[vsnet-grb-info 4127] GRB 061217, SMARTS optical observations

GCN Circulars gcncirc at capella.gsfc.nasa.gov
Mon Dec 18 08:40:16 JST 2006


TITLE:   GCN CIRCULAR
NUMBER:  5935
SUBJECT: GRB 061217, SMARTS optical observations
DATE:    06/12/17 23:40:08 GMT
FROM:    Bethany Cobb at Yale U  <cobb at astro.yale.edu>

B. E. Cobb (Yale), part of the larger SMARTS consortium, reports:

Using the ANDICAM instrument on the 1.3m telescope at CTIO, we
obtained optical/IR imaging of the error region of GRB 061217
(GCN 5926, Barthelmy et al.) with a mid-exposure time of
2006-12-17 05:50:32 UT, which is ~2.2 hours post-burst.
Total summed exposure times amounted to 15 minutes in I and V and
12 minutes in J and K. Unfortunately, our images were
centered on the initial BAT GRB coordinates, so that the position
of the X-ray afterglow (GCN 5932, Evans et al.) was not covered
by our IR imaging.

In the X-ray afterglow error region, no new source is detected in
either our I or V-band images to limiting magnitudes of I<21.5
and V<22 (calibrated against USNO-B1.0 stars).

No bright galaxy candidates are detected within about 20 arcsecond
of the X-ray afterglow.  The following four stellar-profile sources 
are detected in that area:
RA = 10:41:37.96, Dec = -21:07:31.93 (USNO-B1.0 0688-0249429)
RA = 10:41:37.64, Dec = -21:07:52.57 (USNO-B1.0 0688-0249427)
RA = 10:41:39.65, Dec = -21:07:35.52 (USNO-B1.0 0688-0249436)
RA = 10:41:39.75, Dec = -21:07:40.75

There are also 2 very dim sources in that 20 arcsecond radius area:
RA = 10:41:39.17, Dec = -21:07:32.77
RA = 10:41:37.01, Dec = -21:07:35.13
These might be galaxies, but their nature is unclear
since they are detected just at the limit of our imaging.




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