Ohashi, T.,
Inoue, H.,
河合 誠之,
Koyama, K.,
Matsuoka, M.,
Mitani, K.,
Tanaka, Y.,
Nagase, F.,
Nakagawa, M.,
Kondo, Y..
English:
Ohashi, T.,
Inoue, H.,
Kawai, N.,
Koyama, K.,
Matsuoka, M.,
Mitani, K.,
Tanaka, Y.,
Nagase, F.,
Nakagawa, M.,
Kondo, Y..
Language
English
Journal/Book name
Japanese:
English:
Publications of the Astronomical Society of Japan
Volume, Number, Page
Vol. 36
pp. 719-729
Published date
1984
Publisher
Japanese:
English:
Conference name
Japanese:
English:
Conference site
Japanese:
English:
Abstract
Her X-1 was observed during an on-state of the 35-d cycle in May 1983 with the gas scintillation proportional counters on board Tenma. The declining phase of the on-state is characterized by two progressive features: (1) decrease of the main pulse amplitude, and at the same time (2) increase of absorption column of relatively cool matter. However, the photoelectric absorption in this cool medium does not explain the feature of the main pulse decrease which occurs at all energies. The spectral shape after the correction for photoelectric absorption is found to remain essentially the same through the main-pulse decrease. This may be interpreted as due to an attenuation of X-ray beam by electron scatterings in a highly ionized plasma at an estimated distance of ≡3×108cm from the neutron star.