Transient X-Ray Burster KS 1731-260

R. Sunyaev and the Kvant Team report: "During observations of the GX 1+4 field on Aug. 16 the TTM instrument of the Mir-Kvant X-ray Observatory discovered a new transient x-ray burster at R.A. = 17h31m.1, Decl. = -26d03' (equinox 1950.0; uncertainty 1'). The persistent flux from this source in the 2-27-keV band varies from 50 to 90 mCrab, and a bremsstrahlung fit to the spectrum corresponds to temperature kT = 5 keV. During subsequent observations on Aug. 20-21 the source was also bright. Several outbursts of duration less than 15 s and averaged peak flux up to 0.6 Crab were detected during Aug. 16-21. Further analysis has revealed this source in a lower state during observations of the galactic center region on 1988 Oct. 21, the 2-27-keV flux then being 25 mCrab."