[AAVSO-HEN] GRB 080805: Faulkes Telescope South optical observations

[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:  8076
SUBJECT: GRB 080805: Faulkes Telescope South optical observations
DATE:    08/08/06 20:03:48 GMT
FROM:    Cristiano Guidorzi at INAF-OAB  <cristiano.guidorzi at brera.inaf.it>

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

On 2008 August 05 (10:12:35 UT) we began observing the field of GRB 080805
(Pagani et al. GCN Circ. 8059) with the Faulkes Telescope South using
the R and i' filters.

In our coadded i' frame we marginally detect the optical afterglow
(Kruehler et al. GCN Circ. 8060; de Ugarte Postigo et al. GCN Circ. 8061):

Telescope   Filter  T_mid[hr]   Exposure[s]      Mag
-----------------------------------------------------------
FTS         i'         5.410       6x300       22.5 +/- 0.4
-----------------------------------------------------------

The calibration was performed using the I magnitudes of several
USNOB-1 catalogue field objects.
>From the comparison with the value reported by GROND
(Kruehler et al. GCN Circ. 8060) we estimate an average
power-law decay index of ~0.7, consistent with that inferred
in the R band (de Ugarte Postigo et al. GCN Circ. 8061).