NOTE: uvot_fluxes_wget.pl vrs. 2023-03-23 fem at 230618d13h31m23s139848usUT
NOTE: Source region spec. is: 196.60525 3.30253 4"
NOTE: Used archived XRT position of 196.60525   3.30253  4.00
NOTE: position reference is GRB_Auto_Processing

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

GRB 230618A: Swift/UVOT Upper Limits

***UBS*** (***INSTITUTION***) 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 230618A
137 s after the BAT trigger (Page et al., GCN Circ. 33989).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GRB_Auto_Processing ***
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           137          287          147         >20.5
u_FC               296          546          246         >19.9
white              137         1539          392         >20.8
v                  626         1589          117         >19.1
b                  552         1515           97         >20.4
u                  296         1317          285         >20.0
w1                 675         5178          161         >19.3
m2                4909         5108          197         >19.5

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.025 in the direction of the burst
(Schlegel et al. 1998).