Query : 2001A&A...369..308F

2001A&A...369..308F - Astronomy and Astrophysics, volume 369, 308-322 (2001/4-1)

Magnetically driven superluminal motion from rotating black holes. Solution of the magnetic wind equation in Kerr metric.


Abstract (from CDS):

We have investigated magnetically driven superluminal jets originating from rotating black holes. The stationary, general relativistic, magnetohydrodynamic wind equation along collimating magnetic flux surfaces has been solved numerically. Our jet solutions are calculated on a global scale of a spatial range from several to several 1000 gravitational radii. Different magnetic field geometries were investigated, parameterized by the shape of the magnetic flux surface and the magnetic flux distribution. For a given magnetic flux surface we obtain the complete set of physical parameters for the jet flow. In particular, we apply our results to the Galactic superluminal sources GRS1915+105 and GRO1655-40. Motivated by the huge size indicated for the Galactic superluminal knots of about 109 Schwarzschild radii, we point out the possibility that the jet collimation process in these sources may be less efficient and therefore intrinsically different to the AGN. Our results show that the observed speed of more than 0.9c can be achieved in general by magnetohydrodynamic acceleration. The velocity distribution along the magnetic field has a saturating profile. The asymptotic jet velocity depends either on the plasma magnetization (for a fixed field structure) or on the magnetic flux distribution (for fixed magnetization). The distance where the asymptotic velocity is reached, is below the observational resolution for GRS 1915+105 by several orders of magnitude. Further, we find that highly relativistic speeds can be reached also for jets not emerging from a region close to the black hole, if the flow magnetization is sufficiently large. The plasma temperature rapidly decreases from about 1010K at the foot point of the jet to about 106 K at a distance of 5000 gravitational radii from the source. Temperature and the mass density follow a power law distribution with the radius. The jet magnetic field is dominated by the toroidal component, whereas the velocity field is dominated by the poloidal component.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - Black hole physics - MHD - stars: mass loss - ISM: jets and outflows - galaxies: jets

CDS comments: p.318: 2C 273 misprint for 3C 273

Simbad objects: 3

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Number of rows : 3
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
1 3C 273 BLL 12 29 06.6998257176 +02 03 08.597629980   13.05 14.830 14.11   ~ 5584 1
2 V* V1033 Sco HXB 16 54 00.137 -39 50 44.90   15.20 14.2 16.14   F5IV 1793 1
3 Granat 1915+105 HXB 19 15 11.55576 +10 56 44.9052           ~ 2453 0

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