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Optical spectra of southern flat-spectrum IVS radio sources

Created 16/10/2025

Updated 16/10/2025

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About 1200 radio quasars are observed regularly by the International VLBI Service, IVS, to define and maintain the International Celestial Reference Frame, ICRF. We have presented evidence for large scale systematic proper motions, dipole and quadrupole effects, at a level in excess of 10 µas/year. This result presents a serious challenge to the standard cosmologies. However, we have a concern that our estimates of the spherical harmonics may be influenced by the paucity of IVS quasars with known redshifts in the south. We estimate that 100--150 new redshifts uniformly distributed in the south will remove these concerns. In this paper the results of spectroscopic observations of 43 southern radio sources with 3.58-meter NTT telescope are presented. Paper presented at the 20th Meeting of the European VLBI Group for Geodesy and Astronomy

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Additional Info

Field Value
Title Optical spectra of southern flat-spectrum IVS radio sources
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/f2f4166b-6b4f-44f2-bdb8-14459c686aaa
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        112.92,
        -54.75
      ],
      [
        159.11,
        -54.75
      ],
      [
        159.11,
        -9.2402
      ],
      [
        112.92,
        -9.2402
      ],
      [
        112.92,
        -54.75
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Optical spectra of southern flat-spectrum IVS radio sources". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/optical-spectra-of-southern-flat-spectrum-ivs-radio-sources