NOTE: uvot_fluxes_wget.pl vrs. 2024-08-27 fem at 250917d18h03m14s790944usUT
NOTE: Source region spec. is: 291.378 +11.113 3"
NOTE: Used archived BAT position of 291.37800  11.11300
NOTE: position reference is GCN_Position_Notice

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

GRB 250917B: Swift/UVOT Upper Limits

***UBS*** (***INSTITUTION***) and Caputo (GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 250917B
139 s after the BAT trigger (Caputo et al., GCN Circ. 41848).
No optical afterglow consistent with the BAT position
*** POSITION REFERENCE is GCN_Position_Notice ***
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           139          289          147         >20.5
u_FC               351          601          246         >19.9
white              139         5391          492         >21.2
v                  681         1059           39         >18.1
b                  606         5225          236         >20.1
u                  351         5020          462         >20.1
w1                 730         4815          216         >18.9
m2                 705         1084           39         >18.8
w2                 831         1035           39         >19.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.983 in the direction of the burst
(Schlegel et al. 1998).