Theoretical Foundation for Observational Cosmology
| Project/Area Number |
01540226
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
核・宇宙線・素粒子
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| Research Institution | Hirosaki University |
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Principal Investigator |
FUTAMASE Toshifumi Hirosaki Univ. Fac. of Science, Professor, 理学部, 教授 (20209141)
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| Co-Investigator(Kenkyū-buntansha) |
KASAI Masumi Hirosaki Univ. Fac. of Science, Lecturer, 理学部, 講師 (30204358)
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| Project Period (FY) |
1989 – 1990
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1990: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1989: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Global structure / Inhomogeneity / General Relativity / Spatial averaging / Distance-redshift / Gravitational lenses / 減宙の大域的構造 / 距離一赤方偏移関係 / 非一様宇宙 / ポスト・ニュ-トン近似 / 距離-赤方偏移関係 |
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| Research Abstract |
Global structure of the universe is described by the Robertson-Walker spacetime. However the real universe has inhomogeneities in various scales. It has been a long-standing problem how these inhomogeneities may be described in the framework of general relativity. Our research solves this problem by introducing the spatial averaging process and applying the post-Newtonian approximation. This provides the first approximation scheme for constructing the metric of realistic universe.
Using this scheme we investigated the propagation of light rays and uncertainties in the definition of the distance-redshift relation which has the fundamental importance in the observational cosmology. We also investigated numerically how local inhomogeneities affect the propagation of light rays. g to these studies it is shown that the distance usually used in the literature is not always appropriate in certain situations.
We also studied gravitational lenses and proposed a new method to determine the cosmological constant.
The density parameter is one of the most important parameters to determine the global structure of the universe. We obtained a relation between the density parameter and the peculiar velocity of galaxies in highly nonlinear region for an one-dimensional density distribution.
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Report
(3 results)
Research Products
(23 results)
