The ICRF-3: A Proposed Roadmap to the Next Generation International Celestial Reference Frame

Robert Heinkelmann Christopher S. Jacobs F. Arias D. Boboltz J. Boehm S. Bolotin G. Bourda 1 P. Charlot 1 A. De Witt A. Fey R. Gaume 2 D. Gordon 3 S. Lambert 4 C. Ma Z. Malkin 5 A. Nothnagel M. Seitz E. Skuikhina J. Souchay 6 O. Titov
1 M2A 2013
L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux, OASU - Observatoire aquitain des sciences de l'univers, LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac], Université Sciences et Technologies - Bordeaux 1
Abstract : The International Celestial Reference Frame's current realization, the ICRF-2 (Ma et al, 2009), has the potential to be improved in several ways. In order to achieve this potential in time for comparisons with ESA's optical Gaia mission, the IAU has formed the ICRF-3 working group with the goal of producing the next generation ICRF by its 2018 General Assembly. With Gaia aiming for sub-100 μas precision for quasars in its frame, our goal for the ICRF-3 is to achieve sub-100 μas precision in the radio for as many sources at as many observing bands as possible. This talk will review the intiatives underway which collectively form our roadmap for achieving these goals. VCS-II: Noting that ~2/3 of the ICRF-2's 3414 sources have been observed in only 1 or 2 sessions (mostly the VLBA Calibrator Survey (VCS)) which produced median precisions of 620/ 1120 μas in RAcosDec/ Dec, respectively, we have instigated a collaboration to re-observe the VCS sources using modern systems which are 5 times more sensitive than the original VCS system. This will allow the VCS sources to have precision more nearly comparable to the other ICRF sources. High Frequency radio: Noting that comparison of radio frame to the Gaia optical frame will require an accurate undersanding of frequency dependent changes in source morphology (source structure) and frequency dependent opacity effects (core shift), we are encouraging the construction of 100 μas precision radio frames at multple radio frequencies such as X/Ka (8.4/32 Ghz), K-band (~24 GHz) and Q-band (43 GHz). Southern coverage: Noting that all current radio frames have poorer spatial covereage and precision in the southern hemisphere, we are encouraging increased astrometric observations from the southern hemisphere. Observations using stations from Australia, South Africa, and Argentina are currently being organized. Frame consistency: Noting that Celestial Reference Frames are often used in combination with other frames such as the planetary emphemeris, the Earth Orientation Parameters (EOP), and the International Terrestrial Reference Frame (ITRF) which are of keen interest to geodesists and planetary scientists, a key ICRF-3 goal is to maintain and improve consistency with these other frames. This component of the work will study various combination techniques such as multi-technique data combinations for EOPs and TRFs, combined radio frames, and various modelling improvements such as galactic abberration.
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https://hal.archives-ouvertes.fr/hal-00944268
Contributeur : Marie-Paule Pomies <>
Soumis le : lundi 10 février 2014 - 14:20:59
Dernière modification le : mardi 10 octobre 2017 - 13:46:22

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Robert Heinkelmann, Christopher S. Jacobs, F. Arias, D. Boboltz, J. Boehm, et al.. The ICRF-3: A Proposed Roadmap to the Next Generation International Celestial Reference Frame. -, 2013, Potsdam, Germany. pp.1, 2013. 〈hal-00944268〉

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