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The origin of the Galactic center diffuse X-ray emission investigated by near-infrared imaging and polarimetric observations

Published online by Cambridge University Press:  22 May 2014

Shogo Nishiyama
Affiliation:
National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan email: shogo.nishiyama@nao.ac.jp
Kazuki Yasui
Affiliation:
Department of Astronomy, Kyoto University, Kyoto 606-8502, Japan
Tetsuya Nagata
Affiliation:
Department of Astronomy, Kyoto University, Kyoto 606-8502, Japan
Tatsuhito Yoshikawa
Affiliation:
Department of Astronomy, Kyoto University, Kyoto 606-8502, Japan
Hideki Uchiyama
Affiliation:
Science Education, Faculty of Education, Shizuoka University, Shizuoka 422-8529, Japan
Motohide Tamura
Affiliation:
National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan email: shogo.nishiyama@nao.ac.jp
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Abstract

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The origin of the Galactic center diffuse X-ray emission (GCDX) is still under intense investigation. We have found a clear excess in a longitudinal GCDX profile over a stellar number density profile in the nuclear bulge region, suggesting a significant contribution of diffuse, interstellar hot plasma to the GCDX. We have estimated that contributions of an old stellar population to the GCDX are ∼50% and ∼20% in the nuclear stellar disk and nuclear star cluster, respectively. Our near-infrared polarimetric observations show that the GCDX region is permeated by a large scale, toroidal magnetic field. Together with observed magnetic field strengths in nearly energy equipartition, the interstellar hot plasma could be confined by the toroidal magnetic field.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2014 

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