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VLBI observations of optically-bright extragalactic radio sources for the alignment of the radio frame with the future Gaia frame. I. Source detection
- Source :
- Astronomy and Astrophysics-A&A, Astronomy and Astrophysics-A&A, EDP Sciences, 2010, 520, pp.113. ⟨10.1051/0004-6361/201014248⟩
- Publication Year :
- 2010
- Publisher :
- HAL CCSD, 2010.
-
Abstract
- International audience; Context. The European space astrometry mission Gaia will construct a dense optical QSO-based celestial reference frame. For consistency between optical and radio positions, it will be important to align the Gaia and VLBI frames with the highest possible accuracy. It has been found that only 70 (10%) of the sources from the International Celestial Reference Frame (ICRF) are suitable for establishing this link, either because they are not bright enough at optical wavelengths or because they have significant extended radio emission which precludes reaching the highest astrometric accuracy. Aims: In order to improve the situation, we have initiated a VLBI survey dedicated to finding additional suitable radio sources for aligning the two frames. Methods: The sample consists of 447 optically-bright (magnitude ≤18) extragalactic radio sources, typically 20 times weaker than the ICRF sources, which have been selected by cross-correlating an optical quasar catalog with the NRAO VLA Sky Survey (NVSS). Results: This paper presents the observing strategy to detect, image, and measure accurate radio positions for these sources. It also provides results on the VLBI detectability of the sources, as derived from initial observations with the European VLBI Network in June and October 2007. Based on these observations, a high detection rate of 89% is found, which is promising for the continuation of this project. This high VLBI detection rate for sources from the NVSS catalog is probably due to the selection process, suggesting that optically-bright quasars have compact radio structures. The entire list of radio sources detected (i.e. complete Table 3) is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/520/A113
- Subjects :
- European VLBI Network
010504 meteorology & atmospheric sciences
Astrophysics::High Energy Astrophysical Phenomena
Context (language use)
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
01 natural sciences
quasars: general
0103 physical sciences
Very-long-baseline interferometry
reference systems
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
0105 earth and related environmental sciences
NRAO VLA Sky Survey
Physics
Astrophysics::Instrumentation and Methods for Astrophysics
Astronomy
Astronomy and Astrophysics
Quasar
Astrometry
[PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA]
13. Climate action
Space and Planetary Science
techniques: interferometric
International Celestial Reference Frame
astrometry
[SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA]
methods: observational
catalogs
Reference frame
Subjects
Details
- Language :
- English
- ISSN :
- 00046361
- Database :
- OpenAIRE
- Journal :
- Astronomy and Astrophysics-A&A, Astronomy and Astrophysics-A&A, EDP Sciences, 2010, 520, pp.113. ⟨10.1051/0004-6361/201014248⟩
- Accession number :
- edsair.doi.dedup.....6d133f7f78208d385ac05d05783c4d08
- Full Text :
- https://doi.org/10.1051/0004-6361/201014248⟩