GCN Circular 13001
Subject
GRB 111222A: Swift observation on 2012 February 06/07
Date
2012-03-02T18:08:01Z (12 years ago)
From
Dirk Grupe at PSU/Swift-XRT <dxg35@psu.edu>
D. Grupe and M. Siegel (PSU) report on behalf of the Swift team:
Swift re-observed the field of the IPN burst GRB 111222A (Hurley et
al., GCN circ. 12714) on 2012-02-06/07 for 5.1 ks. We do not
detect the X-ray source reported by Grupe (GCN circ. 12716) in a
2.5 ks observation 27 hours after the burst. The 3-sigma upper
limit at the position of the afterglow is 1.4e-3 counts/s in the
Swift XRT. This observation confirms our findings from a 5 ks Swift
observation obtained on 2011-12-31 (Grupe & Siegel, GCN circ.
12805) that the source has faded. We therefore conclude that the
X-ray source reported by Grupe (GCN circ. 12716) is the afterglow
of GRB 111222A.
UVOT observations show that the source reported in Grupe & Siegel
(GCN circ. 12805) has remained at constant white magnitude of
19.88 since fading by 0.48 magnitudes between the first and
second Swift/UVOT observations. Multi-color photometry confirms
that the source is very red (B-V=1.26), with only upper limits in
UV passbands). Its relation to the burst is still unknown.
The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020194.
This circular is an official product of the Swift team.