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The jets observed to emanate from many compact accreting objects may arise from the twisting of a magnetic field threading a differentially rotating accretion disk which acts to magnetically extract angular momentum and energy from the…

Astrophysics · Physics 2009-11-10 R. V. E. Lovelace , P. R. Gandhi , M. M. Romanova

We propose a unified model for jet formation applicable to active galactic nuclei, young stellar objects, and X-ray binaries. In this model, the binding energy released from the accretion disk is primarily stored as turbulence rather than…

High Energy Astrophysical Phenomena · Physics 2026-05-11 Chun Xu

The magnetic field in an accretion disk is estimated assuming that all of the angular momentum within prescribed accretion disk radii is removed by a jet. The magnetic field estimated at the base of the jet is extrapolated to the blazar…

Astrophysics · Physics 2009-06-23 Geoffrey V. Bicknell , Jianke Li

Collimated outflows (jets) appear to be a ubiquitous phenomenon associated with the accretion of material onto a compact object. Despite this ubiquity, many fundamental physics aspects of jets are still poorly understood and constrained.…

High Energy Astrophysical Phenomena · Physics 2017-02-15 Gustavo Romero , Markus Boettcher , Sera Markoff , Fabrizio Tavecchio

Astrophysical jets are launched from strongly magnetized systems that host an accretion disk surrounding a central object. The origin of the jet launching magnetic field is one of the open questions for modeling the accretion-ejection…

High Energy Astrophysical Phenomena · Physics 2020-09-07 Giancarlo Mattia , Christian Fendt

We present numerical magnetohydrodynamic (MHD) simulations of a magnetized accretion disk launching trans-Alfvenic jets. These simulations, performed in a 2.5 dimensional time-dependent polytropic resistive MHD framework, model a resistive…

Astrophysics · Physics 2009-11-07 Fabien Casse , Rony Keppens

Jet formation is connected most probably with matter acceleration from the vicinity of rotating magnetized bodies. It is usually related to the mass outflows and ejection from accretion disks around black holes. Problem of jet collimation…

Astrophysics · Physics 2009-11-06 G. S. Bisnovatyi-Kogan , N. V. Ardeljan , S. G. Moiseenko

Powerful, highly collimated jets, surrounded by bipolar molecular outflows, are commonly observed near Young Stellar Objects (YSOs). In the usual theoretical picture of star formation, a jet is ejected from a magnetized accretion disk, with…

Astrophysics · Physics 2009-11-07 T. Lery , R. N. Henriksen , J. D. Fiege , T. P. Ray , A. Frank , F. Bacciotti

Theoretical models for the production of relativistic jets from active galactic nuclei predict that jet power arises from the spin and mass of the central black hole, as well as the magnetic field near the event horizon. The physical…

High Energy Astrophysical Phenomena · Physics 2015-06-23 G. Ghisellini , F. Tavecchio , L. Maraschi , A. Celotti , T. Sbarrato

One of the fundamental properties of astrophysical magnetic fields is their ability to change topology through reconnection and in doing so, to release magnetic energy, sometimes violently. In this work, we review recent results on the role…

High Energy Astrophysical Phenomena · Physics 2015-05-18 E. M. de Gouveia Dal Pino , G. Kowal , L. H. S. Kadowaki , P. Piovezan , A. Lazarian

We perform two-dimensional, axisymmetric, magnetohydrodynamic simulations of the collapse of a rotating star of 40 Msun and in the light of the collapsar model of gamma-ray burst. Considering two distributions of angular momentum, up to…

We present a self-similar, steady-state model describing both a magnetized accretion disc and a magnetohydrodynamic jet. We focus on the role of a hot corona in such a structure. This corona enables the disc to launch various types of jets.…

Astrophysics · Physics 2007-05-23 Fabien Casse , Jonathan Ferreira

Fast Magnetic Reconnection is currently regarded as an important process also beyond the solar system, specially in magnetically dominated regions of galactic and extragalactic sources like the surrounds of black holes and relativistic…

The theory of magnetically accelerated outflows and jets from accretion disks is reviewed at an introductory level, with special attention to problem areas like the launching conditions of the flow at the disk surface, stability of the…

Astrophysics · Physics 2007-05-23 H. C. Spruit

We carried out 2.5-dimensional resistive magnetohydrodynamic simulations to study the effects of magnetic diffusivity on magnetically driven mass accretion and jet formation. We found that (1) when the normalized magnetic diffusivity, is…

Astrophysics · Physics 2015-06-24 T. Kuwabara , K. Shibata , R. Matsumoto

Protostellar jets and winds are probably driven magnetocentrifugally from the surface of accretion disks close to the central stellar objects. The exact launching conditions on the disk, such as the distributions of magnetic flux and mass…

Astrophysics · Physics 2009-11-06 Ruben Krasnopolsky , Zhi-Yun Li , Roger D. Blandford

To investigate the formation mechanism of relativistic jets in active galactic nuclei and micro-quasars, we have developed a new general relativistic magnetohydrodynamic code in Kerr geometry. Here we report on the first numerical…

Astrophysics · Physics 2009-10-31 Shinji Koide , David L. Meier , Kazunari Shibata , Takahiro Kudoh

Measurements from astroparticle experiments, such as the 2017 flare associated with the source TXS 0506+056, indicate that blazars act as multi-messenger (MM; radiation and neutrinos) factories. Theoretically, the particle acceleration…

High Energy Astrophysical Phenomena · Physics 2025-02-18 E. M. de Gouveia Dal Pino , J. C. Rodríguez-Ramírez , M. V. del Valle

Recent numerical simulations of MHD jets from accretion disks are briefly reviewed with emphasis on the scaling law for jet speed and the role of magnetic reconnection in relation to time variability in accretion disks, jets, and flares. On…

Astrophysics · Physics 2007-05-23 Kazunari Shibata , Seiichiro Aoki

Based on theoretical arguments and quasi-stationary radiative MHD calculations, a model for an accretion-powered jet is presented. It is argued that accretion disks around BHs consist of 1) a cold, Keplerian-rotating and weakly magnetized…

Astrophysics · Physics 2009-11-07 A. Hujeirat , M. Livio , M. Camenzind , A. Burkert