Stability of Cloud Orbits in the Broad Line Region of Active Galactic Nuclei

Abstract

We investigate the global dynamic stability of spherical clouds in the Broad Line Region (BLR) of Active Galactic Nuclei (AGN), exposed to radial radiation pressure, gravity of the central black hole (BH), and centrifugal forces assuming the clouds adapt their size according to the local pressure. We consider both, isotropic and anisotropic light sources. In both cases, stable orbits exist also for very sub-Keplerian rotation for which the radiation pressure contributes substantially to the force budget. We demonstrate that highly eccentric, very sub-Keplerian stable orbits may be found. This gives further support for the model of Marconi et al. 2008, who pointed out that black hole masses might be significantly underestimated if radiation pressure is neglected. That model improved the agreement between black hole masses derived in certain active galaxies based on BLR dynamics, and black hole masses derived by other means in other galaxies by inclusion of a luminosity dependent term. For anisotropic illumination, energy is conserved for averages over long time intervals, only, but not for individual orbits. This leads to Rosetta orbits that are systematically less extended in the direction of maximum radiation force. Initially isotropic relatively low column density systems would therefore turn into a disk when an anisotropic AGN is switched on.

7 pages, 4 fig.s, accepted by MNRAS, some text was missing - corrected

References in corpus (10)

• The Lick AGN Monitoring Project: Broad-Line Region Radii and Black Hole Masses from Reverberation Mapping of Hbeta
• The effect of radiation pressure on virial black hole mass estimates and the case of Narrow Line Seyfert 1 galaxies
• What broad emission lines tell us about how active galactic nuclei work
• Diverse Broad Line Region Kinematic Signatures From Reverberation Mapping
• Orientation dependency of broad-line widths in quasars and consequences for black-hole mass estimation
• First Results from the Lick AGN Monitoring Project: The Mass of the Black Hole in Arp 151
• On the observed distributions of black hole masses and Eddington ratios from radiation pressure corrected virial indicators
• Contribution of a Disk Component to Single Peaked Broad Lines of Active Galactic Nuclei
• Evidence for a Type 1/Type 2 dichotomy in the correlation between quasar optical polarization and host galaxy/extended emission position angles
• A simplified global solution for an advection-dominated accretion flow

Cited by in corpus (18)

• How frequent are close supermassive binary black holes in powerful jet sources?
• On the Observational Difference Between the Accretion Disk-Corona Connections among Super- and Sub-Eddington Accreting Active Galactic Nuclei
• The picture of BLR in 2.5-D FRADO: Dynamics & Geometry
• The effects of irradiation on the cloud evolution in active galactic nuclei
• SDSS J075101.42+291419.1: A Super-Eddington Accreting Quasar with Extreme X-ray Variability
• Magnetohydrodynamic stability of broad line region clouds
• Dynamics of gas and dust clouds in active galactic nuclei
• On the dynamics of clouds in the broad-line region of AGNs with an ADAF atmosphere
• Correlation between Line Width and Line Flux of Double-Peaked Broad Halpha of 3C390.3
• Measuring the Virial Factor in SDSS DR5 Quasars with Redshifted H$\beta$ and Fe ii Broad Emission Lines
• More Evidence for the Intermediate Broad Line Region of the Mapped AGN PG 0052+251
• Are broad optical balmer lines from central accretion disk in PG 1613+658?
• Measuring the Virial Factor in SDSS DR7 AGNs with Redshifted H$\beta$ and H$\alpha$ Broad Emission Lines
• Differential interferometry of close binary of supermassive black holes in an elliptical configuration
• Effect of the drag force on the orbital motion of the broad-line region clouds
• Kinematics and Structure of Clumps in Broad-line Regions in Active Galactic Nuclei
• Dynamics of an ensemble of clumps embedded in a magnetized ADAF
• Thermal Conduction in Clumpy Disks and BLR clouds