GCN Circular 8711
Subject
GRB 081221: Probable host galaxy in Keck imaging
Date
2008-12-23T11:23:47Z (15 years ago)
From
Daniel Perley at U.C. Berkeley <dperley@astro.berkeley.edu>
D. A. Perley, J. S. Bloom (UC Berkeley), J. Kalirai (STSCI), R.
Strickler, E. Ramirez-Ruiz (UCSC), and A. A. Miller (UCB) report:
We began a series of deep optical imaging exposures on the field of GRB
081221 (Hoversten et al., GCN 8687) using the Keck I telescope (+LRIS)
starting at 2008-12-23 at 5:06 UT. We acquired 10x330s in g-band and
10x300s in I-band (simultaneously using the 560 dichroic).
A extended source coincident with the Gemini (Tanvir et al., GCN 8698)
and Swift XRT (GCN 8690) afterglow positions is clearly detected in our
g-band stack, which we tentatively identify as the host galaxy. The
magnitude within a 1.0" aperture of this object is approximately B~25.4
(calibrated relative to the USNO star at RA=15.797098, dec=-24.412259,
B2=19.59). It is only marginally detected in the I-band imaging, with
an estimated magnitude of I~24.5, though photometry in this band is
complicated by blending with a nearby object.
The detection of a host galaxy would be consistent with a low-redshift
origin (GCN 8698). Within the significant uncertainties of the
photometric calibration the color of the galaxy appears typical of
normal GRB hosts. Further analysis is planned.
An image of the field is posted to:
http://lyra.berkeley.edu/~dperley/081221/081221hostkeck.png
