English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

The accretion of hot slowly rotating gas onto a supermassive black hole isconsidered. Rotation velocities at the Bondi radius r_B are small in comparisonwith speed of sound c_s. The centrifugal barrier at a depth r_c = l^2/G M_BH <<r_B hinders supersonic accretion. We take into account saturated electronthermal conductivity and Bremsstrahlung energy losses of two temperature plasmafor density and temperature near the Bondi radius similar to those observed inM87 galaxy. Joint action of electron thermal conductivity and free-freeradiation leads to the effective cooling of accreting plasma and formation ofthe subsonic settling of accreting gas above the zone of a centrifugal barrier.A toroidal condensation and a hollow funnel that separates the torus from theblack hole emerge near the barrier. The barrier divides the flow into tworegions: (1) the settling zone with slow subKeplerian rotation and (2) the zonewith rapid supersonic nearly Keplerian rotation. Existence of the centrifugalbarrier leads to significant decrease of the accretion rate dM/dt in comparisonwith the critical Bondi solution for gamma=5/3. Shear instabilities in thetorus and related friction cause the gas to spread slowly in the equatorialplane in two directions. As a result, outer (r>r_c) and inner (r<r_c) disks areformed. The gas enters the zone of the internal ADAF flow along the accretiondisk (r<r_c). Since the angular momentum is conserved, the outer disk removesoutward an excess of angular momentum along with part of the matter fallinginto the torus. Such outer Keplerian disk was observed by Hubble SpaceTelescope around the nucleus of the M87 galaxy in the optical emission lines.Turbulence causes rotation. We discuss the characteristic times during whichthe turbulence should lead to the changes in the orientation of the torus,accretion disk and, possibly, of the jet.

Supermassive Black Hole in an Elliptical Galaxy: Accretion of a Hot Gas with a Low but Finite Angular Momentum