GCN Circular 34240

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 230723B
3298 s after the BAT trigger (Page et al., GCN Circ. 34234
Not found
 
 
).
No optical afterglow consistent with the XRT position (Page and Evans, 
GCN Circ. 34238
Not found
 
 
)  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          3298         3448          147         >20.6
white             3298         4680          344         >20.9
v                 3456         3655          197         >19.1
b                 4276         4475          197         >20.1
u                 4070         4270          197         >20.0
w1                3866         4065          197         >19.3

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.411 in the direction of the burst
(Schlegel et al. 1998).