GCN Circular 12805
Subject
GRB 111222A: Second Swift observation
Event
Date
2012-01-04T17:34:01Z (14 years ago)
From
Dirk Grupe at PSU/Swift-XRT <dxg35@psu.edu>
D. Grupe (PSU) 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 2011-12-31 for 5 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 anymore. The 3-sigma upper
limit at the position of the afterglow is 2.2e-3 counts/s in the
Swift XRT. We conclude that the X-ray source has faded and is the
afterglow of GRB 111222A.
Swift/UVOT observed the burst for 4.9 ks, with all data taken
in the white filter. We confirm the previously reported optical
source noted in Siegel and Grupe (GCN Circ. 12717) that was also
present in the DSS images. We find that the source has faded
significantly since the initial observation from a white magnitude
of 19.34+-0.03 to 19.89+-0.03. This implies that the previous
observation recorded light from both the host galaxy and the
optical afterglow of the burst. Further observations of the
host galaxy are strongly encouraged.
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.