TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4471
SUBJECT: GRB 060110: IR Candidate Afterglow
DATE:    06/01/10 12:29:54 GMT
FROM:    Josh Bloom at UC Berkeley  <jbloom@astron.berkeley.edu>

J. S. Bloom (UC Berkeley) reports:

"We have conducted further analysis on the source noted in GCNs  
4465/4467 and suggest that, while the source is formally outside of  
the 90% containment BAT error circle (e.g. Torii GCN 4468), there is  
evidence this is the (bright) afterglow of GRB 060110 (Zane al. GCN  
4463). This follows from a few lines of evidence:

   [1] evidence for fading. We created two mosaic epochs (1: 08:06:52  
-- 08:11:32; 2: 08:12:46 -- 08:30:36) and found that the average  
brightness decreased by ~0.12 mag in JHKs. We believe that this  
fading is significant but photometry is complicated by large  
background gradients owing to the proximity to the Moon.
   [2] no bright minor planets are nearby this position (see GCN 4467).
   [3] no evidence for apparent motion between the epochs (~<1"/hr)  
and point-like PSF.
     All the other minor planets in the field have significant  
motions, particularly in RA (>10"/hr)

Our current astrometric solution gives a position of the afterglow  
(in both epochs) to be:
    04:50:57.85 +28:25:55.7
(J2000; 200 mas uncertainty). This is close to the position noted by  
Torii (GCN 4468) and lends credence to their tentative R-band  
detection. Photometry in the second epoch yields magnitudes J =  
15.23, H = 14.25, Ks = 13.57 (absolute zp uncertainty of ~0.04 mag)."

Follow on observations are urged.