GRS 1737-31

R. Sunyaev, E. Churazov, M. Revnivtsev and S. Trudolyubov, Space Research Institute, Moscow, and Max Planck Institute for Astrophysics, Garching, report for M. Vargas, J. Paul, J.-P. Roques, E. Jourdain and the GRANAT/SIGMA Team: "Since Mar. 14 GRANAT has been observing the Galactic Center region. Preliminary analysis of SIGMA hard x-ray images revealed a new source in Scorpius at R.A. = 17h36m.7, Decl. = -30d57' (equinox 1950.0, error +/- 3 arcmin), 2.4 deg from the Galactic Center, at flux levels of 90 +/- 16 and 130 +/- 20 mCrab in the 35-75-keV and 75-150-keV bands, respectively. The photon index of the spectrum in this energy range is 1.6 +/- 0.3. Assuming a distance of 8.5 kpc for the source, the hard x-ray luminosity is about 10**37 erg/s. The source was detected at practically the same flux level on Mar. 14.23-15.59, 18.68-19.65 and 19.79-20.69 UT. The spectrum hardness suggests that this source is a distant x-ray nova and black-hole candidate."