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GCN Circular 13586

GRB 120804A: Gemini-North observations
2012-08-05T05:57:28Z (12 years ago)
Ryan Chornock at Harvard <>
R. Chornock and E. Berger (Harvard) report on behalf of a larger 

We observed the position of the X-ray afterglow of the short GRB 120804A 
(Lien et al., GCN 13573) using GMOS on the Gemini-North 8-m telescope. 
Observations began at 05:47 UT on 2012 August 4 (approximately 4.9 hours 
after the BAT trigger).  We obtained 11x180s of observations in both the 
r and i filters.  We find a pair of faint sources in the i band 
observations within the enhanced XRT position (Osborne et al., GCN 
13577) with coordinates (J2000):

S1:  15:35:47.48, -28:46:56.2
S2:  15:35:47.53, -28:46:57.6

with astrometric errors of about 0.3" relative to 2MASS.  S1 is slightly 
brighter than S2 in i.  Neither source is detected in r.  Further 
observations are planned in order to search for variability of these 

We thank the Gemini staff, particularly Chad Trujillo, for their 
assistance with these observations.
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