[vsnet-grb-info 4360] GRB070224: Gemini Imaging Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6145
SUBJECT: GRB070224: Gemini Imaging Observations
DATE:    07/02/25 07:55:51 GMT
FROM:    Hsiao-Wen Chen at U Chicago  <hchen at oddjob.uchicago.edu>

H.-W. Chen (U Chicago), K. Glazebrook (Swinburne University), and J. S. 
Bloom (UC Berkeley) report on behalf of a larger collaboration:

"We obtained 2x900 sec dithered exposures of the field around GRB070224
(Racusin et al., GCN 6137), using GMOS and an i' filter on the Gemini
south telescope.  The observations started at Feb 25.102 UT, ~ 6 hours
after the initial Swift trigger.  We continued the observations with
2x900 sec dithered exposures in the z'-band, starting at Feb 25.125 UT.
Within the refined XRT position (Racusin et al., GCN 6143), we detect a
compact source at RA(J2000)=11:56:06.6 and Dec(J2000)=-13:19:48.9 (+/-
350 mas relative to USNO B1.0) that shows no apparent changes in the
brightness between two exposures of 15 min apart.  We note the presence
of extremely faint (~2 sigma) source at RA(J2000)=11:56:06.5 and
Dec(J2000)=-13:19:49.9 in the first i'-band exposure.  Further analysis is
underway."