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Scintillation is an indicator of astrometric stability

Citation

Schaap, RG and Shabala, SS and Ellingsen, SP and Titov, OA and Lovell, JEJ, Scintillation is an indicator of astrometric stability, Monthly Notices of the Royal Astronomical Society, 434, (1) pp. 585-594. ISSN 0035-8711 (2013) [Refereed Article]

Copyright Statement

Copyright 2013 The Authors

DOI: doi:10.1093/mnras/stt1049

Abstract

We examine the relationship between astrometric stability and astrophysical properties in flat-spectrum radio-loud quasars making up the celestial reference frame. We use position determinations from geodetic very long baseline interferometry measurements and develop a new metric for source position stability. We then compare this quantity to two measures of source compactness: structure index, which probes structure on milliarcsecond scales and the presence of interstellar scintillation associated with the quasar, which probes scales of tens of μas.

We find that persistent scintillators have greater position stability than episodic scintillators, which are in turn more stable than non-scintillators. Scintillators are also more likely to be compact on milliarcsecond scales, as measured by the structure index. Persistent scintillators are therefore excellent candidates for inclusion in any future realization of the celestial reference frame. A list of these sources is presented in Appendix A.

We find that slow (characteristic time-scale >3 d) scintillators have more stable positions than rapid scintillators, suggesting that they are more compact. High-cadence, long-term monitoring is therefore required to identify other members of this population of compact, high brightness temperature quasars.

Item Details

Item Type:Refereed Article
Keywords:scattering – astrometry – reference systems – ISM: structure – quasars: general
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:Cosmology and Extragalactic Astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
Author:Schaap, RG (Mr Robert Schaap)
Author:Shabala, SS (Dr Stas Shabala)
Author:Ellingsen, SP (Professor Simon Ellingsen)
Author:Lovell, JEJ (Dr Jim Lovell)
ID Code:86235
Year Published:2013
Web of Science® Times Cited:4
Deposited By:Mathematics and Physics
Deposited On:2013-08-30
Last Modified:2017-11-01
Downloads:0

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