NOTE: uvot_fluxes_wget.pl vrs. 2020-11-03a fem at 210324d17h40m03s295432usUT
NOTE: Source region spec. is: 317.94721 25.36922 3"
NOTE: Used archived opt source position of 317.94721  25.36922  3.00
NOTE: position reference is GCN_Circulars-29703

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

GRB 210323A: Swift/UVOT Upper Limits

A. A. Breeveld (UCL-MSSL) and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210323A
88 s after the BAT trigger (Gropp et al., GCN Circ. 29699).
No optical afterglow consistent with the optical position
(Malesani et al. GCN Circ. 29703)
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            88          238          147         >20.1
u_FC               302          552          246         >20.1
white               88         4948          569         >20.8
v                  631         1423           97         >18.3
b                  557         1521           97         >19.8
u                  302         1497          324         >19.8
w1                 680         1472           97         >18.9
m2                 828          848           19         >18.6
w2                 607         5033          136         >20.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.131 in the direction of the burst
(Schlegel et al. 1998).