GCN Circular 8740
Subject
GRB 081226B: Swift XRT and UVOT upper limits
Event
Date
2008-12-27T10:02:56Z (17 years ago)
From
Phil Evans at U of Leicester <pae9@star.le.ac.uk>
P.A. Evans (U. Leicester) and E.A. Hoversten (PSU) report on behalf of
the Swift team:
Swift observed the field of GRB 081226B (Mereghetti et al. GCN Circ
8734) for 8 ks, beginning 9.6 ks after the INTEGRAL trigger. The XRT
data (all in Photon Counting mode) contain no source in the INTEGRAL
error circle. A 3-sigma upper limit is 0.001 counts/sec which is 5.6e-14
erg cm^-2 s^-1 for a typical GRB spectrum.
Given the absence of an XRT position, the UVOT images were compared to
archival images from the Digitized Sky Survey. No candidate afterglow
was found in the INTEGRAL error circle. UVOT magnitude 3-sigma upper
limits are reported in the following table:
Filter T_start T_stop Exp(s) Mag (3-sigma upper limit)
-------------------------------------------------------------
WHITE 9744 22737 1414 > 22.24
v 9621 27619 1940 > 20.48
b 9720 21824 1414 > 21.06
u 9694 16082 352 > 20.34
uvw1 10019 15877 313 > 20.20
uvm2 15472 28224 787 > 20.75
uvw2 10812 23271 932 > 21.27
The quoted upper limits have not been corrected for the expected
Galactic extinction along the line of sight of E_(B-V) = 0.01 mag.
All photometry is on the UVOT photometric system described in Poole et
al. (2008, MNRAS, 383, 627).
This circular is an official product of the Swift XRT and UVOT teams.