[vsnet-grb-info 3331] GRB 060526: ROTSE-III Observations of Optical Counterpart

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  5166
SUBJECT: GRB 060526: ROTSE-III Observations of Optical Counterpart 
DATE:    06/05/26 21:36:39 GMT
FROM:    Eli Rykoff at U of Michigan/ROTSE  <erykoff at umich.edu>

E.S. Rykoff (U Mich), S.A. Yost (U Mich), H. Swan (U Mich), W. 
Rujopakarn (U Mich), report on behalf of the ROTSE collaboration:

ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia, 
responded to GRB 060526 (Swift trigger 211957, GCN 5162). The first 
image was at 17:15:11.1 UT, 2801.1 s after the burst.  The unfiltered 
images are calibrated relative to USNO A2.0.  We detect a 17.5th 
magnitude, fading source with coordinates:

   15:31:18.3    +00:17:03.7 (J2000)

This is consistent with the Swift/UVOT position reported in GCN 5162.

The afterglow did not fade significantly between 2800s and ~6000s 
post-burst, when it was at ~ 17.5 mag.  At 6000s the lightcurve had a 
break, and started decaying as a smooth power-law with index ~-1.  At 
13000 s post-burst, the afterglow is at 18.4+/-0.05 mag.  Observations 
are continuing.

A jpeg image is available at 
http://www.rotse.net/images/gsb211957_3c091-100_key.jpg