X/Ka-band Component of the proposed ICRF-3: the importance of observation and parameter correlations
Abstract
he candidate ICRF-3 being proposed to the IAU is multi-wavelength consisting of components at S/X(2.3/8.4), K (24 GHz) and X/Ka (8.4/32 GHz). This paper discusses the X/Ka component celestial reference frame which was constructed using a combined NASA and ESA Deep Space Network from 167 observing sessions over which 678 sources were detected covering the full 24 hours of right ascension and the full range of declinations. Observations at X/Ka-band are motivated by their ability to access more compact source morphology and reduced core shift relative to observations at the historically standard S/X-band. In addition, the factor of four increase in interferometer resolution at Ka-band should resolve out some types of astrophysical systematics.
Comparison of 500 X/Ka sources in common with S/X-band (2.3/8.4 GHz) frames yields evidence for systematic errors at the level of hundreds of micro-arcseconds. We discuss the importance of both observation correlations and estimated parameter correlations in evaluating the significance of these systematics differences.- Publication:
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Proceedings of the 10th IVS General Meeting
- Pub Date:
- June 2018
- Bibcode:
- 2018ivs..meetE...3J
- Keywords:
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- ICRF;
- X/Ka-band;
- VLBI;
- astrometry;
- AGN;
- quasar;
- 32 GHz