[AAVSO-HEN] GRB 080218B: GROND upper limits

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  7319
SUBJECT: GRB 080218B: GROND upper limits
DATE:    08/02/19 04:15:59 GMT
FROM:    Jochen Greiner at MPI  <jcg at mpe.mpg.de>

A. Rossi (Tautenburg Obs.), J. Greiner, A. K"upc"u Yoldas, and A. Yoldas
(MPE Garching) report for the GROND team:

We observed the field of GRB 080218B, Swift trigger 303631 (Schady et al. 2008,
GCN Circ. 7314) simultaneously in grizJHK with GROND (Greiner et al. 2008,
astro-ph/0801.4801) mounted at the 2.2m MPI/ESO telescope at La Silla (Chile).
Observations started at 00:37, 379 min after the GRB. At this time, the GRB 
location was becoming visible at 20 degrees above horizon.

Through thin cirrus, we do not detect any source inside the XRT error.
We estimate the following limits: g'>24.2, r'>24.2, i'>23.7, z'>23.4,
J>21.6, H>20.6, K>19.5, calibrated against USNO-B and 2MASS stars.
These values are not corrected for the substantial foreground extinction.