NOTE: uvot_fluxes_wget.pl vrs. 2023-03-23 fem at 240218d22h40m51s019091usUT
NOTE: Source region spec. is: 161.79683 1.27633 4"
NOTE: Used archived XRT position of 161.79683   1.27633  4.00
NOTE: position reference is GCN_Circulars-35748

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

GRB 240218A: Swift/UVOT Upper Limits

M. H. Siegel (PSU) 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 240218A
158 s after the BAT trigger (Page et al., GCN Circ. 35742).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-35748 ***
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           158          278          117         >20.5
white              158         2016          174         >20.7
v                 1703         1723           19         >17.9
b                 1802         1994           39         >19.4
w1                1577         1597           19         >18.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.045 in the direction of the burst
(Schlegel et al. 1998).