NOTE: uvot_fluxes_wget.pl vrs. 2018-01-16 fem at 180504d23h32m29s890699usUT
NOTE: Source region spec. is: 331.14421 -14.65833 4"
NOTE: Used archived XRT position of 331.14421 -14.65833  4.00
NOTE: position reference is GCN_Circulars-22683

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

GRB 180504A: Swift/UVOT Upper Limits

J. D. Gropp (PSU) and A. Y. Lien (GSFC/UMBC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180504A
118 s after the BAT trigger (Lien et al., GCN Circ. 22682).
No optical afterglow consistent with the XRT position
(Evans GCN Circ. 22683)
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           118          267          147         >20.1
u_FC               276          526          246         >19.6
white              118         1030          295         >20.4
u                  276          526          246         >19.6

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.04 in the direction of the burst
(Schlegel et al. 1998).