A SEARCH FOR CYCLOTRON RESONANCE FEATURES WITH INTEGRAL

摘要

We present an INTEGRA L observation of the Cen-Crux region in order to search the electron cyclotron resonance scattering features from the X-ray binary pulsars. During the AO1 200 ks observation, we clearly detected 4 bright X-ray binaries, 1 Seyfert Galaxy, and 4 new sources in the field of view. Especially from GX301-2, the cyclotron resonance feature is detected at about ～ 37 keV, and width of 3-4 keV. In addition, the depth of the resonance feature strongly depends on the X-ray luminosity. This is the first detection of luminosity dependence of the resonance depth. The well-known twin pulsars are spatially separated by JEM-X and IBIS/ISGRI, and pulse periods are measured individually; 296.90 sec for 1E1145-6141 and 292.5 sec for 4U1145-619. The cyclotron resonance feature is marginally detected from 1E1145.1-6141. Cen X-3 was very dim during the observation and poor statistics disable us to detect the resonance features.