XTE J1859+226
Abstract
P. M. Garnavich and K. Z. Stanek, Harvard-Smithsonian Center for Astrophysics; and P. Berlind, Fred L. Whipple Observatory (FLWO), report the detection of an optical counterpart to the new x-ray transient XTE J1859+226. CCD images taken on Oct. 12.07 UT with the FLWO 1.2-m telescope show a bright stellar object not seen on the second Palomar Sky Survey. The exact position based on the HST Guide Star Catalog is R.A. = 18h58m41s.58, Decl. = +22o39'29".4 (equinox 2000.0; estimated uncertainty 0".5). This is just to the east of the x-ray error circle given on IAUC 7274 and about 80" north of a 10th-mag star. The brightness of the optical transient is estimated to be R = 15.1, and it appears blue compared to other stars in the field. Images taken over a 3.3-hr span show < 0.05 mag variation in brightness. A faint object (mag about 21) is visible on the Sky Survey within 1" of the position of the transient. The spectrum obtained with the FLWO 1.5-m telescope on Oct. 12.22 displays a strong blue continuum with weak emission lines. H-alpha, with an equivalent width of 0.54 nm, and a velocity width of 1200 km/s (FWHM), is seen. He II 468.6-nm is 3 times stronger than H-beta and blended with permitted C III and N III. The spectrum is consistent with an x-ray nova in outburst. A finder chart may be found at http://cfa-www.harvard.edu/~peterg/gosox/j1859.jpg.
- Publication:
-
International Astronomical Union Circular
- Pub Date:
- October 1999
- Bibcode:
- 1999IAUC.7276....1G