GCN Circular 18075

N.P.M. Kuin(MSSL/UCL) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 150724B
88.6ks after the LAT trigger (Bissaldi et al., GCN Circ. 18065
Not found
 
 
),
which was also observed at high energy by Fermi-GBM (Veres et al.,
GCN Circ 18066) and Konus-Wind (Golenetskii et al. GCN Circ. 18074
Not found
 
 
).
Five UVOT exposures were obtained of which the first two show a
weak detection at the XRT position (Osborne et al., GCN Circ. 18069
Not found
 
 
).

Preliminary magnitudes and 3-sigma upper limits using the UVOT
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373)
are:

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

white            88619      88799          178        19.64+-0.12
white            88802      90608         1765        20.99+-0.14
white            90614      90748           60        >19.53
white            94379      94558          176        >20.82
white            94562      96236         1648        >22.01

The brightness is consistent with the RATIR observation at 147ks
in r and i (Butler et al, GCN 18072
Not found
 
 
).

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.06 in the direction of the burst
(Schlegel et al. 1998).