PROPERTIES OF THE PULSAR GX-301-2 IN THE HARD X-RAY RANGE

In 1993-1994, we performed a series of observations of the X-ray pulsa r GX 301-2 with the HEXE instrument of the Mir-Kvant Observatory. We m easured the period of the source (it varied between 675 and 678 s) and constructed the pulse profiles in various bands of the energy range 2 0-75 keV. The measured 20-100-keV luminosity varied between 8 x 10(34) and 7 x 10(35)d(2) erg s(-1) (for a point source at distance d kpc). The observed spectrum can be described quite satisfactorily by the ''c anonical'' model for X-ray pulsars with gamma = 1.3, E-c similar to 23 keV, and E-f similar to 9 keV.The spectrum changed little from measur ement to measurement, but at maximum light, it was slightly softer tha n that in all the other states. We detected significant variations of the hardness with pulse phase, but the accumulated data were not enoug h to study the related variations in the spectral parameters. The spec trum exhibited no statistically significant traces of cyclotron lines. The interpretation of the pulse profiles in terms of the model of a r otating neutron star with two emitting polar caps that includes gravit ational effects indicates that the most probable inclination of the pu lsar's magnetic axis with respect to its spin axis is 40 degrees-70 de grees, and that the angle between the observer's direction and the spi n axis is similar to 75 degrees-85 degrees.