GCN Circular 17584
Subject
GRB 150314A: P60 observations
Date
2015-03-15T01:06:49Z (9 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley (Caltech) and S. B. Cenko (NASA/GSFC) report:
The Palomar 60-inch robotic telescope began automatic follow-up of the
location of GRB 150314A (Hagen et al., GCN 17573) at 05:08:40 UT on
2015-03-14, 13.4 minutes after the GRB trigger. A sequence of
60-second r, i, and z exposures were acquired, lasting until 06:36 UT.
Another sequence of 180-second g, r, and i exposures was taken between
09:01 UT and 10:54 UT.
We detect the optical afterglow reported by Zheng and Filippenko (GCN
17574) in individual exposures from the early sequence as well as in a
stack of the later-time exposures. Calibrating to a nearby USNO star
(RA=126.701423, dec=63.829609, R2=15.33) gives the following photometry:
t_med = 834s : R = 18.59 +/- 0.05
t_med = 1179s : R = 18.96 +/- 0.05
t_med = 1437s : R = 19.06 +/- 0.07
t_med = 1693s : R = 19.41 +/- 0.07
t_med = 1977s : R = 19.59 +/- 0.08
t_med = 18365s : R = 21.73 +/- 0.13
The afterglow fades as approximately t^-0.9 throughout our observations.