NOTE: uvot_fluxes_wget.pl vrs. 2020-11-03a fem at 210725d18h04m09s270091usUT
NOTE: Source region spec. is: 192.92217 17.10808 4"
NOTE: Used archived XRT position of 192.92217  17.10808  4.00
NOTE: position reference is GCN_Circulars-30510

=========== Draft Upper Limit Circular ========

GRB 210725B: Swift/UVOT Upper Limits

M. H. Siegel (PSU) and M. G. Bernardini (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210725B
92 s after the BAT trigger (Bernardini et al., GCN Circ. 30508).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 30510)
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                92          341          246         >20.5
b                  347          439           91         >20.0
u                   92          341          246         >20.5
w2                3722         3905          180         >19.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.023 in the direction of the burst
(Schlegel et al. 1998).