Search results for "Radio continuum: general"

showing 2 items of 2 documents

Absolute kinematics of radio-source components in the complete S5 polar cap sample: IV. Proper motions of the radio cores over a decade and spectral …

2016

We have carried out a high-precision astrometric analysis of two very-long-baseline-interferometry (VLBI) epochs of observation of the 13 extragalactic radio sources in the complete S5 polar cap sample. The VLBI epochs span a time baseline of ten years and enable us to achieve precisions in the proper motions of the source cores up to a few micro-arcseconds per year. The observations were performed at 14.4 GHz and 43.1 GHz, and enable us to estimate the frequency core-shifts in a subset of sources, for which the spectral-index distributions can be computed. We study the source-position stability by analysing the changes in the relative positions of fiducial source points (the jet cores) ove…

AstrofísicaActive galactic nucleusAstrometriaAstrophysics::High Energy Astrophysical PhenomenaFOS: Physical sciencesAstrophysics::Cosmology and Extragalactic AstrophysicsAstrophysicsKinematics01 natural sciencesStability (probability)Radio continuum: generalBinary black hole0103 physical sciencesVery-long-baseline interferometry010306 general physicsInstrumentation and Methods for Astrophysics (astro-ph.IM)010303 astronomy & astrophysicsAstrophysics::Galaxy AstrophysicsPhysicsJet (fluid)general [Radio continuum]general [BL Lacertae objects]Astrophysics::Instrumentation and Methods for AstrophysicsAstronomy and Astrophysicsgeneral [Quasars]BL Lacertae objects: generalAstrometryAstrometryAstrophysics - Astrophysics of GalaxiesQuasars: generalGravitational lensSpace and Planetary ScienceAstrophysics of Galaxies (astro-ph.GA)Techniques: interferometricinterferometric [Techniques]Astrophysics - Instrumentation and Methods for Astrophysics
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Young, active radio stars in the AB Doradus moving group

2017

Context. Precise determination of stellar masses is necessary to test the validity of pre-main-sequence (PMS) stellar evolutionary models, whose predictions are in disagreement with measurements for masses below 1.2 M. To improve such a test, and based on our previous studies, we selected the AB Doradus moving group (AB Dor-MG) as the best-suited association on which to apply radio-based high-precision astrometric techniques to study binary systems. Aims. We seek to determine precise estimates of the masses of a set of stars belonging to the AB Dor-MG using radio and infrared observations. Methods. We observed in phase-reference mode with the Very Large Array (VLA) at 5 GHz and with the Eur…

European VLBI NetworkInfraredFOS: Physical sciencesContext (language use)Astrophysics01 natural sciencesRadio continuum: generalObservatorypre-main sequence [Stars]0103 physical sciencesBinaries: general010303 astronomy & astrophysicsSolar and Stellar Astrophysics (astro-ph.SR)PhysicsOrbital elementsgeneral [Binaries]010308 nuclear & particles physicsgeneral [Radio continuum]Astronomy and AstrophysicsAstrometryCoronaStarsAstrophysics - Solar and Stellar AstrophysicsSpace and Planetary ScienceStars: pre-main sequenceAB Doradus moving group
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