[vsnet-grb-info 6452] GRB 080804: Faulkes Telescope South observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8064
SUBJECT: GRB 080804: Faulkes Telescope South observations
DATE:    08/08/05 15:05:59 GMT
FROM:    Cristiano Guidorzi at INAF-OAB  <cristiano.guidorzi at brera.inaf.it>

C. Guidorzi (INAF-OAB) and I. Steele (LJMU) on behalf of a
larger collaboration report:

On 2008 August 05 (12:44:12 UT) we began observing the field of GRB 080804
(Racusin et al. GCN Circ. 8057) with the Faulkes Telescope South using
the R filter.

In our coadded frame we detect the optical afterglow at the position
fully consistent with that reported by Swift-UVOT (Racusin et al. GCN
Circ. 8057) and slighly outside the error circle given by ROTSE-III
(Rujopakarn et al. GCN Circ. 8056) which is 1.5 arcsec away.

Telescope   Filter  T_mid[hr]   Exposure[s]      Mag
-----------------------------------------------------------
FTS         R        14.235       1200         21.6 +/- 0.1
-----------------------------------------------------------

The calibration was performed using the R2 magnitudes of several
USNOB-1 catalogue field objects. The uncertainty reported above does
not include the additional ~0.3 mag of the USNOB-1 catalogue.
>From the comparison with the value reported by UVOT we infer an
average power-law decay index of ~0.7.