TITLE:   GCN CIRCULAR
NUMBER:  10439
SUBJECT: GRB 100219A: GROND observations
DATE:    10/02/20 02:53:11 GMT
FROM:    Thomas Kruehler at MPE/MPI  <kruehler@mpe.mpg.de>

T. Kruehler (MPE), A. Nicuesa (Tautenburg Obs.), S. Klose (Tautenburg
Obs.), J. Greiner and P. Afonso (both MPE Garching) report on behalf of
the GROND team:

We observed the field of GRB 100219A (Swift trigger #412982; Rowlinson et
al., GCN #10430) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at LaSilla
Observatory (Chile).

Observations started on 20 February 2010 at 00:30 UT, 8.7 hours after the
GRB trigger.

Inside the XRT error circle (Evans et al., GCN #10437), we detect the
source mentioned in Jakobsson et al. GCN #10438, spatially separated by 3"
from the object mentioned in Holland et al. GCN#10432 and Bloom & Nugent
GCN #10433.

The object inside the XRT error circle is well detected in the r' band and
redder, but not in g'. Preliminary photometry yields an AB magnitude of
i'=21.5 calibrated against the GROND zeropoint at 9.0 hours after the
trigger. At the moment no statement about variability can be made.
However, if this is the afterglow of GRB 100219A, its colors indicate a
relatively high redshift event (z around 4.5).