NOTE: uvot_fluxes_wget.pl vrs. 2023-03-23 fem at 230728d21h34m25s559687usUT
NOTE: Source region spec. is: 343.51571 28.17433 4"
NOTE: Used archived XRT position of 343.51571  28.17433  4.00
NOTE: position reference is GCN_Circulars-34286

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

GRB 230728A: Swift/UVOT Upper Limits

***UBS*** (***INSTITUTION***) and C. Salvaggio (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 230728A
100 s after the BAT trigger (Salvaggio et al., GCN Circ. 34282).
No optical afterglow consistent with the XRT position
*** POSITION REFERENCE is GCN_Circulars-34286 ***
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           100          250          147         >21.0
u_FC               312          562          246         >19.9
white              100         1362          373         >20.9
v                  641         5845          274         >19.6
b                  567         1337           78         >19.5
u                  312         1313          304         >20.3
w1                 691         1289           58         >19.5
m2                 665         6049          214         >19.8
w2                1023         1380           32         >18.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.080 in the direction of the burst
(Schlegel et al. 1998).