TITLE: GCN CIRCULAR NUMBER: 14859 SUBJECT: GRB 130610A: Swift/UVOT Observations DATE: 13/06/10 18:12:42 GMT FROM: Mike Siegel at PSU/Swift MOC M. H. Siegel (PSU) 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 130610A 140 s after the BAT trigger (Cummings et al., GCN Circ. 14842). A fading source consistent with the XRT position (Cummings et al. GCN Circ. 14842) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 14:57:40.88 = 224.42034 (deg.) Dec (J2000) = +28:12:25.8 = 28.20717 (deg.) with an estimated uncertainty of 0.51 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are listed below. The lack of detection in the NUV filters would be consistent with the z=2.1 redshift reported by Smette et al. (GCN Circ. 14848). Filter T_start(s) T_stop(s) Exp(s) Mag white (fc) 140 290 147 17.85+-0.04 white 1491 1857 58 19.56+-0.19 white 5267 6902 393 20.47+-0.15 v 1540 7312 451 >20.07 b 1467 2005 77 19.12+-0.20 b 6498 19320 1754 21.72+-0.38 u 298 441 140 17.67+-0.09 u 1614 1980 58 19.00+-0.30 uvw1 1589 1956 58 >19.05 uvm2 1911 23463 1298 >21.09 uvw2 1863 7108 412 >20.63 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel et al. 1998).