TITLE:   GCN CIRCULAR
NUMBER:  37947
SUBJECT: GRB 241026A: Swift/UVOT Upper Limits
DATE:    24/10/29 21:43:50 GMT
FROM:    Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>

M. H. Siegel (PSU) and A. Melandri (INAF-OAR)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 241026A
118 s after the BAT trigger (Melandri et al., GCN Circ. 37896).
No optical afterglow consistent with the XRT position
(Osborne et al., GCN Circ. 37904) or the optical counterparts
(Moskvitin et al., GCN Circ. 37899; Watson, GCN. Circ. 37900; Shrestha
et al., GCN Circ. 37913) 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           118          268          147         >19.9
u_FC               331          581          246         >19.8
white              118         1708          411         >21.0
v                  662         1759          136         >19.8
b                  586         1849          128         >20.6
u                  331         1832          363         >20.2
w1                 712         1808          117         >20.7
m2                 686         1783          117         >20.7
w2                 636         1734          136         >20.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.073 in the direction of the burst
(Schlegel et al. 1998).