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VLBI measurement of the secular aberration drift

Created 17/10/2025

Updated 17/10/2025

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Aims. While analyzing decades of very long baseline interferometry (VLBI) data, we detected the secular aberration drift of the extragalatic radio source proper motions caused by the rotation of the Solar System barycenter around the Galactic center. Our results agree with the predicted estimate to be 4–6 micro arcseconds per year (μas/yr) towards α = 266° and δ = −29°. In addition, we tried to detect the quadrupole systematics of the velocity field. Methods. The analysis method consisted of three steps. First, we analyzed geodetic and astrometric VLBI data to produce radio source coordinate time series. Second, we fitted proper motions of 555 sources with long observational histories over the period 1990–2010 to their respective coordinate time series. Finally, we fitted vector spherical harmonic components of degrees 1 and 2 to the proper motion field. Results. Within the error bars, the magnitude and the direction of the dipole component agree with predictions. The dipole vector has an amplitude of 6.4 ± 1.5 μas/yr and is directed towards equatorial coordinates α = 263° and δ = −20°. The quadrupole component has not been detected. The primordial gravitational wave density, integrated over a range of frequencies less than 10-9 Hz, has a limit of 0.0042h-2 where h is the normalized Hubble constant is H0/(100 km s-1). Citation: Titov, O., Lambert, S. B., & Gontier, A.-M. (2011). VLBI measurement of the secular aberration drift. Astronomy & Astrophysics, 529, A91. https://doi.org/10.1051/0004-6361/201015718

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Field Value
Title VLBI measurement of the secular aberration drift
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/539dcbcf-af7d-4d2c-96f9-c4cfbb36a264
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period
Geospatial Coverage
Map data © OpenStreetMap contributors
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        -44.0
      ],
      [
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        -44.0
      ],
      [
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      ],
      [
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        -9.0
      ],
      [
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      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "VLBI measurement of the secular aberration drift". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/vlbi-measurement-of-the-secular-aberration-drift