GCN Circular 31801

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

The Swift/UVOT began settled observations of the field of GRB 220325A
114 s after the BAT trigger (Ferro et al., GCN Circ. 31787
Not found
 
 
).
No optical afterglow consistent with the XRT position
(Osborne et al. GCN Circ. 31790
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           114          264          147         >20.8
u_FC               326          576          246         >20.1
white              114         5035          488         >21.0
v                  657         1234           78         >18.7
b                  582         4893          255         >20.1
u                  326         4688          481         >20.3
w1                 707          726           19         >17.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.915 in the direction of the burst
(Schlegel et al. 1998).