Results 11 to 20 of about 217,086 (193)
The Correlation between X-ray spectral slope and FeKalpha line energy in radio-quiet active galactic nuclei [PDF]
Astrophys.J. 581 (2002) L71-L76, 2002 A significant correlation between FeKalpha line energy and X-ray spectral slope has been discovered among radio-quiet active galactic nuclei. The ionization stage of the bulk of the FeKalpha emitting material is not the same in all active galactic nuclei and is related to the shape of the X-ray continua.
arxiv +1 more source
The Astrophysical Journal, 2023 The variability of submillimeter emission provides a useful tool to probe the accretion physics in low-luminosity active galactic nuclei. We accumulate four years of observations using the Submillimeter Array for Centaurus A, NGC 4374, NGC 4278, and NGC ...
Bo-Yan Chen +7 more
doaj +1 more source
Origin of Radio Emission from Nearby Low-Luminosity Active Galactic Nuclei [PDF]
Astrophys.J.621:130-138,2005, 2004 We use the observational data in radio, optical and X-ray wavebands, for a sample of active galactic nuclei (AGNs) with measured black hole masses, to explore the origin of radio emission from nearby low-luminosity active galactic nuclei (LLAGNs). We find that the radio luminosities are higher than the maximal luminosities expected from the ADAF model,
arxiv +1 more source
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
Recurrent radio activity in active galactic nuclei
EPJ Web of Conferences, 2012 There has been a growing body of persuasive evidence to indicate that AGN activity, powered by mass accretion onto a supermassive black hole, can involve multiple episodes.
Jamrozy M.
doaj +1 more source
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
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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Very long baseline interferometry observation of the triple AGN candidate J0849+1114 [PDF]
A&A 630, L5 (2019), 2019 In the hierarchical structure formation model, galaxies grow through various merging events. Numerical simulations indicate that the mergers can enhance the activity of the central supermassive black holes in the galaxies. Pfeifle et al. (2019a) identified a system of three interacting galaxies, J0849$+$1114, and provided multiwavelength evidence of ...
arxiv +1 more source
On the Relationship Between Radio Emission and Black Hole Mass in Galactic Nuclei [PDF]
Astrophys.J.564:120-132,2002, 2001 We use a comprehensive database of black hole masses and nuclear luminosities to investigate the relationship between radio emission and black hole mass. Our sample covers a wide range of nuclear activity, from nearby inactive nuclei to classical Seyfert 1 nuclei and luminous quasars.
arxiv +1 more source
Radio-to-gamma-ray synchrotron and neutrino emission from proton-proton interactions in active galactic nuclei [PDF]
, 2020 We explore possible physical origin of correlation between radio wave and very-high-energy neutrino emission in active galactic nuclei (AGN), suggested by recently reported evidence for correlation between neutrino arrival directions and positions of brightest radio-loud AGN.
arxiv +1 more source