GCN Circular 9779
Subject
GRB 090812: Faulkes Telescope South Continued Optical Monitoring
Date
2009-08-12T18:02:44Z (15 years ago)
From
Zach Cano at ARI/John Moores Liverpool <zec@astro.livjm.ac.uk>
Z. Cano (Liverpool JMU), C. Guidorzi (U. Ferrara), C. Mundell, R.J. Smith,
D. Bersier, A. Melandri, I.A. Steele, S. Kobayashi, C.J. Mottram,
(Liverpool JMU), A. Gomboc (U. Ljubljana) report, on behalf of a large
collaboration:
Following our report of observations on the Liverpool Telescope (Smith et
al. GCN 9520) we continued monitoring the field of GRB090812 (Swift
trigger 359711, Stamatikos et al. GCN 9768) on the Faulkes Telescope South
(Australia) from 5.88 hours to 8.40 hours post burst in r' and i' bands.
We find from 6 x 300s stacked images:
t_exp filter t-T0 R-mag
----------------------------------------------------------
30min i' 5.88 hours 22.43 +/- 0.25
30min i' 8.40 hours 22.85 +/- 0.25
30min r' 6.60 hours 22.31 +/- 0.09
----------------------------------------------------------
The calibration is still preliminary and determined against stars in
the sdss field.
Finally, we find the decay rate in i' from 111s to 2.35ks post burst is
consistent with alpha ~ 1.25 +/- 0.1