NOTE: uvot_fluxes_wget.pl vrs. 2020-11-03a fem at 220907d17h55m25s807797usUT
NOTE: Source region spec. is: 268.87142 -20.28794 4"
NOTE: Used archived XRT position of 268.87142 -20.28794  4.00
NOTE: position reference is GCN_Circulars-32527

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

GRB 220907A: Swift/UVOT Upper Limits

S. R. Oates (U.Birmingham) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 220907A
95 s after the BAT trigger (Page et al., GCN Circ. 32526).
No optical afterglow consistent with the XRT position
(Page and Evans GCN Circ. 32527)
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            95          245          147         >20.7
white               95         5001          298         >20.8
v                 3823         4023          197         >19.0
b                 4644         4844          197         >20.1
u                 4438         4638          197         >19.4
w1                4234         4433          197         >19.6
m2                4028         4228          197         >19.2
w2                3618         3818          197         >20.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.637 in the direction of the burst
(Schlegel et al. 1998).