GCN Circular 23367

GRB 181022A: Swift/UVOT Upper Limits

S. J. LaPorte (PSU) and F. E. Marshall (NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181022A
78 s after the BAT trigger (Marshall et al., GCN Circ. 23364
Not found
 
 
).
No optical afterglow consistent with the XRT position
(Marshall et al. GCN Circ. 23364
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

u_FC                98          347          246         >20.5
v                   78         4922          288         >19.8
u                   98         5429          503         >20.4
w1                 661         5332          274         >20.1
m2                4927         5127          197         >20.2
w2                 356         4717          442         >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).