[AAVSO-HEN] GRB 071117: Gemini Optical Afterglow Discovery

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
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TITLE:   GCN CIRCULAR
NUMBER:  7110
SUBJECT: GRB 071117: Gemini Optical Afterglow Discovery
DATE:    07/11/19 04:17:43 GMT
FROM:    Josh Bloom at UC Berkeley  <jbloom at astron.berkeley.edu>

J. S. Bloom (UC Berkeley), on behalf of the Gemini GRB collaboration,  
reports:

"Starting at 2007 Nov 19 00h19m, deep r-band observations of the  
field of GRB 071117 (Ukwatta et al., GCN 7098) were obtained with  
Gemini (see Bloom, GCN 7105 for information about the first epoch).  
Image differencing reveals that source s2 (just outside the formal  
XRT error circle) is fading, and is the likely optical afterglow of  
the GRB. To reiterate the position:

   s2:   ra= 22:20:10.42  dec = -63:26:35.5 (J2000)

The uncertainty is 350 mas in each coordinate (relative to USNO  
B1.0). Further is analysis is ongoing."

A finder may be obtained at:
   http://lyra.berkeley.edu/~jbloom/grb071117-diff.pdf

We thank the expert Gemini staff for carrying out this ToO.

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