TITLE: GCN CIRCULAR NUMBER: 35458 SUBJECT: GRB 240101B: Swift/UVOT Upper Limits DATE: 24/01/02 12:11:38 GMT FROM: Paul Kuin at MSSL npkuin@gmail.com
N. P. M. Kuin (UCL-MSSL) and S. B. Cenko (GSFC) report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 240101B 110 s after the BAT trigger (Cenko et al., GCN Circ. 35449). 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 (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 134 284 147 >21.1 u_FC 294 543 246 >20.1 white 134 1718 411 >21.8 v 110 1595 130 >19.2 b 549 1693 117 >20.5 u 294 1669 343 >20.2 w1 675 1644 117 >19.3 m2 648 1619 97 >21.0 w2 599 1741 134 >19.3
The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.287 in the direction of the burst (Schlegel et al. 1998).
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