Search results for "galaxies : active"

showing 3 items of 3 documents

VLBI detection of the HST-1 feature in the M87 jet at 2 cm

2010

A bright feature 80 pc away from the core in the powerful jet of M87 shows highly unusual properties. Earlier radio, optical and X-ray observations have shown that this feature, labeled HST-1, is superluminal, and is possibly connected with the TeV flare detected by HESS in 2005. It has been claimed that this feature might have a blazar nature, due to these properties. To examine the possible blazar-like nature of HST-1, we analyzed lambda 2 cm VLBA archival data from dedicated full-track observations and the 2 cm survey/MOJAVE VLBI monitoring programs obtained between 2000 and 2009. Applying VLBI wide-field imaging techniques, the HST-1 region was imaged at milliarcsecond resolution. Here …

Active galactic nucleusCosmology and Nongalactic Astrophysics (astro-ph.CO)active [Galaxies]010504 meteorology & atmospheric sciencesRadio galaxyFluxFOS: Physical sciencesgalaxies [Radio continuum]Astrophysics01 natural scienceslaw.inventionlaw0103 physical sciencesVery-long-baseline interferometryUNESCO::ASTRONOMÍA Y ASTROFÍSICA::Otras especialidades astronómicasBlazar010303 astronomy & astrophysicsUNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::Galaxias0105 earth and related environmental sciencesPhysicsSuperluminal motionAstronomy and Astrophysics:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::Galaxias [UNESCO]Radio continuum : galaxies; Techniques : high angular resolution; Techniques : interferometric; Galaxies : active; Galaxies : jetshigh angular resolution [Techniques]InterferometrySpace and Planetary Scienceinterferometric [Techniques]jets [Galaxies]:ASTRONOMÍA Y ASTROFÍSICA::Otras especialidades astronómicas [UNESCO]FlareAstrophysics - Cosmology and Nongalactic Astrophysics
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Radio and gamma-ray properties of extragalactic jets from the TANAMI sample

2016

Using high-resolution radio imaging with VLBI techniques, the TANAMI program has been observing the parsec-scale radio jets of southern (declination south of -30{\deg}) gamma-ray bright AGN simultaneously with Fermi/LAT monitoring of their gamma-ray emission. We present the radio and gamma-ray properties of the TANAMI sources based on one year of contemporaneous TANAMI and Fermi/LAT data. A large fraction (72%) of the TANAMI sample can be associated with bright gamma-ray sources for this time range. Association rates differ for different optical classes with all BL Lacs, 76% of quasars and just 17% of galaxies detected by the LAT. Upper limits were established on the gamma-ray flux from TAN…

AstrofísicaBrightnessCosmology and Nongalactic Astrophysics (astro-ph.CO)010504 meteorology & atmospheric sciencesAstronomyAstrophysics::High Energy Astrophysical PhenomenaFOS: Physical sciencesAstrophysics::Cosmology and Extragalactic AstrophysicsAstrophysics01 natural sciencesDeclinationRadio continuum: galaxies0103 physical sciencesVery-long-baseline interferometryGalaxies; Interferometry; Luminance; Radio astronomy; Temperature Galaxies : active; Galaxies: nuclei; Galaxies:jets; Gamma rays: galaxies; Radio continuum: galaxies Gamma rays; Galaxies: active; Galaxies: jets; Galaxies: nuclei; Gamma rays: galaxies; Radio continuum: galaxiesRadio astronomyBlazar010303 astronomy & astrophysicsAstrophysics::Galaxy AstrophysicsGalaxies: nuclei0105 earth and related environmental sciencesHigh Energy Astrophysical Phenomena (astro-ph.HE)PhysicsGalaxies : activeGalaxies:jetsGamma raysTemperatureGamma rayAstronomy and AstrophysicsQuasarGalaxies: activeGalaxiesGalaxyGamma rays: galaxiesInterferometryLuminanceGalaxies: jetsSpace and Planetary ScienceAstronomiaComputingMethodologies_DOCUMENTANDTEXTPROCESSINGAstrophysics - High Energy Astrophysical PhenomenaAstrophysics - Cosmology and Nongalactic AstrophysicsFermi Gamma-ray Space TelescopeAstronomy & Astrophysics
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The XMM-Newton survey of the ELAIS-S1 field

2006

We have surveyed with XMM-Newton the central ~0.6 deg2 region of the ELAIS-S1 field down to flux limits of ~5.5X10-16 cgs (0.5-2 keV, S band), ~2X10-15 cgs (2-10 keV, H band), and ~4X10-15 cgs (5-10 keV, HH band). We detect a total of 478 sources, 395 and 205 of which detected in the S and H bands respectively. We identified 7 clearly extended sources and estimated their redshift through X-ray spectral fits with thermal models. In four cases the redshift is consistent with z=0.4. We have computed the angular correlation function of the sources in the S and H bands, finding best fit correlation angles theta_0=5.2+/-3.8 arcsec and theta_0=12.8+/-7.8 arcsec respectively. A rough estimate of th…

PhysicsX-rays : galaxieField (physics)galaxies : activeAstrophysics (astro-ph)FOS: Physical sciencesFluxAstronomy and AstrophysicsAstrophysicsH bandAstrophysicsRedshiftDistribution (mathematics)Space and Planetary ScienceRange (statistics)Relative densitylarge-scale structure of UniverseS bandAstronomy & Astrophysics
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