S. C. Odewahn, J. S. Bloom, and S. R. Kulkarni, California Institute of Technology, report on behalf of the Caltech-NRAO-CARA GRB Collaboration: "On Jan. 23.56 UT, we imaged the BeppoSAX localization (Piro et al. 1999, GCN 199, http://gcn.gsfc.nasa.gov/gcn/gcn3/199.gcn3) of GRB 990123 with the Palomar 1.52-m reflector (+ CCD). We found a source (R = 18.2) located at R.A. = 15h25m30s.5, Decl. = +44o46'00" (equinox 2000.0; GCN 202 gives a revised BeppoSAX position of R.A. = 15h25m29s, Decl. = +44o45'.5). The error in the position (derived from the Digital Sky Survey) is about 1".5. At the same location, no object is detected to the plate limit of the first Palomar Sky Survey, whereas a faint (R about 21.3) object is seen in the second Palomar Sky Survey image. The photometry is preliminary and is based on the Cambridge Automated Plate Machine catalogue. Finding charts can be found at http://astro.caltech.edu/~jsb/GRB/grb990123.html; see also GCN 201. We suggest that the bright object is the optical afterglow of GRB 990123 and that the faint object is the host galaxy. If so, this is the brightest optical afterglow and host galaxy known to date. In view of this, we urge observations at all wavelengths and particularly spectroscopic observations of this object."
International Astronomical Union Circular
- Pub Date:
- January 1999