VLBI measurement of the secular aberration drift

Titov, Oleg; Lambert, S.; Gontier, A. M.

doi:10.1051/0004-6361/201015718

Cited by 104 publications

(167 citation statements)

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“…This is to be compared with the VLBI estimate Ω GW < 0.11 h −2 for ν < 2 × 10 −9 Hz of Gwinn et al (1997). The same approach applied to the VLBI catalogue used by Titov et al (2011) gives Ω GW < 0.009 h −2 for ν < 1.5 × 10 −9 Hz. Therefore, one can expect that Gaia will improve current estimates from VLBI data by two orders of magnitude while covering a larger interval of frequencies.…”

Section: Main Results Of the Analysis Of The Simulated Qso Cataloguementioning

confidence: 98%

“…to the QSOs, while the spheroidal coefficients of order 1 give the acceleration of the solar system with respect to the QSOs, which shows up as a glide (Fanselow 1983;Sovers et al 1998;Kovalevsky 2003;Kopeikin & Makarov 2006;Titov et al 2011). The VSH coefficients of order 2 can be related to the energy flux of the ultra-low-frequency gravity waves (Gwinn et al 1997).…”

Section: Analysis Of the Expected Gaia Resultsmentioning

confidence: 99%

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Analysis of astrometric catalogues with vector spherical harmonics

Mignard

2012

A&A

123

156

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Aims. We compare stellar catalogues with position and proper motion components using a decomposition on a set of orthogonal vector spherical harmonics. We aim to show the theoretical and practical advantages of this technique as a result of invariance properties and the independence of the decomposition from a prior model. Methods. We describe the mathematical principles used to perform the spectral decomposition, evaluate the level of significance of the multipolar components, and examine the transformation properties under space rotation. Results. The principles are illustrated with a characterisation of systematic effects in the FK5 catalogue compared to Hipparcos and with an application to extraction of the rotation and dipole acceleration in the astrometric solution of QSOs expected from Gaia.

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Section: Main Results Of the Analysis Of The Simulated Qso Cataloguementioning

confidence: 98%

Section: Analysis Of the Expected Gaia Resultsmentioning

confidence: 99%

Analysis of astrometric catalogues with vector spherical harmonics

Mignard

2012

A&A

123

156

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“…Therefore in this paper we only consider the main galactocentric component of the acceleration and we call the corresponding aberration effect "Galactic aberration" after Malkin (2011). This effect has also been called "secular aberration" (Kopeikin & Makarov 2006), "secular aberration drift" (Titov 2010;Titov et al 2011), or "aberration in proper motions" (Kovalevsky 2003), but no official nomenclature has been adopted so far 1 . Titov (2010Titov ( , 2011 calls attention to the need to take the Galactic aberration effect into account in high-precision astrometric data reductions in the future development of the ICRF and in geodetic/astrometric VLBI software packages.…”

Section: Introductionmentioning

confidence: 99%

“…Titov (2010Titov ( , 2011 calls attention to the need to take the Galactic aberration effect into account in high-precision astrometric data reductions in the future development of the ICRF and in geodetic/astrometric VLBI software packages. To detect the Galactic aberration effect, Titov et al (2011) analyzed VLBI data over the period 1990−2010 to produce the coordinate time series of 555 radio sources. With the linear proper motions fitted to these series, they obtained the amplitude and apex of the dipole structure, which are consistent, within the error bars, with the theoretical predictions.…”

Section: Introductionmentioning

confidence: 99%

Systematic effect of the Galactic aberration on the ICRS realization and the Earth orientation parameters

Liu¹,

Capitaine²,

Lambert³

et al. 2012

A&A

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Context. The curvature of the motion of the solar system barycenter around the Galactic center induces an aberration effect varying linearly with time. It can be called the "Galactic aberration" and is also known as the "secular aberration (drift)" or "aberration in proper motions". This results in a systematic dipole pattern of the apparent proper motions of an ensemble of distant extragalactic objects, which are used to define the International Celestial Reference System (ICRS). Aims. The purpose of this paper is to investigate the effect of the Galactic aberration on the ICRS realization and on the Earth orientation parameters (EOP), which refer to the ICRS. Methods. We first computed the global rotation of the celestial reference system resulting from the Galactic aberration effect on the apparent proper motions of the ensemble of extragalactic objects that realize this system. Then we evaluated the influence of the Galactic aberration on the EOP using CIO based ICRS-to-ITRS coordinate transformation. Numerical evaluations of the effect were performed with the ICRF1 and ICRF2 catalogs over short and long time intervals. Results. We show that the effect of the Galactic aberration strongly depends on the distribution of the sources that are used to realize the ICRS. According to different distributions of sources (of the ICRF1 and ICRF2 catalogs) the amplitude of the apparent rotation of the ICRS is included between about 0.2 and 1 microarcsecond per year (μas yr −1 ). We show that this rotation has no component around the axis pointing to the Galactic center and has an zero amplitude in the case of uniform distribution of sources. The effect on the coordinates of the Celestial intermediate pole (CIP) is included between about 1 to 100 μas after one century from J2000.0, while the effects on the Earth rotation angle (ERA) are from 4 to several tens of μas after one century. Conclusions. We demonstrate that the Galactic aberration is responsible for a variation with time of the orientation of the ICRS axes and consequently for systematic errors on the determination of the EOP, which refer to the ICRS. The effect on the ICRS and EOP increases with time and is not negligible after several tens of years. With high-accuracy astrometry and the increasing length of the available VLBI observation time series, this effect should be considered, particularly in constructing the next realization of the ICRS. Observations of more radio sources, especially in the southern hemisphere should be developed to more homogeneously distribute defining sources in the ICRF to minimize that effect.

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“…On might introduce some galacto-centric celestial reference system; but since the problem of galactic rotation will not be touched (e.g. Lambert 2011, Titov et al 2011 this also will not be needed. One might modify the BCRS to account for the Hubble expansion of the universe; an attempt in this direction can be found e.g.…”

Section: An Advanced Relativistic Vlbi Model For Geodesymentioning

confidence: 99%

Advanced relativistic VLBI model for geodesy

Söffel

Kopeikin

Han

2016

J Geod

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Abstract:Our present relativistic part of the geodetic VLBI model for Earthbound antennas is a consensus model which is considered as a standard for processing high-precision VLBI observations. It was created as a compromise between a variety of relativistic VLBI models proposed by different authors as documented in the IERS Conventions 2010. The accuracy of the consensus model is in the picosecond range for the group delay but this is not sufficient for current geodetic pur-poses. This paper provides a fully documented derivation of a new relativistic model having an accuracy substantially higher than one picosecond and based upon a well accepted formalism of relativistic celestial mechanics, astrometry and geodesy. Our new model fully confirms the consensus model at the picosecond level and in several respects goes to a great extent beyond it. More specifically, terms related to the acceleration of the geocenter are considered and kept in the model, the gravitational time-delay due to a massive body (planet, Sun, etc.) with arbitrary mass and spin-multipole moments is derived taking into account the motion of the body, and a new formalism for the time-delay problem of radio sources located at finite distance from VLBI stations is presented. Thus, the paper presents a substantially elaborated theoretical justification of the consensus model and its significant extension that allows researchers to make concrete estimates of the magnitude of residual terms of this model for any conceivable configuration of the source of light, massive bodies, and VLBI stations. The largest terms in the relativistic time delay which can affect the current VLBI observations are from the quadrupole and the angular momentum of the gravitating bodies that are known from the literature. These terms should be included in the new geodetic VLBI model for improving its consistency.

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VLBI measurement of the secular aberration drift

Cited by 104 publications

References 30 publications

Analysis of astrometric catalogues with vector spherical harmonics

Analysis of astrometric catalogues with vector spherical harmonics

Systematic effect of the Galactic aberration on the ICRS realization and the Earth orientation parameters

Advanced relativistic VLBI model for geodesy

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