[vsnet-grb-info 5876] GRB080328: Faulkes Telescope North observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7526
SUBJECT: GRB080328: Faulkes Telescope North observations
DATE:    08/03/28 09:39:11 GMT
FROM:    Cristiano Guidorzi at INAF-OAB  <cristiano.guidorzi at brera.inaf.it>

C. Guidorzi (INAF-OAB),, A. Gomboc (U. Ljubljana), D. Bersier, C.G. 
Mundell, I.A. Steele, R.J. Smith, D. Carter, S. Kobayashi, M. Bode 
(Liverpool JMU), P. O'Brien, N. Bannister, N. Tanvir (U. Leicester) 
report:

The 2-m Faulkes North Telescope (Hawaii) automatically reacted to the
Swift burst GRB080328 (trigger=307931, Perri et al. GCN 7525).

Observations started about 167 s after the trigger time. We confirm
the detection of the optical counterpart by UVOT.

>From the first 3x10 s exposure frames in R, we estimate a temporal
decay index between 167 and 240 s after the trigger time of
alpha = 1.4 +/- 0.2.

Filter  Tstart(s)  Exposure(s)    Mag
-----------------------------------------------
    R       167           10      16.96 +/- 0.02
    R       198           10      17.26 +/- 0.02
    R       230           10      17.44 +/- 0.02
-----------------------------------------------

Magnitudes are calibrated with respect to USNOB1 R2 in the R filter.
A systematic error on absolute magnitudes of ~0.3 must be included.