TITLE:   GCN CIRCULAR
NUMBER:  22758
SUBJECT: GRB 180602A: Swift/UVOT Upper Limits
DATE:    18/06/03 17:11:58 GMT
FROM:    Jeffrey Gropp at PSU  <jdg44@psu.edu>

J. Gropp (PSU) and S. B. Cenko (GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180602A
133 s after the BAT trigger (Cenko et al., GCN Circ. 22752).
No optical afterglow consistent with the enhanced XRT position
(Osborne et al. GCN Circ. 22753)
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           133          283          147         >19.9
u_FC               291          541          246         >19.8
white              133         1715          411         >20.8
v                  621         2283          194         >19.0
b                  547         2208          175         >20.0
u                  291         2183          401         >20.3
w1                 670         2159          175         >20.0
m2                 645          665           19         >18.7
w2                 597         2086          136         >20.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).