TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  1193
SUBJECT: Fading of the optical source associated of XRF 011211
DATE:    01/12/12 12:48:54 GMT
FROM:    Josh Bloom at CIT  <jsb@astro.caltech.edu>

Fading of the optical source associated of XRF 011211

J. S. Bloom and Edo Berger report on behalf of the larger
Caltech-NRAO-CARA GRB Collaboration:

"Following the report of a new bright source (Grav et al. GCN #1191) in
the field of XRF 011211 (Gandolfi et al. GCN #1188, GCN #1189; Santos-Lleo
et al. GCN #1192) we began observing the source position with the Palomar
200" + JCAM dual-band optical imager on 12 Dec 01, 10:48 UT in very poor
observing conditions. In Sloan-r', the source is clearly fainter than the
three objects to the northwest (the source plus the three objects appear
to be of comparable brightness on the Grav et al. finding chart).  This
confirms the transient nature of the source discovered by Grav et al. and
helps solidify its association with XRF 011211.

The source was also detected the Sloan g' filter, suggesting an origin
z <~ 4.3.

A finding chart with a single g' and r' integration (110s and 100s
exposure) may be found at:

http://www.astro.caltech.edu/~jsb/xrf011211.gif

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