GCN Circular 17191
Subject
GRB 141121A: Keck observations
Event
Date
2014-12-18T12:15:16Z (11 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley (Caltech) reports:
I observed the location of GRB 141121A (Lien et al., GCN
17075) using the imaging mode of the Low-Resolution Imaging
Spectrometer (LRIS) on the Keck I 10-meter telescope between 10:55 and
11:16 UT on 2014-12-18. A short sequence of exposures in g, R, and
i-bands was acquired.
The optical counterpart (Tanga et al., GCN 17078) is clearly detected in
all filters. Calibrating relative to SDSS, the magnitude is:
i = 23.96 +/- 0.07 (t = 27.3 days)
This measurement is significantly fainter than that reported by Toy et
al. based on DCT observations on 2014-12-07, and the counterpart appears
point-like in 0.8-arcsecond seeing. This suggests that the light is
still dominated by the afterglow.