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GCN Circular 6147

Subject
GRB 070224: WHT K-band imaging
Date
2007-02-25T11:08:53Z (17 years ago)
From
Nial Tanvir at IofA U.Cambridge <nrt@ast.cam.ac.uk>
E. Rol, N.R. Tanvir, R. Starling (U. Leicester) and P. Groot
(U. Nijmegen) report on behalf of a larger collaboration:

We observed the field of GRB 070224 with the WHT/LIRIS instrument
in poor seeing, beginning at Feb 24 23:06 UT.  Our 6 minute K-band
image reached a 3-sigma limit of K~19.2 (based on calibration via
four 2MASS stars in the field).

A later observation in better seeing, beginning at Feb 25 04:44 UT,
reached a limiting magnitude of K~19.7.

In both images within the XRT error circle (GCN 6143) we see a source
at the position of the candidate reported by Thoene et al. (GCN 6142),
with a magnitude that is consistent with K~19.2 in both cases,
although some fading can't be ruled out.

In the second image we also see (close to the limit) another source
with (2000) coordinates approximately:

 11 56 06.26   -13 19 50.0
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