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GCN Circular 226

GRB 990123 Optical Follow-Up
1999-01-26T01:01:29Z (25 years ago)
Jin Zhu at Beijing Obs <>
GRB 990123 Optical Follow-Up

J. Zhu, J. S. Chen, and H. T. Zhang, on behalf of the Beijing Astronomical
Observatory GRB team report:

"We observed the GRB 990123 OT (GCN #202) around Jan. 25.9 with
BAO 0.6-m Schmidt telescope under good weather. One 40-min. exposure
was made with BATC band-i filter and the very weak source at RA=15:25:30.35,
Dec=44:45:59.4 (J2000) was detected near the detection limit of the image
which gives a magnitude of 21.3 +/- 0.3 (Jan 25.901) using the No. 1 and
No. 2 stars in GCN #204. Assuming a minimum decay slope of 1.18 (for the
OT) obtained from our previous observations (GCN #217), we conclude that
the source we detect here is probably the coincident galaxy found on
the digital POSS-II image by Odewahn et al. (GCN #201 and IAUC 7094).

This report may be cited."
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