J. Zhu and H. T. Zhang, on behalf of the Beijing Astronomical Observatory (BAO) GRB team, write: "R-band images of the BeppoSAX WFC error circle of GRB 990123 were obtained on Jan. 23.756 UT (8.5 hr after the GRB) with the BAO 0.6-m Schmidt telescope at Xinglong. Due to bad weather, only one 20-min exposure image taken in thin cloud was usable (FWHM = 6"). The central part of the image is posted at http://vega.bac.pku.edu.cn/~zj/grb/grb990123.gif. A faint object could be seen close to the optical candidate position suggested by S. C. Odewahn et al. (IAUC 7094); its position from our measurement is R.A. = 15h25m30s.28, Decl. = +44o45'59".0 (1-sigma = 0".5), with a magnitude of 19.2 (+/- 0.5?) from four stars in the USNO-A V1.0 catalogue. The object in our image seems slightly extended and slightly to the southwest, compared with the discovery image of Odewahn et al., but it seems to be impossible to confirm from only one image of poor quality. However, it could be concluded that if such an object (in our image) is not real, the optical transient in Odewahn et al.'s images must have faded greatly during the 4.6-hr interval."
International Astronomical Union Circular
- Pub Date:
- January 1999