1988 Fiscal Year Final Research Report Summary
MAGNETIC FIELDS AND ACTIVITY IN SPIRAL GALAXIES
| Project/Area Number |
61460009
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Astronomy
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| Research Institution | Institute of Astronomy, Faculty of Sci., University of Tokyo |
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Principal Investigator |
SOFUE Yoshiaki Fac. Sci., Univ. Tokyo, Prof., 理学部, 教授 (10022667)
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| Co-Investigator(Kenkyū-buntansha) |
HAYASHI Masahiko ibid, Res. Fel., 理学部, 助手 (10183914)
UCHIDA Yutaka Fac. Sci., Univ. Tokyo, Prof., 理学部, 教授 (90012814)
FUJIMOTO Mitsuaki Fac. Sci., Nagoya Univ., Prof., 理学部, 教授 (70022580)
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| Project Period (FY) |
1986 – 1988
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| Keywords | Galaxies / Our Galaxy / Magnetic fields / Activity / Galactic center / 磁場 / 電波観測 |
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| Research Abstract |
The structures of magnetic fields in spiral galaxies have been investigated on the basis of observations of linear polarization of galaxies. The large-scale field orientation in the majority of nearby spiral galaxies have been shown to be bisymmetric spiral. A few exceptions are M31 and IC342 that have ring or axi-symmetric field configurations.
The formation mechaniss of these field configurations were studied based on theoretical consideration of dymano mechanism. It has been suggested that the field was originated in a protogalactic stage by winding up a large-scale intergalactic magnetic field in to the galaxy. The spiral field in the disk plane is produced by the differential rotation of the galaxy and is maintained in a steady state due to the dynamo action. On the other hand, the vertical component is accumulated toward the galactic center with the accreting interstellar gas to yield a strong vertical magnetic field.
The spiral field was shown to act an important role in the formation of the spiral structure of a galaxy, in addition to the density wave mechanism. The vertical field in the galactic center was shown to be important to produce a large-scale ejection perpendicular to the disk plane, which makes a galaxy-scale jet. In fact our observations showed the presence of a galactic center jet of 10,000 light year length.
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