TITLE: GCN CIRCULAR NUMBER: 40619 SUBJECT: GRB 250603A: Swift/UVOT Upper Limits DATE: 25/06/03 13:14:52 GMT FROM: Samantha Oates at University of Birmingham samantha.oates@alumni.ucl.ac.uk
S. R. Oates (Lancaster U.) and T. M. Parsotan (GSFC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 250603A 105 s after the BAT trigger (Parsotan et al., GCN Circ. 40613). No optical afterglow consistent with the enhanced XRT position (Beardmore et al., GCN Circ. 40616) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure and subsequent exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white_FC 105 255 147 >20.4 u_FC 318 567 246 >19.7 white 105 1531 382 >21.0 v 647 5129 190 >19.0 b 573 1516 97 >19.6 u 318 1491 324 >19.8 w1 697 1467 78 >18.7 m2 672 1442 97 >18.5 w2 623 5029 294 >19.2
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 1.89 in the direction of the burst (Schlegel et al. 1998).
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