Discovery of a Slow X-Ray Pulsator, AX J1740.1-2847, in the Galactic Center Region

We report the discovery of an X-ray pulsar AX J1740.1-2847 from the Galacticcenter region. This source was found as a faint hard X-ray object on 7--8 September 1998 with the ASCA Galactic center survey observation. Then,coherent pulsations of P=729 +/- 14 sec period were detected. The X-ray spectrum is described by a flat power-law of ~= 0.7 photon index. Thelarge absorption column of log NH ~= 22.4 (cm^-2) indicates that AX J1740.1-2847 is a distant source, larger than 2.4kpc, and possibly near at the Galactic center region. The luminosity in the2--10 keV band is larger than 2.5 x 10^33 erg/s, or likely to be 3.2 x 10^34erg/s at the Galactic center distance. Although the slow pulse period does notdiscriminate whether AX J1740.1-2847 is a white dwarf or neutron star binary,the flat power-law and moderate luminosity strongly favor a neutron starbinary.