Search results for "Asars"

showing 4 items of 54 documents

Radio-optical scrutiny of compact AGN

2010

We study the correlations between the VLBA (Very Long Baseline Array) radio emission at 15GHz, extended emission at 151MHz, and optical nuclear emission at 5100{AA} for a complete sample of 135 compact jets. We use the partial Kendall's tau correlation analysis to check the link between radio properties of parsec-scale jets and optical nuclear luminosities of host active galactic nuclei (AGN). Cone search capability for table J/A+A/520/A62/table3 (Optical and radio parameters of 135 AGN)

interstellar mediumgalactic and extragalactic astronomyAstrophysics and Astronomyhigh energy astrophysicsAstrophysics::High Energy Astrophysical PhenomenaPhysicsAstrophysics::Instrumentation and Methods for AstrophysicsAstrophysics::Cosmology and Extragalactic AstrophysicsGalaxiesstellar astronomyOptical astronomyCosmologyobservational astronomyRadio continuum emissionRadio galaxiesRadio astronomyNatural SciencesQuasarsAstrophysics::Galaxy AstrophysicsSpectroscopyVery long baseline interferometry
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The WEBT BL Lacertae Campaign 2001 and its extension : Optical light curves and colour analysis 1994–2002

2004

BL Lacertae has been the target of four observing campaigns by the Whole Earth Blazar Telescope (WEBT) collaboration. In this paper we present UBVRI light curves obtained by theWEBT from 1994 to 2002, including the last, extended BL Lac 2001 campaign. A total of about 7500 optical observations performed by 31 telescopes from Japan to Mexico have been collected, to be added to the ∼15 600 observations of the BL Lac Campaign 2000. All these data allow one to follow the source optical emission behaviour with unprecedented detail. The analysis of the colour indices reveals that the flux variability can be interpreted in terms of two components: longer-term variations occurring on a fewday time …

jetsAstrophysics::High Energy Astrophysical PhenomenaFluxScale (descriptive set theory)activeAstrophysics::Cosmology and Extragalactic AstrophysicsAstrophysicsUNESCO::ASTRONOMÍA Y ASTROFÍSICA01 natural sciencesPower lawlaw.inventionTelescopesymbols.namesakelawBL Lac objects0103 physical sciencesJetsBlazar010303 astronomy & astrophysicsQuasarsAstrophysics::Galaxy AstrophysicsPhysicsactive; galaxies: BL Lacertae objects: general; galaxies: jets; galaxies: quasars: general010308 nuclear & particles physicsActive galaxies ; BL Lacertae objects ; Jets ; Quasarsactive galaxiesAstronomy and AstrophysicsDecoupling (cosmology)galaxies: jetsLight curve:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia [UNESCO]galaxies: quasars: generalSpace and Planetary Scienceactive galaxies; BL Lac objects; jetssymbolsgalaxies: BL Lacertae objects: generalActive galaxiesBL Lacertae objectsUNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogoniaDoppler effect:ASTRONOMÍA Y ASTROFÍSICA [UNESCO]
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Sample of weak blazars at mas resolution

2015

We started a follow-up investigation of the "Deep X-ray Radio Blazar Survey" objects with declination >-10{deg} to better understand the blazar phenomenon. We undertook a survey with the European Very Long Baseline Interferometry Network at 5GHz to make the first images of a complete sample of weak blazars, aiming at a follow-up comparison between high- and low-power samples of blazars. We observed 87 sources with the EVN at 5GHz during the period October 2009 to May 2013. The observations were correlated at the Max-Planck-Institut fuer Radioastronomie and at the Joint Institute for VLBI in Europe. The correlator output was analysed using both the AIPS and DIFMAP software packages. All of t…

observational astronomygalactic and extragalactic astronomyAstrophysics and AstronomyActive galactic nucleihigh energy astrophysicsRadio sourcesPhysicsBL Lacertae objectsRadio astronomyNatural Sciencesstellar astronomyQuasarsCosmology
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Catching the radio flare in CTA 102

2013

Very Long Baseline Interferometry (VLBI) observations can resolve the radio structure of active galactic nuclei (AGN) and provide estimates of the structural and kinematic characteristics on parsec-scales in their jets. The changes in the kinematics of the observed jet features can be used to study the physical conditions in the innermost regions of these sources. We performed multifrequency multiepoch Very Long Baseline Array (VLBA) observations of the blazar CTA102 during its 2006 radio flare, the strongest ever reported for this source. These observations provide an excellent opportunity to investigate the evolution of the physical properties of blazars, especially during these flaring e…

observational astronomygalactic and extragalactic astronomyAstrophysics and Astronomyhigh energy astrophysicsStellar AstronomyPhysicsNatural SciencesQuasarsVery long baseline interferometry
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