[vsnet-grb-info 3791] GRB 060926: Swift-UVOT Detections

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5625
SUBJECT: GRB 060926: Swift-UVOT Detections
DATE:    06/09/27 02:20:21 GMT
FROM:    Pete Roming at PSU  <roming at astro.psu.edu>

P. Roming (PSU) and S. T. Holland (GSFC/USRA) report on behalf of the Swift-UVOT
team:

The Swift UVOT began observing GRB 060926, 57 seconds after the BAT trigger (GCN
5612). We detect a source at the 4.8- and 4.3-sigma levels in the V- and UVW1-
(251 nm) filters, respectively. The magnitude of the source is 19.0+/-0.2
(V-filter) and 18.8+/-0.2 (UVW1-filter) as determined by the Swift analysis
tool, uvotsource.

No optical afterglow is detected at the 3-sigma level in individual or coadded
exposures in the UVOT UVW2-, UVM2-, U-, or B-filters. The 3-sigma limiting
magnitudes for the coadded images of the UVOT filters are listed below:

Filter		T_range(s)	Exp(s)		Upper Limit (3-sigma)
UVW2		551-6405	432		20.1
UVM2		463-10840	1366		20.4
U		511-12283	968		20.8
B		535-6199	422		20.6

where T_range is the start and end times of the coadded exposures. No correction
has been made for Galactic reddening along the line of sight (E(B-V) = 0.16).

No images were taken in the White-filter by the UVOT since bright stars were in
the field-of-view.