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

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https://iopscience.iop.org/article/10.1088/0004-6256/150/2/58
 http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=J/AJ/150/58
 https://ned.ipac.caltech.edu/cgi-bin/objsearch?search_type=Search&refcode=2015AJ....150...58F
 http://simbad.u-strasbg.fr/simbad/sim-ref?querymethod=bib&simbo=on&submit=submit+bibcode&bibcode=2015AJ....150...58F

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http://hdl.handle.net/11603/17528

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UMBC Physics Department
UMBC Center for Space Sciences and Technology (CSST) / Center for Research and Exploration in Space Sciences & Technology II (CRSST II)
UMBC Faculty Collection

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2015-07-24

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journal articles
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Ojha, Roopesh; The Second Realization of the International Celestial Reference Frame by Very Long Baseline Interferometry; The Astronomical Journal, Volume 150, Number 2 (2015); https://iopscience.iop.org/article/10.1088/0004-6256/150/2/58

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This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.

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Abstract

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.