Extending the ICRF to Higher Radio Frequencies: Global Astrometric Results at 24 GHz

C. S. Jacobs (1) , G. E. Lanyi (1) , C. J. Naudet (1) , O. J. Sovers (1) , L. D. Zhang (1) , P. Charlot (2, 3, 4) , E. B. Fomalont (5) , D. Gordon (6) , C. Ma (6) , Kq Vlbi Collaboration

1 JPL - Jet Propulsion Laboratory
2 L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux
3 OASU - Observatoire aquitain des sciences de l'univers
4 LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac]
5 NRAO - National Radio Astronomy Observatory
6 GSFC - NASA Goddard Space Flight Center

A celestial reference frame at K-band (24 GHz) has been constructed using eight 24-hour VLBA sessions which covered the full 24 hours of right ascension and declinations down to -40 deg. The resulting catalog contains 259 sources with median formal position uncertainties of 100 micro-arcsec in RA cos(dec) and 200 microarcsec in declination. In order to constrain the long arcs of the K-band catalog to those obtained with the S/X-band ICRF, four K-band high quality source positions well-separated in the sky were set to the S/X-band positions. After this registration, comparison of the K-band frame to an S/X-band ICRF-like frame shows agreement of 200 micro-arcsec in RA cos(dec) and 300 micro-arcsec in declination. The motivations for extending the ICRF to frequencies above 8 GHz are to use more compact sources less susceptible to structure changes in order to construct a more stable frame, to provide calibrators for phase referencing, and to support spacecraft navigation at higher frequencies.

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Astrophysique [astro-ph]

C. S. Jacobs, G. E. Lanyi, C. J. Naudet, O. J. Sovers, L. D. Zhang, et al.. Extending the ICRF to Higher Radio Frequencies: Global Astrometric Results at 24 GHz. International VLBI Service for Geodesy and Astrometry 2006 General Meeting Concepcion (Chile), January 9-11, 2006,, 2006, Concepción, Chile. pp.320. ⟨hal-00109338⟩