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GCN Circular 32958

Subject
GRB 221120A: Swift/UVOT Upper Limits
Date
2022-11-21T04:53:00Z (a year ago)
From
Paul Kuin at MSSL <npkuin@gmail.com>
Paul Kuin (MSSL/UCL) and Rob Eyles-Ferris (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 221120A
208 s after the BAT trigger (Eyles-Ferris et al., GCN Circ. 32955).
An optical detection in r' has been reported by O'Connor et al.
(GCN Circ. 32957).
No optical afterglow consistent with the enhanced 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

u_FC               208          458          246         >19.9
white              761          911          295         >21.0
u                  208          458          246         >19.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.093 in the direction of the burst
(Schlegel et al. 1998).
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