NOTE: uvot_fluxes_wget.pl vrs. 2020-11-03a fem at 210801d05h24m35s079862usUT
NOTE: Source region spec. is: 300.30358 -28.05950 4"
NOTE: Used archived XRT position of 300.30358 -28.05950  4.00
NOTE: position reference is GCN_Circulars-30568

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

GRB 210731A: Swift/UVOT Upper Limits

N. P. M. Kuin (UCL-MSSL) and E. Troja (NASA/GSFC/UMCP)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210731A
210 s after the BAT trigger (Troja et al., GCN Circ. 30568).
No optical afterglow consistent with the XRT position
(Troja et al. GCN Circ. 30568)
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 initial exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white              210          273           62         >20.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.092 in the direction of the burst
(Schlegel et al. 1998).