Authors / CoAuthors
Titov, O.
Abstract
The individual apparant motion of distant radio sources is supposed to be caused by the effect of intrinsic structure variations of the active galactic nuclei (AGN) and not correlated over the sky. However, some models of the expanded Universe predict that systematic astrometric proper motion of distant radio sources do not vanish as radial distance from observer to the source grows. These systematic effects can even increase with the distance making possible to measure them with high-precision astrometric techniques like VLBI. The Galactocentric acceleration of the Solar system barycentre might cause a secular aberration drift with magnitude 4 microarcsec/year. Also the Solar system motion relative to the cosmic microwave background produces additional dipole effect, dependent on red shift. We analyzed a large set of geodetic VLBI data spanning from 1979 till 2008 to estimate the dipole, the rotational, and the quadrupole harmonics in the expansion of the vector field of the proper motions of quasars in the sky. The dipole and quadrupole vector spherical harmonics from the individual apparent motion of 687 radio sources were estimated. In addition, the estimates have been obtained separately for different red shift zones. We show that for the next decade the geodetic VLBI technique might approach to the level of accuracy to test the cosmological models of the Universe. It is important to organise a dedicated observational program to increase the number of measured proper motion to ~3000.
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nonGeographicDataset
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70342
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- External Publication
- ( Theme )
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- geodesy
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
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2010-01-01T00:00:00
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