NOTE: uvot_fluxes_wget.pl vrs. 2020-11-03a fem at 201222d02h48m54s767216usUT
NOTE: Source region spec. is: 171.05912 42.14319 4"
NOTE: Used archived XRT position of 171.05912  42.14319  4.00
NOTE: position reference is GCN_Circulars-29119

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

GRB 201221D: Swift/UVOT Upper Limits

A. A. Breeveld (UCL-MSSL) 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 201221D
92 s after the BAT trigger (Page et al., GCN Circ. 29112).
No optical afterglow consistent with the XRT position
(Evans et al. GCN Circ. 29119)
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            92          242          147         >20.0
u_FC               305          554          246         >19.9
white               92         4247          363         >20.8
v                  634         4657          216         >20.1
u                  305         5110          282         >19.9
w1                 684         5068          216         >19.5
m2                4663         4863          197         >19.7
w2                4253         4453          197         >20.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).