GCN Circular 9809
Subject
GRB090814A: NOT optical follow-ups
Event
Date
2009-08-14T23:02:39Z (16 years ago)
From
Dong Xu at DARK,NBI <dong@astro.ku.dk>
D. Xu, J.P.U. Fynbo (DARK/NBI), P. Jakobsson (Univ. Iceland), Tiina
Liimets (NOT) report on behalf of a larger collaboration:
We observed the field of GRB 090814A (Ukwatta et al. GCN 9793; Updike et
al., GCN 9794) with the Nordic Optical Telescope equipped with ALFOSC.
We obtained 3x600 s R-band frames staring on August 14th, 21:15:11 UT,
20.38 hr after the burst.
The optical afterglow is clearly detected in each frame. The magnitude
is R~22.4 calibrated against the reference star, #1156-0231252 with
R2=19.25, of the USNO B1 catalog.
Compared with the previous measurement of R~21.5 around 70 mins after
the burst (Jakobsson et al., GCN 9797), the afterglow is decaying quite
shallowly, with a power-law slope of ~0.3, being consistent with the
X-ray decaying law during the same period (Page & Ukwatta, GCN 9801).