Search results for "BL Lac object"

showing 3 items of 3 documents

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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Multiband variability studies and novel broadband SED modeling of Mrk 501 in 2009

2017

Astronomy and astrophysics 603, A31 (2017). doi:10.1051/0004-6361/201629540

extragalactic background lightmultiwavelength observationsAstrophysics::High Energy Astrophysical Phenomenabl-lacertae objectsGalaxies: BL Lacertae objects: individual: Markarian 501 ; Methods: data analysis ; observational ; Polarizationspectral energy-distributionFluxFOS: Physical sciencesAstrophysics01 natural scienceslaw.inventionindividual: Markarian 501 [BL Lacertae objects]lawCoincident0103 physical sciencesddc:530MAGIC (telescope)crab-nebulaBlazardata analysis [Methods]010303 astronomy & astrophysicsPhysicsHigh Energy Astrophysical Phenomena (astro-ph.HE)tev blazars010308 nuclear & particles physicsstochastic accelerationtelescope observationsInstitut für Physik und AstronomieAstronomy and AstrophysicsAstronomy and Astrophysicgamma-ray emissionmethods: data analysis520BL Lacertae objects: individual: Markarian 501; Methods: data analysisSynchrotrondata analysi [Methods]BL Lacertae objects: individual: Markarian 501; Methods: data analysis; Astronomy and Astrophysics; Space and Planetary ScienceBL Lacertae objects: individual: Markarian 501x-raySpace and Planetary Scienceddc:520ElectrónicaFísica nuclearElectricidadDegeneracy (mathematics)Astrophysics - High Energy Astrophysical PhenomenaFlareBL Lac object
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Changes in the trajectory of the radio jet in 0735+178?

2001

We present multi-epoch 8.4 and 43 GHz Very Long Baseline Array images of the BL Lac object 0735+178. The images confirm the presence of a twisted jet with two sharp apparent bends of 90$^{\circ}$ within two milliarcseconds of the core, resembling a helix in projection. The observed twisted geometry could be the result of precession of the jet inlet, but is more likely produced by pressure gradients in the external medium through which the jet propagates. Quasi-stationary components are observed at the locations of the 90$^{\circ}$ bends, possibly produced by differential Doppler boosting. Identification of components across epochs, since the earliest VLBI observations of this source in 1979…

PhysicsSuperluminal motion010308 nuclear & particles physicsAstrophysics (astro-ph)FOS: Physical sciencesAstronomy and AstrophysicsAstrophysicsViewing angleAstrophysics01 natural sciencessymbols.namesakeLorentz factorSpace and Planetary Science0103 physical sciencesVery-long-baseline interferometrysymbols010303 astronomy & astrophysicsDoppler effectVery Long Baseline ArrayPressure gradientBL Lac object
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