TITLE:   GCN CIRCULAR
NUMBER:  7690
SUBJECT: GRB 080506: Observations from NOT
DATE:    08/05/07 05:51:42 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte@iaa.es>

A. de Ugarte Postigo (ESO), C. C. Thoene,
J. P. U. Fynbo (DARK/NBI),  E. Leitet (Uppsala Univ.) and
L. M. Trinchant (Stockholm Univ.) report on behalf of a
larger collaboration:

We have observed the field of GRB 080506 (Baumgartner
et al., GCN 7685) using the 2.5m NOT telescope (+ALFOSC)
at Roque de Los Muchachos Observatory, in La Palma (Spain)
using U, B and R filters. A 300s R-band observation with
mid exposure time 7.1518 May 2008 UT (9.87hr after the burst)
reveals the object at a magnitude of 21.05 ± 0.11, using the
reference stars given in GCN 7686 for calibration. Combining
this datapoint with those of Kawabata et al. (GCN 7686),
Kann et al. (GCN 7688) and Kocka et al. (GCN 7689, where
it should say R= 20.2+/-0.4, private communication) we measure
a decay rate of  alpha = 0.64 ± 0.02 (f~t^-alpha), consistent with
the value reported by Kann et al. The object is clearly detected in
all filters, including the U-band frame, implying a redshift < 3.