TITLE: GCN CIRCULAR NUMBER: 32609 SUBJECT: GRB 220930A: Swift/UVOT Upper Limits DATE: 22/09/30 20:39:10 GMT FROM: Alexander Belles at PSU/Swift aub1461@psu.edu
A. Belles (PSU) and S. B. Cenko (GSFC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 220930A 180 s after the BAT trigger (Cenko et al., GCN Circ. 32603). No optical afterglow consistent with the XRT position (Evans et al. GCN Circ. 32608) 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
wh_FC 180 330 147 >20.71 u_FC 338 588 245 >19.95 wh 618 1368 225 >20.93 v 669 1418 97 >18.73 b 594 1343 77 >19.59 u 744 1318 58 >18.99 w1 719 1467 77 >18.83 m2 693 1442 77 >18.59 w2 644 1393 97 >19.10
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.639 in the direction of the burst (Schlegel et al. 1998).