0000000000433185

AUTHOR

K. J. Johnston

showing 3 related works from this author

The Evolution of Outbursts in Cygnus X-3 at 2.25 and 8.3 GHz

1995

PhysicsSpace and Planetary ScienceAstronomyAstronomy and AstrophysicsAstrophysicsThe Astronomical Journal
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Astrometric detection of a low-mass companion orbiting the star AB Doradus

1997

International audience; We report submilliarcsecond-precise astrometric measurements for the late-type star AB Doradus via a combination of VLBI (very long baseline interferometry) and HIPPARCOS data. Our astrometric analysis results in the precise determination of the kinematics of this star, which reveals an orbital motion readily explained as caused by gravitational interaction with a low-mass companion. From the portion of the reÑex orbit covered by our data and using a revised mass of the primary star (0.76 M _) derived from our new value of the parallax (66.3 mas \ n \ 67.2 mas), we Ðnd the dynamical mass of the newly discovered companion to be between 0.08 and 0.11 If accurate photom…

010504 meteorology & atmospheric sciencesGalactic astronomyStellar massBrown dwarfAstrophysicsAstrophysics::Cosmology and Extragalactic Astrophysics01 natural sciencesstars: low-mass0103 physical sciencesVery-long-baseline interferometryAstrophysics::Solar and Stellar Astrophysics010303 astronomy & astrophysicsAstrophysics::Galaxy Astrophysics0105 earth and related environmental sciencesPhysicsstars: individual (AB Doradus)[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR]Astrophysics::Instrumentation and Methods for AstrophysicsAstronomyAstronomy and AstrophysicsAstrometryInterferometrySpace and Planetary Sciencetechniques: interferometricOrbital motionastrometryAstrophysics::Earth and Planetary Astrophysics[SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA]stars: kinematicsLow Massbrown dwarfs
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TANAMI: tracking active galactic nuclei with austral milliarcsecond interferometry

2010

We introduce the TANAMI program (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry) which is monitoring an initial sample of 43 extragalactic jets located south of -30 degrees declination at 8.4 GHz and 22 GHz since 2007. All aspects of the program are discussed. First epoch results at 8.4 GHz are presented along with physical parameters derived therefrom. We present first epoch images for 43 sources, some observed for the first time at milliarcsecond resolution. Parameters of these images as well as physical parameters derived from them are also presented and discussed. These and subsequent images from the TANAMI survey are available at http://pulsar.sternwarte.uni…

High Energy Astrophysical Phenomena (astro-ph.HE)PhysicsBrightnessCosmology and Nongalactic Astrophysics (astro-ph.CO)Active galactic nucleusEpoch (astronomy)FOS: Physical sciencesAstronomy and AstrophysicsQuasarAstrophysicsDeclinationGalaxyRedshiftInterferometrySpace and Planetary ScienceAstrophysics - High Energy Astrophysical PhenomenaAstrophysics - Cosmology and Nongalactic AstrophysicsAstronomy and Astrophysics
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