GCN Circular 9899
Subject
GRB 090904A: Swift/UVOT Refined Analysis
Event
Date
2009-09-05T05:46:33Z (17 years ago)
From
Tyler Pritchard at PSU <tapritchard@astro.psu.edu>
T. A. Pritchard (PSU), C. A. Swenson (PSU) and M. Perri (ASDC) report on
behalf of the
Swift/UVOT team:
The Swift/UVOT began settled observations of GRB 090904A, 141 seconds
after the
BAT trigger (M. Perri et al., GCN Circ. 9879). We do not detect any
source at the
UVOT-enhanced XRT position (M.R. Goad, GCN Circ. 9885).
The 3-sigma upper limits for the exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag (3-sigma upper limit)
-------------------------------------------------------------
white 141 1189 341 > 21.57
v 629 1078 58 > 18.72
b 555 1177 58 > 19.59
u 299 1152 285 > 20.43
uvw1 679 1127 58 > 19.11
uvm2 827 847 19 > 17.61
uvw2 605 1054 58 > 19.17
-------------------------------------------------------------
The quoted upper limits have not been corrected for the expected
Galactic extinction corresponding to a reddeningalong the line of sight of
E_(B-V) = 0.1 mag (Schlegel et al., 1998, ApJS, 500, 525). All
photometry is on the
UVOT photometric system described in Poole et al. (2008, MNRAS, 383, 627).