Results 21 to 30 of about 40,224 (203)
The radio dichotomy of active galactic nuclei [PDF]
Publications of the Astronomical Society of Japan, 2022 Abstract The question of radio dichotomy in active galactic nuclei (AGNs) is still in debate, even though it has been discussed for more than 40 years. In order to solve this old riddle, we collect a sample of AGNs with optical B band and radio 6 cm wavelength data to analyze the radio loudness log R. Our results indicate a separation of
Xiao, Hubing +4 more
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Identifying Radio-active Galactic Nuclei among Radio-emitting Galaxies [PDF]
The Astrophysical Journal, 2021 Abstract Basing our analysis on ROGUE I, a catalog of over 32,000 radio sources associated with optical galaxies, we provide two diagnostics to select the galaxies where the radio emission is dominated by an active galactic nucleus (AGN), referred to in the paper as radio-AGNs. Each of these diagnostics can be applied independently.
D. Kozieł-Wierzbowska +6 more
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Low-luminosity radio-loud active galactic nuclei [PDF]
Proceedings of 8th European VLBI Network Symposium — PoS(8thEVN), 2007 I review observational properties of low power radio loud AGN. High resolution VLBI observations allow the estimate of the jet velocity and orientation with respect to the line of sight and the determination of the Doppler factor. These data reveal rich structures, including two-sided jets and secondary components. New results on 1144+35, a giant radio
Giovannini, Gabriele +1 more
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ENERGETICS AND LIFETIMES OF LOCAL RADIO ACTIVE GALACTIC NUCLEI [PDF]
The Astrophysical Journal, 2015 We present a model describing the evolution of Fanaroff-Riley type I and II radio AGN, and the transition between these classes. We quantify galaxy environments using a semi-analytic galaxy formation model, and apply our model to a volume-limited low redshift ($0.03 \leqslant z \leqslant 0.1$) sample of observed AGN to determine the distribution of jet
Ross J. Turner, Stanislav S. Shabala
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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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Ultrafast outflows in radio-loud active galactic nuclei [PDF]
Monthly Notices of the Royal Astronomical Society, 2014 Recent X-ray observations show absorbing winds with velocities up to mildly-relativistic values of the order of ~0.1c in a limited sample of 6 broad-line radio galaxies. They are observed as blue-shifted Fe XXV-XXVI K-shell absorption lines, similarly to the ultra-fast outflows (UFOs) reported in Seyferts and quasars.
Tombesi F. +7 more
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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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Compact radio cores in radio-quiet active galactic nuclei [PDF]
Astronomy & Astrophysics, 2016 Context. The mechanism of radio emission in radio-quiet (RQ) active galactic nuclei (AGNs) is still debated and might arise from the central AGN, from star formation activity in the host, or from either of these sources. A direct detection of compact and bright radio cores embedded in sources that are classified as RQ can unambiguously determine ...
MAINI, ALESSANDRO +4 more
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BeppoSAXView of Radio‐loud Active Galactic Nuclei [PDF]
The Astrophysical Journal, 2006 ApJ accepted, 33 pages, 6 ...
Grandi, Paola +2 more
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COSMIC EVOLUTION OF RADIO SELECTED ACTIVE GALACTIC NUCLEI IN THE COSMOS FIELD [PDF]
The Astrophysical Journal, 2009 18 pages, 14 figures, to appear in ...
SmolÄić, V. +16 more
openaire +7 more sources