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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 ,
Kazuki Yasui ,
Tetsuya Nagata ,
Tatsuhito Yoshikawa ,
Hideki Uchiyama  and
Motohide Tamura
Shogo Nishiyama
Affiliation:
National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588, Japan email: [email protected]
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: [email protected]
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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.

Keywords

Galaxy: centermagnetic fieldspolarization
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 9 , Symposium S303: The Galactic Center: Feeding and Feedback in a Normal Galactic Nucleus , October 2013 , pp. 449 - 453
Copyright
Copyright © International Astronomical Union 2014 

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