GCN Circular 3337
Subject
Swift UVOT refined analysis
Date
2005-05-02T22:32:34Z (19 years ago)
From
Patricia Schady at MSSL/Swift <ps@mssl.ucl.ac.uk>
P. Schady (MSSL), A. Falcone (PSU), S. Holland (GSFC/NRC), S. Koch (PSU), A.
Breeveld, K. Mason (MSSL), J. Nousek (PSU), N. Gehrels (GSFC) on behalf of the
UVOT Swift team
On further analysis of the Swift UVOT data, the afterglow candidate reported in
GCN 3330 (Falcone et al.) is not observed in the 1 x 1 binned first 100 sec
exposure taken in the V filter.
Starting with data taken ~192s after the BAT trigger (Falcone et al., GCN 3330)
we have co-added the early time data of GRB 050502b in each of the UVOT V, B
and U bands. The co-added images are made up of 9 x 10s exposures. No source is
detected at the position of the afterglow candidate reported in GCN 3330
(Falcone et al.) or within the XRT error circle (Pagani et al., GCN 3333) in
any of the bands. We estimate the five sigma magnitude upper limits from the
co-added images to be:
Filter Upper limit
V 18.5
B 19.4
U 19.2
The magnitudes are based on preliminary zero-points, measured in orbit,
and will require refinement with further calibration.