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The Second Realization of the International Celestial Reference Frame by Very Long Baseline Interferometry

Created 16/10/2025

Updated 16/10/2025

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We present the second realization of the International Celestial Reference Frame (ICRF2) at radio wavelengths using nearly 30 years of Very Long Baseline Interferometry observations. ICRF2 contains precise positions of 3414 compact radio astronomical objects and has a positional noise floor of ∼40 μas and a directional stability of the frame axes of ∼10 μas. A set of 295 new “defining” sources was selected on the basis of positional stability and the lack of extensive intrinsic source structure. The positional stability of these 295 defining sources and their more uniform sky distribution eliminates the two greatest weaknesses of the first realization of the International Celestial Reference Frame (ICRF1). Alignment of ICRF2 with the International Celestial Reference System was made using 138 positionally stable sources common to both ICRF2 and ICRF1. The resulting ICRF2 was adopted by the International Astronomical Union as the new fundamental celestial reference frame, replacing ICRF1 as of 2010 January 1. Citation: Fey, A. L., Gordon, D., Jacobs, C. S., Ma, C., Gaume, R. A., Arias, E. F., Bianco, G., Boboltz, D. A., Böckmann, S., Bolotin, S., Charlot, P., Collioud, A., Engelhardt, G., Gipson, J., Gontier, A.-M., Heinkelmann, R., Kurdubov, S., Lambert, S., Lytvyn, S., ... Zharov, V. (2015). The second realization of the International Celestial Reference Frame by Very Long Baseline Interferometry. The Astronomical Journal, 150(2), 58. https://doi.org/10.1088/0004-6256/150/2/58

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Title The Second Realization of the International Celestial Reference Frame by Very Long Baseline Interferometry
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/90638f7a-81e4-4624-9cb6-c15fbd7a2432
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
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Geospatial Coverage Australia
Data Portal Geoscience Australia

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This dataset was originally found on Geoscience Australia "The Second Realization of the International Celestial Reference Frame by Very Long Baseline Interferometry". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/the-second-realization-of-the-international-celestial-reference-frame-by-very-long-baseline-int