GCN Circular 16884
Subject
GRB 141005A: P60 probable afterglow deteaction
Date
2014-10-05T06:53:57Z (10 years ago)
From
Daniel Perley at Caltech <dperley@astro.caltech.edu>
D. A. Perley (Caltech) reports on behalf of a larger collaboration:
The Palomar 60-inch robotic telescope automatically triggered on the
Swift-BAT alert for GRB 141005A (GCN 16882, D'Elia et al.) and began
observations of the field at 05:16:28 UT, 202 seconds after the BAT
trigger. A sequence of cycling 60-second r, i, and z band images were
acquired, ending at 05:33:20 UT.
In the initial images we identify a source inside the SPER XRT error
circle at the following position:
RA = 19:24:22.392
dec = +36:05:42.26
(J2000, +/- 0.3")
The source is faint and probably fading, from r = 20.6 +/- 0.2 and i =
20.0 +/- 0.2 in the initial exposures to r = 21.4 +/- 0.3 and i = 21.3
+/- 0.4 in the final exposures. The source is also present in archival
imaging of the field from SDSS. Measuring the flux of the source in the
same aperture in these images yields magnitudes of g=21.9, r=21.6,
i=21.3, z=20.7.
These observations suggest a faint optical afterglow superimposed on a
host galaxy or Galactic foreground star. More observations are
encouraged to characterize this object.