GCN Circular 14227
Subject
GRB 130215A: Additional P200 NIR observations
Event
Date
2013-02-17T10:56:45Z (13 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley (Caltech) reports:
I re-observed the location of GRB 130215A with the Wide-Field Infrared
Camera (WIRC) on the Palomar 200-inch telescope on 2013-02-17 UT between
02:09 and 02:37 and between 04:29 and 04:56. Images were again taken in
J, H, and Ks-bands; transmission and seeing conditions were good.
The NIR afterglow remains well-detected in the most recent images.
Photometry of the Ks-band images gives the following magnitudes (Vega):
t_mid=48.75 hours : Ks = 17.57 +/- 0.05 mag
t_mid=51.07 hours : Ks = 17.60 +/- 0.07 mag
Relative to the previous night (GCN 14222), these observations show
remarkably little fading (decay index alpha~0.4 between 25-50 hours,
compared to alpha~1.5 earlier; Butler et al., GCN 14212). This could
indicate contribution from a bright host galaxy, but no obvious
extension of the source is seen (in 1" seeing). Alternatively it could
indicate a bump, plateau or flare in the light curve. Further
observations with WIRC are not planned, but observations elsewhere are
encouraged to constrain further evolution of the afterglow.