[vsnet-grb-info 11393] GRB 111222A: Second Swift observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  12805
SUBJECT: GRB 111222A: Second Swift observation 
DATE:    12/01/04 17:34:01 GMT
FROM:    Dirk Grupe at PSU/Swift-XRT  <dxg35 at 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.