GCN Circular 370
Subject
GRB 990704, optical observations
Date
1999-07-05T22:57:23Z (25 years ago)
From
Alan Diercks at U.Washington <diercks@astro.washington.edu>
Alan Diercks, Kevin Krisciunas, and Eric Deutsch (Univ. Washington)
report on behalf of the UW and LONEOS GRB collaborations:
The position of the possible optical counterpart to GRB 990704
reported by Maury et al. (GCN 363) (12:19:29.29 -03:47:25.8) was
imaged in the course of the LONEOS project approximately one month
ago, June 6, 1999. Three 60s, un-filtered CCD exposures were taken
with the 60cm Schmidt telescope. Combining these images, we detect
the object noted by Maury et al with an un-filtered magnitude of m =
19.6 +/- 0.3 relative to the "red" magnitude of USNO-A1.0 star
U0825_07735496. We measure the following unfiltered magnitudes for
three stars from the USNO-A1.0 Catalog:
USNO number RA(2000) DEC(2000) USNO UW/LONEOS
r_mag mag
U0825_07735496 12:19:33.74 -03:47:25.3 15.6 15.6 +/- 0.1 *calibrator*
U0825_07735738 12:19:36.43 -03:47:12.6 16.5 16.8 +/- 0.1
U0825_07735688 12:19:35.95 -03:46:32.9 16.5 16.7 +/- 0.1
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