Space-borne Optical Interferometer, Astrometric Observing - Data Processing |
Space-borne Optical Interferometer, Astrometric Observing - Data Processing |
Jan 4 2006, 06:05 PM
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#1
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
Paper (*cross-listing*): gr-qc/0007007
Date: Wed, 5 Jul 2000 17:15:54 GMT (7kb) Title: Numerical Data-Processing Simulations of Microarcsecond Classical and Relativistic Effects in Space Astrometry Authors: Sergei M. Kopeikin (University of Missouri-Columbia, USA), N.V. Shuygina, M.V. Vasilyev, E.I. Yagudina (Institute of Applied Astronomy, Russia), L.I. Yagudin (Pulkovo Observatory, Russia) Categories: gr-qc Comments: 5 pages, the talk given at the IAU Coll. 180 "Towards Models and Constants for Sub-Microarcsecond Astrometry", Washington DC, March 26 - April 2, 2000 \\ The accuracy of astrometric observations conducted via a space-borne optical interferometer orbiting the Earth is expected to approach a few microarcseconds. Data processing of such extremely high-precision measurements requires access to a rigorous relativistic model of light ray propagation developed in the framework of General Relativity. The data-processing of the space interferometric observations must rely upon the theory of general-relativistic transformations between the spacecraft, geocentric, and solar barycentric reference systems allowing unique and unambiguous interpretation of the stellar aberration and parallax effects. On the other hand, the algorithm must also include physically adequate treatment of the relativistic effect of light deflection caused by the spherically-symmetric (monopole-dependent) part of the gravitational field of the Sun and planets as well as the quadrupole- and spin-dependent counterparts of it. In some particular cases the gravitomagnetic field induced by the translational motion of the Sun and planets should be also taken into account for unambigious prediction of the light-ray deflection angle. In the present paper we describe the corresponding software program for taking into account all classical (proper motion, parallax, etc.) and relativistic (aberration, deflection of light) effects up to the microarcsecond threshold and demonstrate, using numerical simulations, how observations of stars and/or quasars conducted on board a space optical interferometer orbiting the Earth can be processed and disentangled. \\ ( http://arXiv.org/abs/gr-qc/0007007 , 7kb) -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Jan 4 2006, 06:08 PM
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#2
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
Paper (*cross-listing*): gr-qc/0011031
Date: Wed, 8 Nov 2000 23:35:23 GMT (15kb) Title: Theory of Relativistic Reference Frames for High-Precision Astrometric Space Missions Authors: Sergei M. Kopeikin (University of Missouri-Columbia, USA) Categories: gr-qc Comments: Plenary talk submitted to the Proceedings of the Spanish Relativity Meeting, ERE2000; 12 pages \\ Recent modern space missions deliver invaluable information about origin of our universe, physical processes in the vicinity of black holes and other exotic astrophysical objects, stellar dynamics of our galaxy, etc. On the other hand, space astrometric missions make it possible to determine with unparalleled precision distances to stars and cosmological objects as well as their physical characteristics and positions on the celestial sphere. Permanently growing accuracy of space astronomical observations and the urgent need for adequate data processing algorithms require corresponding development of an adequate theory of reference frames along with unambiguous description of propagation of light rays from a source of light to observer. Such a theory must be based on the Einstein's general relativity and account for numerous relativistic effects both in the solar system and outside of its boundary. The main features of the relativistic theory of reference frames are presented in this work. A hierarchy of the frames is described starting from the perturbed cosmological Friedmann-Robertson-Walker metric and going to the observer's frame through the intermediate barycentric and geocentric frames in the solar system. Microarcsecond astrometry and effects of propagation of light rays in time-dependent gravitational fields are discussed as well. \\ ( http://arXiv.org/abs/gr-qc/0011031 , 15kb) -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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Mar 15 2006, 04:46 PM
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#3
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Senior Member Group: Members Posts: 2454 Joined: 8-July 05 From: NGC 5907 Member No.: 430 |
Astrophysics, abstract
astro-ph/0603265 From: Pankaj Jain [view email] Date: Fri, 10 Mar 2006 11:59:00 GMT (181kb) Interferometric Parallax: A Method for Measurement of Astronomical Distances Authors: Pankaj Jain, John P. Ralston Comments: 4 pages, 1 figure We show that distances of objects at cosmological distances can be measured directly using interferometry. Our approach to interferometric parallax comes from analysis of 4-point amplitude and intensity correlations that can be generated from pairs of well-separated detectors. The baseline required to measure cosmological distances of Gigaparsec order are within the reach of the next generation of space-borne detectors. The semi-classical interpretation of intensity correlations uses a notion of a single photon taking two paths simultaneously. Semi-classically a single photon can simultaneously enter four detectors separated by an astronomical unit, developing correlations feasible to measure with current technology. http://arxiv.org/abs/astro-ph/0603265 -------------------- "After having some business dealings with men, I am occasionally chagrined,
and feel as if I had done some wrong, and it is hard to forget the ugly circumstance. I see that such intercourse long continued would make one thoroughly prosaic, hard, and coarse. But the longest intercourse with Nature, though in her rudest moods, does not thus harden and make coarse. A hard, sensible man whom we liken to a rock is indeed much harder than a rock. From hard, coarse, insensible men with whom I have no sympathy, I go to commune with the rocks, whose hearts are comparatively soft." - Henry David Thoreau, November 15, 1853 |
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