Results 31 to 40 of about 39,820 (206)
Intraday radio variability in active galactic nuclei
New Astronomy Reviews, 1999 Rapid flux density variations on timescales of the order of a day or less (Intraday Variability, IDV) in the radio regime are a common phenomenon within the blazar class. Observations with the 100m telescope of the MPIfR showed that the variations occur not only in total intensity, but also in the polarized intensity and in polarization angle.
Kraus, A., Witzel, A., Krichbaum, T. P.
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NGC 5252: a pair of radio-emitting active galactic nuclei? [PDF]
Monthly Notices of the Royal Astronomical Society: Letters, 2016 Abstract The X-ray source CXO J133815.6+043255 has counterparts in the UV, optical, and radio bands. Based on the multiband investigations, it has been recently proposed by Kim et al. as a rarely seen off-nucleus ultraluminous X-ray (ULX) source with a black hole mass of ≥104 M⊙ in the nearby Seyfert galaxy NGC 5252. To explore its radio
Yang, Xiaolong +9 more
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Radio Emission from Active Galactic Nuclei [PDF]
Symposium - International Astronomical Union, 1987 Active Galactic Nuclei and quasars are characterized at radio wavelengths by a high surface brightness, a flat spectrum, variations in intensity on time scales of a few days to a few years, and by large internal motions which probably reflect Doppler beaming from a synchrotron source which is moving with relativistic velocity away from the central ...
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Radio Emission from Low-Luminosity Active Galactic Nuclei [PDF]
International Astronomical Union Colloquium, 1998 AbstractMany nearby galaxies show optical evidence for low-luminosity AGNs that are far less luminous than classical Seyfert nuclei and QSOs. LINERs, the most common variety of such emission-line objects, comprise ~ 1/3 of nearby galaxies, and may serve as an important “missing link“ between normal and Seyfert galaxies.
Schuyler D. Van Dyk, Luis C. Ho
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Optical-radio positional offsets for active galactic nuclei [PDF]
Astronomy & Astrophysics, 2013 Context. It will soon become possible to directly link the most accurate radio reference frame with the Gaia optical reference frame using many common extragalactic objects. It is important to know the level of coincidence between the radio and optical positions of compact active galactic nuclei (AGN). Aims.
Orosz, Gábor, Frey, Sándor
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Hot Dust in Radio-loud Active Galactic Nuclei
The Astrophysical Journal, 2003 12 pages, 2 figures. To appear in ApJ Letters. Also available at http://stecf.org/~wfreudli/pubs/
Wolfram Freudling +2 more
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Jet reorientation in active galactic nuclei: two winged radio galaxies [PDF]
Monthly Notices of the Royal Astronomical Society, 2002 Winged, or X-shaped, radio sources form a small class of morphologically peculiar extragalactic sources. We present multifrequency radio observations of two such sources. We derive maximum ages since any re-injection of fresh particles of 34 and 17 Myr for the wings of 3C 223.1 and 3C 403 respectively, based on the lack of synchrotron and inverse ...
Dennett-Thorpe, J. +5 more
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Do radio active galactic nuclei reflect X-ray binary spectral states? [PDF]
Astronomy & Astrophysics, 2022 Context.Over recent years there has been mounting evidence that accreting supermassive black holes in active galactic nuclei (AGNs) and stellar mass black holes have similar observational signatures: thermal emission from the accretion disk, X-ray coronas, and relativistic jets.
Emily Moravec +7 more
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Millimeter-Wave Monitoring of Active Galactic Nuclei with the Africa Millimetre Telescope
Galaxies, 2019 Active galactic nuclei are the dominant sources of gamma rays outside our galaxy and are also candidates for the source of ultra-high energy cosmic rays.
Michael Backes +2 more
doaj +1 more source
Detecting the 21 cm Forest in the 21 cm Power Spectrum
, 2014 We describe a new technique for constraining the radio loud population of active galactic nuclei at high redshift by measuring the imprint of 21 cm spectral absorption features (the 21 cm forest) on the 21 cm power spectrum.
Dillon, Joshua S. +3 more
core +1 more source