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Related papers: High Eddington quasars as discovery tools: current…

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We continue our study of the spectral energy distributions (SEDs) of 11 AGN at 1.5 < z < 2.2, with optical-NIR spectra, X-ray data and mid-IR photometry. In a previous paper we presented the observations and models; in this paper we explore…

High Energy Astrophysical Phenomena · Physics 2016-12-14 James S. Collinson , Martin J. Ward , Hermine Landt , Chris Done , Martin Elvis , Jonathan C. McDowell

We show how accretion rate governs the physical properties of a sample of unobscured broad-line, narrow-line, and lineless active galactic nuclei (AGNs). We avoid the systematic errors plaguing previous studies of AGN accretion rate by…

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

Quasars are rapidly accreting supermassive black holes at the center of massive galaxies. They display a broad range of properties across all wavelengths, reflecting the diversity in the physical conditions of the regions close to the…

Astrophysics of Galaxies · Physics 2015-06-22 Yue Shen , Luis C. Ho

We perform an exploratory study of the physical properties of accretion flows and jets in low-luminosity active galactic nuclei (LLAGNs) by modeling the spectral energy distributions (SEDs) of 12 LLAGNs in low-ionization nuclear…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Rodrigo S. Nemmen , Thaisa Storchi-Bergmann , Michael Eracleous

Here we discuss the effects of strong gravity that can be observed in electromagnetic spectra of active galactic nuclei (AGN). According to the unification model of an AGN, there is a supermassive black hole ($10^7 - 10^9 M_\odot$) in its…

Astrophysics · Physics 2009-06-25 P. Jovanović , L. Č. Popović

This paper reports results of the third-year campaign of monitoring super-Eddington accreting massive black holes (SEAMBHs) in active galactic nuclei (AGNs) between 2014-2015. Ten new targets were selected from quasar sample of Sloan…

The broadband spectral energy distribution (SED) of Active Galactic Nuclei (AGN) is investigated for a well-selected sample composed of $23$ Seyfert 1 galaxies observed simultaneously in the optical/UV and X-ray bands with the Neil Gehrels…

High Energy Astrophysical Phenomena · Physics 2019-06-12 Huaqing Cheng , Weimin Yuan , He-Yang Liu , A. A. Breeveld , Chichuan Jin , Bifang Liu

We perform one-dimensional radiation hydrodynamical simulations to solve accretion flows onto massive black holes (BHs) with a very high rate. Assuming that photon trapping limits the luminosity emerging from the central region to…

High Energy Astrophysical Phenomena · Physics 2016-09-07 Yuya Sakurai , Kohei Inayoshi , Zoltán Haiman

We have calculated stationary models for accretion disks around super-massive black holes in galactic nuclei. Our models show that below a critical mass flow rate of ~3 10**-3 M_Edd advection will dominate the energy budget while above that…

Astrophysics · Physics 2009-11-07 T. Beckert , W. J. Duschl

We investigate the origin of the soft X-ray excess component in Seyfert galaxies observed when their luminosity exceeds 0.1% of the Eddington luminosity ($L_{\mathrm{Edd}}$). The evolution of a dense blob in radiatively inefficient…

High Energy Astrophysical Phenomena · Physics 2020-10-28 Taichi Igarashi , Yoshiaki Kato , Hiroyuki R. Takahashi , Ken Ohsuga , Yosuke Matsumoto , Ryoji Matsumoto

The supermassive black holes in active galactic nuclei (AGN) and stellar-mass black holes in X-ray binaries (XRBs) are believed to work in a similar way. While XRBs evolve rapidly and several sources have undergone a few complete cycles…

Astrophysics of Galaxies · Physics 2017-07-26 Jiri Svoboda , Matteo Guainazzi , Andrea Merloni

The geometry and kinematics of the broad-line region (BLR) in AGNs are still unclear, which is crucial for studying the physics and evolution of supermassive black holes (SMBHs) and AGNs. The broad-line profile provides valuable information…

Astrophysics of Galaxies · Physics 2024-12-25 Jiancheng Wu , Qingwen Wu , Kaixing Lu , Xinwu Cao , Xiangli Lei , Mengye Wang , Xiao Fan

Active galactic nuclei (AGN) are complex phenomena. At the heart of an AGN is a relativistic accretion disk around a spinning supermassive black hole (SMBH) with an X-ray emitting corona and, sometimes, a relativistic jet. On larger scales,…

High Energy Astrophysical Phenomena · Physics 2016-05-25 Christopher S. Reynolds

The spectra of quasars and NLS1 galaxies show surprising similarity in their spectral shape. They seem to scale only with the accretion rate. This is in contradiction with the simple expectations from the standard disk model which predicts…

Astrophysics · Physics 2009-11-10 B. Czerny , M. Nikolajuk , A. Rozanska , A. -M. Dumont , Z. Loska , P. T. Zycki

X-ray variability of active galactic nuclei (AGN) and black hole binaries can be analysed by means of the power spectral density (PSD). The break observed in the power spectrum defines a characteristic variability timescale of the accreting…

High Energy Astrophysical Phenomena · Physics 2015-06-04 W. Ishibashi , T. J. -L. Courvoisier

We report first results from a large project to measure black hole (BH) mass in high accretion rate active galactic nuclei (AGNs). Such objects may be different from other AGNs in being powered by slim accretion disks and showing saturated…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 P. Du , C. Hu , K. -X. Lu , F. Wang , J. Qiu , Y. -R. Li , J. -M. Bai , S. Kaspi , H. Netzer , J. -M. Wang

We present an investigation into how well the properties of the accretion flow onto a supermassive black hole may be coupled to those of the overlying hot corona. To do so, we specifically measure the characteristic spectral index, Gamma,…

A wide-frequency radio study of Active Galactic Nuclei (AGN) is crucial to evaluate the intervening radiative mechanisms responsible for the observed emission and relate them with the underlying accretion physics. We present wide frequency…

Changing-look active galactic nuclei (CLAGNs) show the appearance and disappearance of broad emission lines in their UV/optical spectra on timescales of months to decades. Here, we investigate how CL transitions depend on several AGN…

Astrophysics of Galaxies · Physics 2025-01-08 A. Jana , C. Ricci , M. J. Temple , H. -K. Chang , E. Shablovinskaya , B. Trakhtenbrot , Y. Diaz , D. Ilic , P. Nandi , M. Koss