[vsnet-grb-info 15691] GRB 141028A: Swift/UVOT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16979
SUBJECT: GRB 141028A: Swift/UVOT Detection
DATE:    14/10/29 03:58:53 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel at swift.psu.edu>

M. H. Siegel (PSU) and C. Pagani (UL)  report on behalf of the
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 141028A
31037 s after the LAT trigger (Bissaldi et al., GCN Circ. 16969).
We detect an optical afterglow consistent with the afterglow reported by
MASTER (Gorbovsky et a., GCN, Circ 16972), GROND (Graham et al., GCN Circ.
16977) and the XRT (Kennea, et al., GCN Circ 16978).

The preliminary UVOT position is:
   RA  (J2000) =  21:30:24.54 = 322.60226 (deg.)
   Dec (J2000) = -00:13:52.4  =  -0.23122 (deg.)
with an estimated uncertainty of 0.4 arc sec. (radius, 90% confidence). This is
consistent with the GROND and MASTER positions.

Preliminary detection using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposure is:

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

u                31037        37759          233         19.14+-0.19

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.05 in the direction of the burst
(Schlegel et al. 1998).