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GCN Circular 14227

Subject
GRB 130215A: Additional P200 NIR observations
Date
2013-02-17T10:56:45Z (11 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.
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