GCN Circular 37263

GRB 240824A: Swift/UVOT Upper Limits

N. P. M. Kuin (UCL-MSSL) and S. B. Cenko (GSFC)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 240824A
139 s after the BAT trigger (Cenko et al., GCN Circ. 37254
Not found
 
 
).
No optical afterglow consistent with the BAT position 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         >19.8
u_FC               297          547          246         >19.2
white              139         1717          411         >20.6
v                  628         1767          136         >18.7
b                  553         1866          136         >19.5
u                  297         1841          362         >19.5
w1                 677         1817          136         >19.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.014 in the direction of the burst
(Schlegel et al. 1998).