NOTE: uvot_fluxes_wget.pl vrs. 2018-01-16 fem at 180425d13h18m03s220683usUT
NOTE: Source region spec. is: 64.45158 -32.95217 4"
NOTE: Used archived XRT position of  64.45158 -32.95217  4.00
NOTE: position reference is GCN_Circulars-22673

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

GRB 180425A: Swift/UVOT Upper Limits

S.W.K. Emery (UCL-MSSL) and F. E. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180425A
89 s after the BAT trigger (Marshall et al., GCN Circ. 22672).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 22673)
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            89          238          147         >20.3
u_FC               302          552          246         >20.7
white               89         1201          353         >20.9
v                  631         1251           78         >18.9
b                  558         1177           58         >19.8
u                  302         1152          285         >20.8
w1                 680         1300           78         >19.8
m2                 828         1275           58         >19.7
w2                 607         1227           58         >19.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).