Results 51 to 60 of about 23,272 (235)
On the dust geometry in radio-loud active galactic nuclei [PDF]
Monthly Notices of the Royal Astronomical Society, 2010 17 pages, 12 figures, accepted by ...
Catherine L. Buchanan +2 more
openaire +4 more sources
The Astrophysical Journal, 2023 Based on our dedicated Swift monitoring program, MOMO, OJ 287 is one of the best-monitored blazars in the X-ray–UV–optical regime. Here, we report results from our accompanying, dense, multifrequency (1.4–44 GHz) radio monitoring of OJ 287 between 2015 ...
S. Komossa +14 more
doaj +1 more source
Compact radio cores in radio-quiet active galactic nuclei [PDF]
, 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
Alessandro Maini +4 more
semanticscholar +1 more source
Active Galactic Nuclei, Radio Jets and Acceleration of UHECRs [PDF]
Nuclear Physics B - Proceedings Supplements, 2009 We present the general properties of the Active Galactic Nuclei (AGNs) and discuss the origin and structure of jets that are associated to a fraction of these objects. We then we address the problems of particle acceleration at highly relativistic energies and set limits on the luminosity of AGN jets for being origin of UHECRs.
openaire +3 more sources
Overview and Status of the International Celestial Reference Frame as Realized by VLBI
Universe, 2022 Accurate measurement of angular positions on the sky requires a well-defined system of reference that is realized with accessible objects. The purpose of this study is to review the international standard realization of such a system, the International ...
Aletha de Witt +3 more
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Observational Tests of Active Galactic Nuclei Feedback: An Overview of Approaches and Interpretation [PDF]
GalaxiesGrowing supermassive black holes (Active Galactic Nuclei; AGN) release energy with the potential to alter their host galaxies and larger-scale environment; a process named “AGN feedback”.
C. Harrison, C. Ramos Almeida
semanticscholar +1 more source
Quasars and active galactic nuclei: high resolution radio imaging. [PDF]
Proceedings of the National Academy of Sciences, 1995 The 12th colloquium in the series organized by the National Academy of Sciences, Quasars and Active Galactic Nuclei: High Resolution Radio Imaging, was held at the NAS Beckman Center in Irvine, California, on March 24 and 25, 1995. The meeting brought together 138 scientists from 17 countries. The majority of the participants were radio astronomers,
Cohen, Marshall H. +1 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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The bulk kinetic power of radio jets in active galactic nuclei [PDF]
Monthly Notices of the Royal Astronomical Society, 2009 Based on the K nigl's inhomogeneous jet model, we estimate the jet parameters, such as bulk Lorentz factor $ $, viewing angle $ $ and electron number density $n_{\rm e}$ from radio VLBI and X-ray data for a sample of active galactic nuclei (AGNs) assuming that the X-rays are from the jet rather than the intracluster gas.
Minfeng Gu, Xinwu Cao, Dong-Rong Jiang
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Searching for Quasiperiodic Modulations in γ-Ray Active Galactic Nuclei [PDF]
Astrophysical Journal, 2020 We perform a systematic search of quasiperiodic variabilities in γ-ray active galactic nuclei in the third Fermi Large Area Telescope source catalog (3FGL).
Peng-fei Zhang +4 more
semanticscholar +1 more source