GCN Circular 9898
Subject
GRB 090904B: Swift/UVOT Refined Analysis
Event
Date
2009-09-05T05:45:47Z (17 years ago)
From
Tyler Pritchard at PSU <tapritchard@astro.psu.edu>
T. A. Pritchard (PSU) and D'Elia (ASDC) report on behalf of the
Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 090904B,
138 seconds
after the BAT trigger (D'Elia et al., GCN Circ. 9881). We do not detect
any source
at the UVOT-enhanced XRT position (J.P. Osbourne et al., GCN Circ.9887).
The 3-sigma upper limits for the exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag (3-sigma upper limit)
-------------------------------------------------------------
white 138 1357 369 > 22.17
v 625 1237 78 > 19.08
b 551 1335 78 > 20.08
u 295 545 246 > 20.41
-------------------------------------------------------------
The quoted upper limits have not been corrected for the highly uncertain
extinction
corresponding to a reddening along the line of sight of of E_(B-V) =
1.76 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).