GCN Circular 9432
Subject
GRB 090529: Preliminary Swift/UVOT Upper Limit
Date
2009-05-29T17:12:13Z (15 years ago)
From
Stephen Holland at USRA/NASA/GSFC/SSC <sholland@milkyway.gsfc.nasa.gov>
S. T. Holland (CRESST/GSFC/USRA), F. E. Marshall (NASA/GSFC),
P. Schady (MSSL-UCL), and T. Sakamoto (NASA/UMBC) report on the behalf
of the Swift UVOT team:
The Swift/UVOT took a 150 s exposure of the field of GRB 090529
with its white filter starting 204 s after the BAT trigger (Sakamoto,
et al., 2009, GCN Circ. 9430). The preliminary 3-sigma upper limit at
the XRT position is white > 20.3. This upper limit has not been
corrected for the expected Galactic extinction along the line of sight
corresponding to a reddening of E_{B-V} = 0.02 mag (Schlegel, et al.,
1998, ApJS, 500, 525). The photometry is on the UVOT photometric
system described in Poole et al. (2008, MNRAS, 383, 627).
The non-detection in the white filter at 204 s, combined with the
observation at 28 minutes of R ~ 19.4 (Xin, et al., 2009, GCN Circ.
9431) implies either that this afterglow is unusually red, or that it
has brightened during the first half hour after the BAT trigger. Such
a long brightening would be highly unusual (Oates, et al., 2009,
MNRAS, 395, 450).