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Broad emission lines are the most characteristic features in the spectra of active galaxies. They mostly show either a single-peaked or double-peaked profiles; and originate from a complex dynamics of the likely discrete clouds moving in a…

Astrophysics of Galaxies · Physics 2022-07-20 Mohammad-Hassan Naddaf , Bozena Czerny

The dynamics of the Broad Line Region (BLR) in Active galaxies is an open question, direct observational constraints suggest a predominantly Keplerian motion, with possible traces of inflow or outflow. In this paper we study in detail the…

Astrophysics of Galaxies · Physics 2021-10-20 Mohammad-Hassan Naddaf , Bozena Czerny , Ryszard Szczerba

The broad-line region (BLR) of active galactic nuclei (AGNs) traces gas close to the central supermassive black hole (BH). Recent reverberation mapping (RM) and interferometric spectro-astrometry data have enabled detailed investigations of…

In this work we analyze a sample of AGN spectra, selected from the 6th Data Release of the Sloan Digital Sky Survey, exploiting a generalized technique of line profile analysis, designed to take into account the whole profiles of their…

Astrophysics · Physics 2011-02-11 G. La Mura , F. Di Mille , S. Ciroi , L. Č. Popović , P. Rafanelli

In Failed Radiatively Accelerated Dusty Outflow (FRADO) model which provides the source of material above the accretion disk (AD) as an option to explain the formation mechanism of Broad Line Region (BLR) in AGNs, the BLR inner radius…

High Energy Astrophysical Phenomena · Physics 2020-06-05 Mohammad-Hassan Naddaf , Bozena Czerny , Ryszard Szczerba

We investigate orbital motion of spherical, pressure-confined clouds in the broad-line region (BLR) of active galactic nuclei (AGN). The combined influence of gravity of the central object and the non-isotropic radiation of the central…

Astrophysics of Galaxies · Physics 2015-06-23 Fazeleh Khajenabi

Broad Emission Lines are the most characteristic features of Active Galaxies, but the mechanism of creating a medium able to emit these intense lines is not quite clear. Observations clearly indicate that the motion of the material is…

Astrophysics of Galaxies · Physics 2019-09-19 Bozena Czerny

The effective size of Broad Line Region (BLR), so-called the BLR radius, in galaxies with active galactic nuclei (AGN) scales with the source luminosity. Therefore by determining this location either observationally through reverberation…

Astrophysics of Galaxies · Physics 2020-04-07 Mohammad-Hassan Naddaf , Bozena Czerny , Ryszard Szczerba

The nuclei of a wide class of active galaxies emit broad emission lines with widths at half maximum (FWHM) in the range $10^{3}-10^{4}$ km s$^{-1}$. This spread of widths is not solely a consequence of the range of the luminosities of these…

Astrophysics · Physics 2009-10-30 C. M. Rudge , D. J. Raine

Many studies have considered the roles of clouds, outflows, and turbulence in producing the broad emission and absorption lines in the spectra of active galactic nuclei (AGNs). However, these are often treated as separate or even competing…

Astrophysics of Galaxies · Physics 2019-12-10 Tim Waters , Hui Li

In order to contribute to the general effort aiming at the improvement of our knowledge about the physical conditions within the Broad Line Region (BLR) of Active Galactic Nuclei (AGN), here we present the results achieved by our analysis…

Astrophysics · Physics 2009-03-12 G. La Mura , L. Č. Popović , S. Ciroi , P. Rafanelli , D. Ilić

The broad-line region (BLR) of active galactic nuclei (AGN) is an essential component, yet its small size keeps its origin, structure, and kinematics uncertain. Infrared interferometry with VLTI/GRAVITY is now resolving BLR-scale emission,…

Astrophysics of Galaxies · Physics 2026-03-12 Keiichi Wada , Tohru Nagao , Taro Shimizu , Daryl Joe D. Santos , Jinyi Shangguan , Richard Davies

The variable continuum emission of an active galactic nucleus (AGN) produces corresponding responses in the broad emission lines, which are modulated by light travel delays, and contain information on the physical properties, structure, and…

Astrophysics of Galaxies · Physics 2023-11-08 Sara Rosborough , Andrew Robinson , Triana Almeyda , Madison Noll

The spectra of active galactic nuclei exhibit broad-emission lines that presumably originate in the Broad-Line Region (BLR) with gaseous-dusty clouds in a predominantly Keplerian motion around the central black hole. Signatures of both…

High Energy Astrophysical Phenomena · Physics 2022-06-01 Ana Laura Müller , Mohammad-Hassan Naddaf , Michal Zajaček , Bożena Czerny , Anabella Araudo , Vladimír Karas

This paper presents a preliminary investigation into the influence of radial behavior of disk outflow on the structure and dynamics of the broad line region (BLR) in active galactic nuclei (AGNs), with the emphasis on how the mass ejection…

Astrophysics of Galaxies · Physics 2024-12-30 Mohammad Hassan Naddaf

We derive a theoretical relation between $R_{BLR}$, the size of the broad-emission-line region of active galactic nuclei, and the observed soft X-ray luminosity and spectrum. We show that in addition to the well known $R_{BLR}\sim L^{1/2}$…

Astrophysics · Physics 2007-05-23 Amri Wandel

We study orbit of a pressure-confined cloud in the broad-line region (BLR) of active galactic nuclei (AGNs) when the combined effects of the central gravity and anisotropic radiation pressure and the drag force are considered. Physical…

Astrophysics of Galaxies · Physics 2015-06-02 Mohsen Shadmehri

The spectral variability of active galactic nuclei (AGN) is one of their key features that enables us to study in more details the structure of AGN emitting regions. Especially, the broad line profiles, that vary both in flux and shape,…

Astrophysics of Galaxies · Physics 2016-01-20 D. Ilic , L. C. Popovic , A. I. Shapovalova , A. N. Burenkov , V. H. Chavushyan , A. Kovacevic

(Abridged) We investigate the observational characteristics of BLR geometries in which the BLR clouds bridge the gap, both in distance and scale height, between the outer accretion disc and the hot dust, forming an effective surface of a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 M. R. Goad , K. T. Korista , A. J. Ruff

The origin of the broad-line region (BLR) clouds in active galactic nuclei is still under discussion. We develop a scenario in which the clouds in the outer, less ionized part of the BLR are launched by the radiation pressure acting on…

Astrophysics of Galaxies · Physics 2024-01-10 Mohammad Hassan Naddaf , Bozena Czerny
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