GCN Circular 17201
F. E. Marshall (NASA/GSFC) and J. R. Cummings (NASA/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 141220A 597 s after the BAT trigger (Cummings et al., GCN Circ. 17196). There were also other exposures when the spacecraft attitude was not stable. A source consistent with the optical position Gorosabel et al. (GCN Circ. 17197) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 13:00:15.76 = 195.06565 (deg.) Dec (J2000) = +32:08:47.0 = 32.14639 (deg.) with an estimated uncertainty of 0.45 arc sec. (radius, 90% confidence). Preliminary detections using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 597 617 19 17.30 � 0.07 v 647 839 39 17.65 � 0.16 b 573 593 20 17.58 � 0.13 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.01 in the direction of the burst (Schlegel et al. 1998).