TITLE:   GCN CIRCULAR
NUMBER:  33289
SUBJECT: GRB 230205A: Swift/UVOT Upper Limits
DATE:    23/02/06 20:44:18 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>

M.H. Siegel (PSU) and E/ Ambrosi (INAF-IASFPA)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 230205A
100 s after the BAT trigger (Ambrosi et al., GCN Circ. 33271).
No optical afterglow consistent with the XRT position
(Goad et al. GCN Circ. 33275)
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         >21.3
u_FC               258          508          246         >20.3
white              100         5198          526         >21.5
v                  588         1581          117         >19.5
b                  514         1680          117         >20.1
u                  258         1481          343         >20.2
w1                 638          657           19         >19.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.036 in the direction of the burst
(Schlegel et al. 1998).