GCN Circular 35154

N.P.M. Kuin (MSSL/UCL) and S. L. Laha (GSFC/UMBC)
report on behalf of the Swift/UVOT team:

The initial Swift/UVOT observations of the field of GRB 231117A
(Laha et al., GCN Circ. 35071
Not found
 
 
) have been reported by Kuin and
Laha (GCN Circ. 35134
Not found
 
 
) based on the enhanced XRT position (Beardmore
et al. GCN Circ. 35074
Not found
 
 
). A refined position was published by
Yang et al. (GCN Circ. 35083
Not found
 
 
) which we use for the current
circular.

We report here exposures taken over the specified period and summed for
better S/N. We also report here in AB magnitudes (Breeveld et al. 2011,
AIP Conf. Proc. 1358, 373):

Filter         T_start(s)   T_stop(s)      Exp(s)           AB-Mag

white              106         1713          392         22.3 +/- 0.5
u                 5863       18,406          917         20.9 +/- 0.2
white           67,725       68,529          675         21.7 +/- 0.2
white          210,209      223,742         4848         22.4 +/- 0.4

Considering that these are AB magnitudes, we can compare the white and u
values to see a likely peak around the time of the u magnitude with a
subsequent decay.

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.071 in the direction of the burst
(Schlegel et al. 1998).