[vsnet-grb-info 17130] GRB 151023A: Swift/UVOT Upper Limits

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18462
SUBJECT: GRB 151023A: Swift/UVOT Upper Limits
DATE:    15/10/24 02:15:35 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel at swift.psu.edu>

M. H. Siegel (PSU), B. G. Balzer (PSU) 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 151023A
796 s after the BAT trigger (D'Avanzo et al., GCN Circ. 18450).
No optical afterglow consistent with the XRT position
(D'Avanzo et al. GCN Circ. 18450) 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           796          946          147         >19.6
white              796         2140          411         >20.0
v                 1130         2191          136         >18.5
b                 1229         2116          117         >19.3
w1                1354         1374           19         >18.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.42 in the direction of the burst
(Schlegel et al. 1998).