TITLE:   GCN CIRCULAR
NUMBER:  7902
SUBJECT: GRB 080623: GROND upper limits
DATE:    08/06/25 02:42:32 GMT
FROM:    Adria C. Updike at Clemson U  <aupdike@clemson.edu>

A. Updike (Clemson Univ.), S. Loew, J. Greiner, T. Kruehler,
A. Kuepcue Yoldas, A. Yoldas,  (all MPE Garching),
G. Szokoly (Eoetvoes Univ., Budapest and MPE Garching),
report for the GROND team:

We observed the field of GRB 080623 detected by Swift/BAT (Ukwatta et al.
2008, GCN 7894) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.
2008, PASP 120, 405), mounted at the 2.2m MPI/ESO telescope at La Silla
(Chile). A first epoch started on Jun. 23 at 22:50 UT (12.3 hrs after the
GRB) and continued for 2.5 hours; the second epoch was obtained on Jun. 24
at 23:50 UT (mid-time).

We do not detect any new source within the astrometrically corrected XRT
position (Beardmore et al. 2008, GCN 7898).

We note that there is a bright star at the border of the XRT error circle
and a fainter one just outside the XRT error circle.  A finding chart can
be found at http://www.mpe.mpg.de/~jcg/grb080623.html .  Both objects are
visible in DSS2-R and are constant between our two epochs.  Image
subtraction revealed no hidden sources.

Limiting magnitudes inside the XRT error circle are g'>24.3, r'>23.5,
i'>21.8, z'>21.7, J>20.2, H>19.4, K>17.5, calibrated against USNO-B1 and
2MASS stars.