[vsnet-grb-info 7425] GRB 090313: Faulkes Telescope North observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8989
SUBJECT: GRB 090313: Faulkes Telescope North observations
DATE:    09/03/13 18:53:56 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi at fe.infn.it>

C. Guidorzi (U. Ferrara), A. Melandri, I. A. Steele (Liverpool JMU),
A. Gomboc (U. Ljubljana), D. Bersier, C.J. Mottram, C.G.  Mundell,
R.J. Smith (Liverpool JMU), P. O'Brien, N. Bannister,
N. Tanvir (U. Leicester) on behalf of a large collaboration report:

The 2-m Faulkes Telescope North (Hawaii) automatically reacted to the
Swift burst GRB 090313 (trigger=346386, Mao et al. GCN 8980).

Observations started about 168 s after the trigger time with filters
BRi. We confirm the detection of the optical counterpart (Chornock et 
al. GCN 8979,
Updike et al. GCN 8983, Perley et al. GCN 8985).
The afterglow magnitude was observed to rise and peak around
1.3 ks post burst, followed by a rapid decay out to ~ 10 ks.
Further observations suggest a subsequent flattening.

Filter  Tmid(s)    Exposure(s)    Mag
------------------------------------------------
   R        880           60      16.12 +/- 0.07
   R       1260          120      15.60 +/- 0.05
   R      12290          300      18.20 +/- 0.20
------------------------------------------------

Magnitudes are calibrated with respect to the nearby USNOB1 star
13:13:35.789 +08:05:24.11 assuming its catalogue value of R2=17.08.
Further observations are going to be attempted.