TITLE: GCN CIRCULAR NUMBER: 15592 SUBJECT: GRB 131209A: Swift XRT and UVOT observations DATE: 13/12/11 16:28:07 GMT FROM: Dirk Grupe at PSU/Swift-XRT Dirk Grupe (PSU) and Alice Breeveld (MSSL) report on behalf of the Swift team: We report on Swift observations of the field of the FERMI/LAT- discovered GRB 131209A (Vianello et al., GCN circ. 15587) starting 26.5 hours after the FERMI/LAT trigger. Swift performed three observations with and exposure tome of 3 ks each to cover most of the IPN error box reported by Hurley et al. (GCN circ. 15588). We found two X-ray sources with in the IPN error box, one of which coincides with a radio source, NVSS J090753-333724. The second source at the position RA-2000: 09 07 19.2 Dec-2000: -33 51 20.0 does not have an entry in the NED or Simbad. Its count rate in the XRT is at a level of (4.7+/-1.9)e-3 counts/s which is equivalent to a flux in the 0.3-10 keV band of (1.9+/-0.7)e-13 erg/s/cm2. Swift started observing the tile that covered this source 33 hours after the Fermi/LAT trigger (Vianello et al., GCN Circ. 15587). Only one of the XRT potential candidate sources (source 2) is in the field of view of the UVOT and there is no new source found at this position. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial summed exposures are: Filter T_start(hrs) T_stop(hrs) Exp(s) Mag white 33.16 33.37 754 >21.8 v 33.37 33.60 801 >20.1 u 32.94 34.78 1367 >21.1 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.36 in the direction of the burst (Schlegel et al. 1998).