[vsnet-grb-info 21268] GRB 181022A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23367
SUBJECT: GRB 181022A: Swift/UVOT Upper Limits
DATE:    18/10/23 03:30:07 GMT
FROM:    Sam LaPorte at PSU  <sjl5346 at psu.edu>

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).
No optical afterglow consistent with the XRT position
(Marshall et al. GCN Circ. 23364)
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).