翻訳と辞書 Words near each other ・ Gravitational anomaly ・ Gravitational binding energy ・ Gravitational biology ・ Gravitational collapse ・ Gravitational compression ・ Gravitational constant ・ Gravitational coupling constant ・ Gravitational energy ・ Gravitational field ・ Gravitational Forces ・ Gravitational instability ・ Gravitational instanton ・ Gravitational interaction of antimatter ・ Gravitational keyhole ・ Gravitational lens ・ Gravitational lensing formalism ・ Gravitational metric system ・ Gravitational microlensing ・ Gravitational mirage ・ Gravitational plane wave ・ Gravitational potential ・ Gravitational Pull vs. the Desire for an Aquatic Life ・ Gravitational redshift ・ Gravitational shielding ・ Gravitational singularity ・ Gravitational soliton ・ Gravitational Systems ・ Gravitational time dilation ・ Gravitational two-body problem ・ Gravitational wave Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Gravitational lensing formalism ： ウィキペディア英語版 Gravitational lensing formalism (詳細はgeneral relativity, a point mass deflects a light ray with impact parameter $b~$ by an angle approximately equal to $\backslash hat\; =\; \backslash frac$ where G is the gravitational constant, M the mass of the deflecting object and c the speed of light. A naive application of Newtonian gravity can yield exactly half this value, where the light ray is assumed as a massed particle and scattered by the gravitational potential well. This approximation is good when $4GM/c^2b$ is small. In situations where general relativity can be approximated by linearized gravity, the deflection due to a spatially extended mass can be written simply as a vector sum over point masses. In the continuum limit, this becomes an integral over the density $\backslash rho~$, and if the deflection is small we can approximate the gravitational potential along the deflected trajectory by the potential along the undeflected trajectory, as in the Born approximation in quantum mechanics. The deflection is then $\backslash vec)=\backslash frac\; \backslash int\; d^2\backslash xi^\; \backslash int\; dz\; \backslash rho(\backslash vec^,z)\; \backslash frac|^2\},\; ~\; \backslash vec\; \backslash equiv\; \backslash vec\; -\; \backslash vec$ is the vector impact parameter of the actual ray path from the infinitesimal mass $d^2\backslash xi^\; dz\backslash rho(\backslash vec^,z)$ located at the coordinates $(\backslash vec^,\; z)$. == Thin lens approximation == In the limit of a "thin lens", where the distances between the source, lens, and observer are much larger than the size of the lens (this is almost always true for astronomical objects), we can define the projected mass density $\backslash Sigma(\backslash vec)=\backslash int\; \backslash rho(\backslash vec,z)\; dz$ where $\backslash vec$ is a vector in the plane of the sky. The deflection angle is then $\backslash vec\; \backslash int\; \backslash frac^)\backslash Sigma(\backslash vec^)\}^|^2\}d^2\; \backslash xi^$ As shown in the diagram on the right, the difference between the unlensed angular position $\backslash vec$ and the observed position $\backslash vec$ is this deflection angle, reduced by a ratio of distances, described as the lens equation $\backslash vec=\backslash vec-\backslash vec(\backslash vec)\; =\; \backslash vec\; -\; \backslash frac\; \backslash vec)$ where $D\_~$ is the distance from the lens to the source $D\_s~$ is the distance from the observer to the source, and $D\_d~$ is the distance from the observer to the lens. For extragalactic lenses, these must be angular diameter distances. In strong gravitational lensing, this equation can have multiple solutions, because a single source at $\backslash vec$ can be lensed into multiple images. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gravitational lensing formalism」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.