GCN Circular 16180
Subject
GRB 140428A: Keck detection of a red optical afterglow candidate
Event
Date
2014-04-29T07:23:15Z (12 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley (Caltech) reports:
I observed the position of GRB 140428A (Kocevski et al., GCN 16177; Page
et al., GCN 16178) using LRIS on the Keck I 10-meter telescope. A
single 150-second imaging exposure was acquired simultaneously in both g
and i filters. An faint source is well-detected inside the XRT error
circle in the i-band image at the following location (J2000):
RA = 12:57:28.392
dec = +28:23:06.28
However, the object is completely absent in g-band. Photometry relative
to SDSS gives magnitudes of:
g > 26.42
i = 23.55 +/- 0.07
at a time of 06:09:30 UT (2014-04-29), 7.478 hours after the GRB trigger.
If this corresponds to the afterglow of the GRB, the red color suggests
either a (moderately) high-redshift or dust-extinguished event. Further
observations are planned.