[vsnet-grb-info 2637] GRB 060110a: RAPTOR detection of early optical emission.

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4474
SUBJECT: GRB 060110a: RAPTOR detection of early optical emission.
DATE:    06/01/10 19:55:23 GMT
FROM:    Przemyslaw R. Wozniak at LANL  <wozniak at lanl.gov>

P.R. Wozniak, W.T. Vestrand, J. Wren, R. White, S. Evans
of Los Alamos National Laboratory report:

Our autonomous Raptor-S telescope responded to Swift trigger
176702 (Zane et al. GCN  4463) at 08:01:42.42 UT (6.8 seconds
after receiving the trigger).  We clearly detect a fading optical
source at the location of the IR counterpart identified by Bloom et al.
(GCN 4471).  The measurements show that the optical counterpart faded
from magnitude R=16.1+/-0.1 (5-second exposure) to about 17.5 over
the first ten minutes.  Our unfiltered magnitudes were calibrated
using R2 magnitudes of the field sources in USNO B1.0 catalog.