| Project/Area Number |
18540239
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | Osaka University |
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Principal Investigator |
TAKAHARA Fumio Osaka University, Graduate School of Science, Professor (20154891)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥2,370,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥270,000)
Fiscal Year 2007: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2006: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Radio Galaxies / Relativistic Jets / Synchrotron Radiation / Polarization / Particle Acceleration / Quasars / Collisionless Shock / Plasma Instabilities / コンプトン散乱 |
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| Research Abstract |
(1) We proposed a model in which inhomogeneities in the jet cause light echoes accompanying primary flares, which may explain orphan TeV flares observed for several TeV blazers.
(2) Apparent structures of relativistic jets depend complicatedly on the lateral and transverse structure and on the way of time variation because the difference between the matter velocities and light propagation velocity is very small. We showed that observed spatial offsets among X-ray, optical and radio peaks can be explained by energy dependent cooling time of accelerated electrons in a propagating emitting blob.
(3) Effects of the relativistic aberration and beaming on the polarization structure are analyzed. We clarified that the observed polarization angle is perpendicular to the magnetic field direction on the sky plane in the comoving frame. Based on this we studied statistical properties of the polarization angle distribution. The magnetic field turns out to be predominantly directed in the transverse direction in the comoving frame. We also studied polarization properties of perturbed helical field geometry.
(4) Electron acceleration process for collisionless shocks are investigated. We showed that contrary to the one-dimensional case, no surfing acceleration occurs for two-dimensional case. Plasma instabilities in the existence of ion beams are also considered for two-dimensional case and ion two-stream instability turns out to be the most unstable mode.
(5) Two relativistic fluids in a relative motion are considered and energy and momentum exchange rates between them are calculated and interpolation formulas were proposed. Using them we performed numerical simulations of the formation of jets.
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