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GCN Circular 6784

GRB 070913: SMARTS optical/IR observations
2007-09-13T02:08:48Z (17 years ago)
Bethany Cobb at Yale U <>
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 070913
(Markwardt et al. GCN 6782) with a mid-exposure time of
(2007-09-13 01:11 UT, ~34 minutes post-burst). Optical imaging in B,V,R
and I has a field of view of 6'x6' and, therefore, covers the entire GRB
error circle.  IR imaging in J, H, K and Y has a smaller field
of view and covers a region totalling 3 square arcminutes in
the middle of the quoted error region.  Several dithered images
were obtained in each filter, with total summed exposure times
of 180s in each of BRIYJK and 120s in each of H and V.

Preliminary visual comparison of the optical images to the DSS
and the IR images to 2MASS frames does not reveal any new sources
to a limiting magnitude of I>18.2 and J>15.8 (calibrated using USNO-B1.0 
and 2MASS stars).

[GCN OPS NOTE (13sep07): Per author's request, the following statement was added:
"Due to the recalculated BAT position position (#6785), the SMARTS observations
actually do not cover any of the GRB error region for this burst."]
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