GCN Circular 23336

N. P. M. Kuin (UCL-MSSL) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181013A 106 s
after
the BAT trigger (D'Avanzo et al., GCN Circ. 23332
Not found
 
 
). No optical afterglow
consistent
with the XRT position (Osborne et al. GCN Circ. 23334
Not found
 
 
) 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           867         1017          147         >20.2
u_FC               266          516          246         >19.1
white              867         1017          147         >20.2
u                  266          516          246         >19.1
w1                 818         7875          471         >20.4
m2                6035         7669          393         >19.6
w2                5624         7260          393         >20.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.01 in the direction of the burst
(Schlegel et al. 1998).