2005 Fiscal Year Final Research Report Summary
Theoretical Study of Physical Processes and Interactions in Large Scale Jets
| Project/Area Number |
16540215
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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, 大学院・理学研究科, 教授 (20154891)
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| Project Period (FY) |
2004 – 2005
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| Keywords | Relativistic Hydrodynamics / Particle Acceleration / Shock Waves / Radio Galaxies / Synchrotron Radiation / Compton Scattering / Electron Positron Pairs |
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| Research Abstract |
X-ray emission from large scale jets is interpreted as synchrotron emission for FR-I radio galaxies and inverse Compton scattering of CMB photons for FR-II galaxies, respectively. However, quantitative estimates of bulk Lorentz factor and magnetic field strength are largely affected by internal structure of jets. Detailed investigations on Cen-A jets are made to show that particle acceleration in the interaction region between jet surface and surroundings plays an important role. We proposed a reflection model for the orphan TeV flare observed for 1959+650, which also implies the importance of internal structure of jets.
We have also made the following researches on relevant physical processes.
1.Dynamical consideration of internal shocks indicates that the rest mass density of the jet matter is about thousand times larger than that of relativistic electrons.
2.Relativistic beaming effects on apparent structure on polarization and brightness map are not simple, which should be taken into account in the interpretation of observations.
3.Klein-Nishina effect in Compton scattering can largely modify the electron spectrum and in some cases it does not necessarily lead to a strong decrease of radiation intensity.
4.We discussed the formation mechanism and instability of electron-positron beams.
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