Jet Formation and Collimation

Sauty, C.; Tsinganos, K.; Trussoni, E.

doi:10.1007/3-540-46025-x_3

Cited by 25 publications

(27 citation statements)

References 86 publications

(165 reference statements)

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“…Our model is constructed in the frame of general relativity using the metric of a central Schwarzschild black hole. It validates the classification of AGN proposed in Sauty et al (2001) where the classical MHD solutions were used with some additional features due to relativistic effects. In this study it was proposed that the inner regions of jets (spines) are collimated by an external denser medium in FR I and by the force of magnetic pinching in FR II.…”

Section: Discussionsupporting

confidence: 79%

Relativistic spine jets from Schwarzschild black holes

Méliani¹,

Sauty²,

Tsinganos³

et al. 2010

A&A

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Context. The two types of Fanaroff-Riley (FR) radio-loud galaxies, FR I and FR II, exhibit strong jets which have different properties. These differences may be associated to the central engine and/or the external medium. Aims. The AGN classification FR I and FR II can be linked to the rate of electromagnetic Poynting flux extraction from the inner corona of the central engine by the jet. The collimation results from the distribution of the total electromagnetic energy across the jet, as compared to the corresponding distribution of the thermal and gravitational energies. Methods. We use exact solutions of the fully relativistic magnetohydrodynamical (GRMHD) equations obtained by a nonlinear separation of the variables to study outflows from a Schwarzschild black hole corona. Results. A strong correlation is found between the jet features and the energetic distribution of the plasma of the inner corona, which may be related to the efficiency of the magnetic rotator. Conclusions. It is shown that observations of FR I and FR II jets may be partially constrained by our model for spine jets. The deceleration observed in FR I jets may be associated with a low magnetic efficiency of the central magnetic rotator and an important thermal confinement by the hot surrounding medium. Conversely, the strongly collimated and accelerated FR II outflows may be self-collimated by their own magnetic field because of the high efficiency of the central magnetic rotator.

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Section: Discussionsupporting

confidence: 79%

Relativistic spine jets from Schwarzschild black holes

Méliani¹,

Sauty²,

Tsinganos³

et al. 2010

A&A

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“…virial theorem), is channeled into the jet. Moreover, internal jet rotation is also implied in theoretical MHD models of jets as magnetized disk winds (e.g., Camenzind & Krockenberger 1992;Sauty et al 2002) and supported by recent observations of stellar jets (e.g., Coffey et al 2004). Knowledge of the underlying rotation law may then be used to estimate possible observable periods.…”

Section: Possible Periodic Driving Processes and Associated Constraintssupporting

confidence: 57%

Helical Motion and the Origin of QPO in Blazar-type Sources

Rieger

2005

Chin. J. Astron. Astrophys.

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Recent observations and analysis of blazar sources provide strong evidence for (i) the presence of significant periodicities in their lightcurves and (ii) the occurrence of helical trajectories in their radio jets. In scenarios, where the periodicity is caused by differential Doppler boosting effects along a helical jet path, both of these facts may be naturally tied together. Here we discuss four possible driving mechanisms for the occurrence of helical trajectories: orbital motion in a binary system, Newtonian-driven jet precession, internal jet rotation and motion along a global helical magnetic field. We point out that for non-ballistic helical motion the observed period may appear strongly shortened due to classical travel time effects. Finally, the possible relevance of the above mentioned driving mechanisms is discussed for Mkn 501, OJ 287 and AO 0235+16.

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“…(3) From a more theoretical point of view, intrinsic jet rotation is generally expected in magnetohydrodynamical (MHD) models for the formation and collimation of astrophysical jets (e.g. Begelman 1994;Sauty et al 2002). In such models, intrinsic rotation with speeds up to a considerable fraction of the velocity of light is a natural consequence of the assumption that the flow is centrifugally accelerated from the accretion disk.…”

Section: Introductionmentioning

confidence: 99%

Particle acceleration in rotating and shearing jets from AGN

Rieger¹,

Mannheim²

2002

A&A

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Abstract.We model the acceleration of energetic particles due to shear and centrifugal effects in rotating astrophysical jets. The appropriate equation describing the diffusive transport of energetic particles in a collisionless, rotating background flow is derived and analytical steady state solutions are discussed. In particular, by considering velocity profiles from rigid, over flat to Keplerian rotation, the effects of centrifugal and shear acceleration of particles scattered by magnetic inhomogeneities are distinguished. In the case where shear acceleration dominates, it is confirmed that power law particle momentum solutions f (p) ∝ p −(3+α) exist, if the mean scattering time τ c ∝ p α is an increasing function of momentum. We show that for a more complex interplay between shear and centrifugal acceleration, the recovered power law momentum spectra might be significantly steeper but flatten with increasing azimuthal velocity due to the increasing centrifugal effects. The possible relevance of shear and centrifugal acceleration for the observed extended emission in AGN is demonstrated for the case of the jet in the quasar 3C273.

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Jet Formation and Collimation

Cited by 25 publications

References 86 publications

Relativistic spine jets from Schwarzschild black holes

Relativistic spine jets from Schwarzschild black holes

Helical Motion and the Origin of QPO in Blazar-type Sources

Particle acceleration in rotating and shearing jets from AGN

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