THE NEW AM HERCULIS-TYPE OBJECT AX J2315-592 DISCOVERED WITH ASCA

The new AM Her-type object AX J2315-592 was discovered with ASCA durin g the observation of IRAS 23128-5919. The light curve shows a clear pe riodic modulation at 1.489 +/- 0.013 hr. Follow-up phase-resolved opti cal spectroscopy confirmed coincidence of the rotational period of the white dwarf and the orbital period and identified AX J2315-592 as a n ew AM Her-type object. The shape of the X-ray light curve is quasi-sin usoidal, the amplitude of which decreases with increasing X-ray energy , which is the property of intermediate polars. The X-ray emission at the maximum of the folded light curve has an optically thin thermal pl asma emission spectrum with a temperature of 17 +/- 4 keV with negligi ble absorption. The spectrum at the minimum, on the other hand, suffer s from complex absorption. The X-ray light curve and the spectral char acteristics indicate that a single accreting pole is always within the visible hemisphere of the white dwarf, and the rotational minimum occ urs when the pole points toward the observer.