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

In 1993-1994 a series of observations of the X-ray pulsar GX 301-2 by HEXE onboard Mir-Kvant was made. A period of pulsations was measured (it varied between 675 and 678 s) and pulse profiles in different energy bands were produced. The measured luminosity in the 20-100 keV energy range c hanged substantially between 8×10 34 and 7 ×10 35 d 2 erg/s (d is the distance to the source in kpc). The obtained spectrum is quite satisfactory described by the “canonical model for X-ray pulsars” with γ=1.3, Ec~23 keV, Ef~9 keV. It changed weakly between the observations, but was softest at brightness maximum. Significant variations of the spectral hardness over the pulse phase were detected, but t he acc umulated d ata a re insufficient to quantify variations in spectral parameters. No significant traces of cyclotron lines were found. An interpretation of the pulse profiles as superposition of emissions from two flat polar caps (with inclusion of gravitational lensing) leads to an estimate of the angle between the magnetic axis and axis of rotation of 40-70° and an angle between the direction to the observer and the rotation axis of 75-85 °.