine whether this source is fading. A tentative spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.7 (+1.7, -0.8). The best-fitting absorption column is consistent with the Galactic value of 3.1 x 10^20 cm-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.9 x 10^-11 (3.6 x 10^-11) erg cm^-2 count^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020126. This circular is an official product of the Swift-XRT team.