GCN Circular 8252
Subject
GRB 080916B: Swift UVOT Refined Analysis
Event
Date
2008-09-17T00:42:53Z (18 years ago)
From
Erik Hoversten at Swift/Penn State <hoversten@astro.psu.edu>
E. A. Hoversten (PSU) and G. Stratta (ASDC) report on behalf of the
Swift UVOT team:
The Swift/UVOT began settled observations of the field of
GRB 080916B, 1359s after the BAT trigger (Stratta et al., GCN 8240).
There is a possible detection of an afterglow in the UVOT white filter
at:
RA (J2000) 10:54:39.78
Dec (J2000) 69: 3:57.9
with an estimated uncertainty of 0.8 arcsec (radius, 90% confidence).
This position is consistent with the UVOT enhanced XRT position (Evans
et al., GCN 8247). The afterglow candidate does not appear in the DSS
images, and photometry from the second orbit of Swift observations
suggests that it has faded.
UVOT magnitudes and 3-sigma upper limits are reported in the following
table:
Filter T_start T_stop Exp(s) Mag (3-sigma upper limit)
-----------------------------------------------------
white 1359.0 1458.8 98.2 20.50 +/- 0.21
white 7826.0 8025.7 196.6 > 21.27
v 1340.9 2920.7 342.1 > 19.62
b 1516.3 2676.5 155.6 > 20.32
u 1491.6 2651.7 155.6 > 19.91
uvw1 1467.3 2627.3 155.5 > 19.91
uvm2 1604.9 3076.8 285.0 > 20.06
uvw2 1556.0 2716.0 155.5 > 19.91
The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight of E_{B-V} = 0.02 mag.
All photometry is on the UVOT flight system described in Poole et al.
(2008, MNRAS, 383, 627).