NOTE: uvot_fluxes_wget.pl vrs. 2020-11-03a fem at 210618d06h34m54s070827usUT
NOTE: Source region spec. is: 235.820 +46.043 3"
NOTE: Used archived BAT position of 235.82000  46.04300
NOTE: position reference is GCN_Position_Notice

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

GRB 210618A: Swift/UVOT Upper Limits

N. P. M. Kuin (UCL-MSSL) and M. G. Bernardini (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 210618A
3728 s after the BAT trigger (Bernardini et al., GCN Circ. 30250).
No optical afterglow consistent with the BAT position
*** POSITION REFERENCE is GCN_Position_Notice ***
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          3728         3878          147         >20.4
white             3728         4496          344         >21.1
v                 4707         4843          133         >19.2
b                 4092         4291          197         >20.5
u                 3886         4086          197         >20.0
w2                4502         4702          197         >20.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.015 in the direction of the burst
(Schlegel et al. 1998).