权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Post-Newtonian and Post-post-Newtonian effects in the theory of light propagation for high-precision astrometry

高精度天体测量光传播理论中的后牛顿和后后牛顿效应

基本信息

批准号：
263799048
负责人：
Dr. Sven Zschocke
金额：
--
依托单位：
Professur für Astronomie und Lohrmann-Observatorium
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/263799048?language=en
关键词：
Post Newtonian post effects theory

项目摘要

The ESA astrometry missions Hipparcos (1989-1993) and Gaia (2013-2022) have established a new area in astrometric science, based on wide-field astrometry realized by global astrometric instruments which are designed to measure large angles on the sky. In particular, the Hipparcos final catalogue provides positions, proper motions, and parallaxes of stars up to 1 milli-arcsecond in angular accuracies, while the Gaia mission aims at precisions up to 5 micro-arcseconds in determining positions, proper motions, and parallaxes of stellar objects. The impressive progress made during the realization of these both cornerstone missions of ESA has encouraged the astrometric science to further proceed in nearest future. Among several astrometry missions proposed to ESA we mention the recent M-5 mission proposals Theia, NEAT, and Gaia-NIR, all of which are aiming at the sub-microarcsecond and even nano-arcsecond level of precision. Such unprecedented accuracies necessitate corresponding advancements in the theory of light propagation in the Solar system. Especially, at such level of precision it is necessary to describe the propagation of a light signal in the gravitational field of $N$ arbitrarily moving Solar system bodies having arbitrary shape, inner structure, oscillations and rotational motion. Such a general solution for light trajectories has been determined in the post-Newtonian approximation (1PN and 1.5PN) during the previous period of this DFG project. Also the problem of light propagation in the field of one arbitrarily moving point-like body in the 2PN approximation has been solved. However, there are further aspects of the theory of light propagation which are of decisive importance in order to gain the sub-microarcsecond level of astrometric precision, as there are: (1) treatment of the finite speed of gravitational action (retardation), (2) development of a highly efficient algorithm for real astrometric data reduction, (3) taking into account further 2PN effects of extended bodies, (4) transformation of the light trajectory in the reference system of a space-based observer. These investigations are in line with recent statements of the Senior-Survey-Committee (SSC) of ESA which in response of the selection of science themes for space-based astrometry missions have underlined the importance of proper modeling of light propagation in the Solar system within the general-relativistic framework as fundamental prerequisite for high-precision astrometry in near future. The envisaged project is devoted to these fundamental problems.

欧空局的希巴科斯(-1993年)和盖亚(2013年-2022年)天体测量任务建立了天体测量科学的一个新领域，其基础是通过全球天体测量仪器实现的宽视场天体测量，这些仪器旨在测量天空中的大角度。特别是，伊巴谷最终星表提供了高达1毫角秒的恒星的位置、自行和视差，而盖亚任务的目标是在确定恒星物体的位置、自行和视差方面达到高达5微弧秒的精度。在实现欧空局这两项基石任务期间取得的令人印象深刻的进展鼓励了天体测量科学在不远的将来进一步发展。在向欧空局提出的几项天体测量任务中，我们提到了最近提出的M-5任务计划Theia、Nat和Gaia-NIR，所有这些任务都瞄准了亚微角秒甚至纳角秒级别的精度。如此史无前例的精确度要求太阳系中的光传播理论有相应的进步。特别是，在这样的精度水平下，有必要描述光信号在任意运动的具有任意形状、内部结构、振荡和旋转运动的太阳系物体的引力场中的传播。在DFG项目的前一阶段，已经在后牛顿近似(1Pn和1.5Pn)中确定了这样的光轨迹的一般解。解决了2PN近似下任意运动的类点体场中的光传输问题。然而，光传播理论还有其他方面对于获得亚微弧秒级别的天体测量精度具有决定性的重要性，因为有：(1)处理有限速度的引力作用(迟滞)，(2)开发一种高效的真实天体测量数据简化算法，(3)进一步考虑扩展物体的2PN效应，(4)天基观测者参考系中的光轨迹变换。这些调查与欧空局高级调查委员会最近的声明是一致的，该委员会针对为天基天体测量飞行任务选定的科学主题强调了在一般相对论框架内对太阳系中的光传播进行适当建模作为在不久的将来进行高精度天体测量的基本先决条件的重要性。设想的项目致力于这些根本问题。