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GCN Circular 387

Subject
GRB 990712
Date
1999-07-12T23:07:26Z (25 years ago)
From
Kailash C. Sahu at STSci <ksahu@stsci.edu>
Gaspar Bakos (STScI and Konkoly Observatory), Kailash Sahu (STScI) and 
John Menzies (SAAO) observing on behalf of the PLANET collaboration, and 
Paul Vreeswijk (Univ. Amsterdam) and Filippo Frontera (ITESE, CNR, Bologna)
on behalf of the Amsterdam/Beppo-SAX-Bologna  GRB follow-up team report: 
GRB 990712 WFC error circle (Frontera et al. GCN #385) was observed with the 
1m telescope of the South African Astronomical Observatory at Sutherland 
on July 12.87 UT in R filter with an integration time of 900 sec. Comparison 
with the Digitized Sky Survey (DSS) image shows a relatively bright source 
at RA (2000) = 22 31 53.1, Dec (2000) = -73d 24' 29" (with a positional
uncertainty of about 1 arcsec) which is absent in the DSS image. Based on 
the red magnitudes of thee USNO stars in the field,  the estimated magnitude 
of the new source is R = 17.85 +/- 0.2. Since the limiting magnitude of the 
DSS image is at least 21, the new source is most likely the optical counterpart
of GRB 990712. Further observations are urged. A finding chart of the 
optical counterpart can be seen at http://www.stsci.edu/~ksahu/grb990712.
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