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Related papers: Peculiar AGNs from the INTEGRAL and RXTE data

200 papers

We present results of recurrence analysis of 46 active galactic nuclei (AGN) using light curves from the 157-month catalog of the Swift Burst Alert Telescope (BAT) in the 14-150 keV band. We generate recurrence plots and compute recurrence…

High Energy Astrophysical Phenomena · Physics 2022-11-28 R. A. Phillipson , M. S. Vogeley , P. T. Boyd

The mechanism of radio emission in radio-quiet (RQ) active galactic nuclei (AGN) 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…

Astrophysics of Galaxies · Physics 2016-04-06 Alessandro Maini , Isabella Prandoni , Ray P. Norris , Gabriele Giovannini , Lee R. Spitler

In this letter we present the primary continuum parameters, the photon index Gamma and the high energy cut-off Ec, of 41 type-1 Seyfert galaxies extracted from the INTEGRAL complete sample of AGN. We performed a broad band (0.3-100 keV)…

High Energy Astrophysical Phenomena · Physics 2015-06-18 A. Malizia , M. Molina , L. Bassani , J. B. Stephen , A. Bazzano , P. Ubertini , A. J. Bird

The dichotomy between radio-loud (RL) and radio-quiet (RQ) active galactic nuclei (AGN) is thought to be intrinsically related to radio jet production. This difference may be explained by the presence of a strong magnetic field (B-field)…

Active Galactic Nuclei (AGN) are ideal sources for multi-wavelength studies as their emission can cover almost 20 orders of magnitude in frequency from the radio to the gamma-ray band. After reviewing their basic properties, I will assess…

Astrophysics · Physics 2007-05-23 Paolo Padovani

Active Galactic Nuclei (AGN) can be probed by at different regions of the electromagnetic spectrum: e.g., radio observations reveal the nature of their relativistic jets and their magnetic fields, and complementarily, X-ray observations…

We have analyzed the NVSS and SUMSS data at 1.4 GHz and 843 MHz for a well defined complete sample of hard X-ray AGN observed by INTEGRAL. A large number (70/79) of sources are detected in the radio band, showing a wide range of radio…

High Energy Astrophysical Phenomena · Physics 2015-06-23 F. Panessa , A. Tarchi , P. Castangia , E. Maiorano , L. Bassani , G. Bicknell , A. Bazzano , A. J. Bird , A. Malizia , P. Ubertini

The question of radio dichotomy in the active galactic nuclei (AGNs) is still in debate even it has been proposed for more than forty years. In order to solve the old riddle, we collect a sample of AGNs with optical $B$ band and radio 6cm…

Astrophysics of Galaxies · Physics 2022-02-16 Hubing Xiao , Jingtian Zhu , Liping Fu , Shaohua Zhang , Junhui Fan

Accreting supermassive black holes at the centres of galaxies are the engine of active galactic nuclei (AGN). X-ray light curves of unabsorbed AGN show dramatic random variability on timescales ranging from seconds to years. The power…

High Energy Astrophysical Phenomena · Physics 2025-10-29 Mehdy Lefkir , Simon Vaughan , Mike Goad , Daniela Huppenkothen , Phil Uttley

Hard X-ray ($\geq 10$ keV) observations of Active Galactic Nuclei (AGN) can shed light on some of the most obscured episodes of accretion onto supermassive black holes. The 70-month Swift/BAT all-sky survey, which probes the 14-195 keV…

(Abridged) In this article, we discuss the state of ``AGN feedback'' in radio-quiet (RQ) AGN. This study involves heterogeneous samples of nearby Seyfert and LINER galaxies as well as QSOs that have been observed at low radio frequencies…

Astrophysics of Galaxies · Physics 2023-02-15 Preeti Kharb , Silpa Sasikumar

Broadband X-ray spectroscopy of the X-ray emission produced in the coronae of active galactic nuclei (AGN) can provide important insights into the physical conditions very close to their central supermassive black holes. The temperature of…

Analysis of the frequency and physical properties of galaxies with star-formation and AGN activity in different environments in the local universe is a cornerstone for understanding structure formation and galaxy evolution. We have built a…

Astrophysics · Physics 2008-11-26 Pietro Reviglio , David J. Helfand

We present a broadband X-ray analysis of a new homogeneous sample of 95 active galactic nuclei (AGN) from the 22-month Swift/BAT all-sky survey. For this sample we treated jointly the X-ray spectra observed by XMM-Newton and INTEGRAL…

High Energy Astrophysical Phenomena · Physics 2015-11-20 A. A. Vasylenko , V. I. Zhdanov , E. V. Fedorova

The energy coupling efficiency of active galactic nucleus (AGN) outbursts is known to {vary} significantly with factors including the jet kinetic power, duration of the outburst, and properties of the host galaxy group or cluster. As such,…

Astrophysics of Galaxies · Physics 2025-01-08 Benjamin Quici , Ross J. Turner , Nicholas Seymour , Natasha Hurley-Walker

The determination of the broad (0.1-100 keV) spectra of active galaxies is crucial for understanding and discriminating among emission models, for estimating the properties of the Comptonising/reflecting region around the central black hole…

High Energy Astrophysical Phenomena · Physics 2013-02-12 Manuela Molina , L. Bassani , A. Malizia , A. Bazzano , P. Ubertini , A. J. Bird

The ionizing fluxes from quasars and other active galactic nuclei (AGN) are critical for interpreting their emission-line spectra and for photoionizing and heating the intergalactic medium (IGM). Using far-ultraviolet spectra from the…

Astrophysics of Galaxies · Physics 2015-06-22 Matthew L. Stevans , J. Michael Shull , Charles W. Danforth , Evan M. Tilton

Accretion discs in AGN may be associated with coronal gas, as suggested by their X-ray emission. Stellar coronal emission includes radio emission, and AGN corona may also be a significant source for radio emission in radio quiet (RQ) AGN.…

Astrophysics of Galaxies · Physics 2016-04-08 Igor Raginski , Ari Laor

Active Galactic Nuclei (AGN) are highly energetic astrophysical sources powered by accretion onto supermassive black holes in galaxies, which present unique observational signatures covering the full electromagnetic spectrum (and more) over…

High Energy Astrophysical Phenomena · Physics 2023-04-05 Stefano Bianchi , Vincenzo Mainieri , Paolo Padovani

We present results of a high-resolution soft X-ray (0.2-2 keV) spectroscopic study of a sample of 69 nearby obscured Active Galactic Nuclei (AGN) observed with the Reflection Grating Spectrometer (RGS) on board XMM-Newton. This is the…

Astrophysics · Physics 2008-11-26 Matteo Guainazzi , Stefano Bianchi