GCN Circular 12631
C. A. Wolf (PSU), E. A. Hoversten (PSU), and T. Sakamoto (GSFC/UMBC) report on behalf of the Swift team: We have analyzed 2.85 ks of XRT data for the BAT ground-detected burst: GRB 111208A (Sakamoto et. al. GCN Circ. 12628), from 24.3 ks to 34.9 ks after the burst. The data are entirely in Photon Counting (PC) mode. An uncataloged X-ray source is detected within the BAT error circle and is potentially the afterglow of GRB 111208A. The refined XRT position is RA, Dec = 290.2251, +40.6766 which is equivalent to: RA (J2000); 19 20 54.0 Dec(J2000): +40 40 35.8 with an uncertainty of 4.1 arcsec (radius, 90% confidence). This position is 39.7 arcsec from the BAT position, within the BAT error circle. This position may be improved as more data are received. We cannot determine whether the source is fading at the present time. The Swift/UVOT began settled observations of the field of GRB 111208A 24.3 ks after the BAT trigger. No optical afterglow consistent with the XRT position is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the initial exposures are: Filter T_start(ks) T_stop(ks) Exp(s) Mag white 24.3 34.9 2100 >22.0 The magnitude in the table is not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.12 in the direction of the burst (Schlegel et al. 1998). We note that this is a crowded field and that there is a source a few arcseconds outside the XRT error circle. However, this source is clearly visible in archival optical imaging.