GCN Circular 26024

M. H. Siegel and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 191016A
45 ks after the BAT trigger (Gropp et al., GCN Circ. 26008
Not found
 
 
).  A 
source is detected consistent with the XRT position and the optical source reported
by Watson et al. (GCN Circ. 26010
Not found
 
 
, 26015
Not found
 
 
), Zheng and Filippenko (GCN Circ. 26011
Not found
 
 
),
Hu et al. (GCN Circ. 26017
Not found
 
 
), Kim et al. (GCN Circ. 26018
Not found
 
 
) and Toma et al.
(GCN Circ. 26019
Not found
 
 
).

The preliminary UVOT position is:
    RA  (J2000) =  02:01:04.68 =  30.26948 (deg.)
    Dec (J2000) = +24:30:35.7  =  24.50990 (deg.)
with an estimated uncertainty of 0.5 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limit using the UVOT photometric
system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures
are:

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

white            45023        46878         1822        21.09+/-0.17
white            50812        52638         1794        21.21+/-0.19
white            56420        56938          506        >21.23

The magnitudes in the table are not corrected for the Galactic extinction due
to the reddening of E(B-V) = 0.09 in the direction of the burst (Schlegel et al. 1998).