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GCN Circular 37057

Subject
GRB 240805B: Swift/UVOT Upper Limits
Date
2024-08-06T01:35:51Z (a month ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
Via
Web form
M. H. Siegel (PSU) and M. Williams (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 240805B
88 s after the BAT trigger (Williams et al., GCN Circ. 37043).
No optical afterglow consistent with the XRT position
(Goad et al., GCN Circ. 37053) 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            88          238          147         >20.9
u_FC               301          551          246         >19.9
white               88         1719          411         >21.6
v                  630         1768          136         >19.4
b                  556         1694          117         >19.7
u                  301         1669          343         >20.2
w1                 679         1818          136         >19.6
m2                1256         1620           39         >19.2
w2                 606         1744          136         >20.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.087 in the direction of the burst
(Schlegel et al. 1998).
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