GCN Circular 23317

S.W.K. Emery (UCL-MSSL) and A. Melandri (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 181010A
96 s after the BAT trigger (Melandri et al., GCN Circ. 23309
Not found
 
 
).
A source consistent with the XRT position
(Evans et al. GCN Circ. 23313
Not found
 
 
)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  03:30:16.89 =  52.57038 (deg.)
    Dec (J2000) = -23:02:15.4  = -23.03761 (deg.)
with an estimated uncertainty of 0.49 arc sec. (radius, 90% confidence),

consistent with (MASTER-OAFA, Gorbovskoy et al., GCN Circ. 23310
Not found
 
 
;
LCO Cerro Tololo, Martone et al., GCN Circ. 23311
Not found
 
 
; RATIR, Troja et al., GCN Circ. 23312
Not found
 
 
;
VLT/X-shooter, Vielfaure et al., GCN Circ. 23315
Not found
 
 
)

Preliminary detections and 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            96          246          147        19.42 +/- 0.09
white              589         6359          247        >21.0
v                 3867         5503          393        >19.4
b                  564         6323          413        >20.9
u                  309         6117          639        >20.6
uvw1              4277         5912          393        >20.1
uvm2              4072         5707          393        >20.7
uvw2              5098         5298          197        >20.5

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.03 in the direction of the burst
(Schlegel et al. 1998).