NOTE: uvot_fluxes_wget.pl vrs. 2023-03-23 fem at 240419d02h03m46s421690usUT
NOTE: Source region spec. is: 239.37529 23.59583 4"
NOTE: Used archived XRT position of 239.37529  23.59583  4.00
NOTE: position reference is GCN_Circulars-36166
WARNING: Did not recognize UBS name.

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

GRB 240418A: Swift/UVOT Upper Limits

Shilling (***INSTITUTION***) and M. H. Siegel (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240418A
126 s after the BAT trigger (Siegel et al., GCN Circ. 36162).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-36166 ***
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           126          276          147         >20.6
u_FC               284          533          246         >19.6
white              126         5282          347         >20.9
v                 4072         4272          197         >19.9
b                  539         5093          216         >19.9
u                  284         4888          442         >20.1
w1                4482         4682          197         >19.9
m2                4276         4476          197         >20.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.057 in the direction of the burst
(Schlegel et al. 1998).