Accueil > Séminaires d’Astrophysique > Relativistic hydrodynamic and Magnetohydrodynamic numerical simulations of jet in GRB and radio galaxies FRI, FRII

 

Relativistic hydrodynamic and Magnetohydrodynamic numerical simulations of jet in GRB and radio galaxies FRI, FRII

Zakaria Meliani (Laboratoire de L’Univers et ses theories - LUTh , Paris)

Par Stephane Charpinet - 23/01/2008

 

Séminaires d’Astrophysique

de l’Observatoire Midi-Pyrénées


Séminaire de

Zakaria MELIANI

 (Laboratoire de L’Univers et ses theories - LUTh , Paris)

Jeudi 24 Janvier 2008 à 11h

CESR


Relativistic hydrodynamic and Magnetohydrodynamic numerical simulations of jet in GRB and radio galaxies FRI, FRII

In the first part, I will present the numerical investigation of the various evolutionary phases in the interaction of a relativistic shell with its surrounding cold Interstellar Medium (ISM). We do this for both 1D isotropic as well as full 2D jetlike fireball models. In such jetlike GRB models, I will discuss the differences with the 1D isotropic GRB equivalents. These are mainly due to thermally induced sideways expansions of both the shocked shell and shocked ISM regions. We found that the propagating 2D ultrarelativistic shell does not accrete all the surrounding medium located within its initial opening angle. Part of this ISM matter gets pushed away laterally and forms a wide bow-shock configuration with swirling flow patterns trailing the thin shell. The resulting shell deceleration is quite different from that found in isotropic GRB models. As long as the lateral shell expansion is merely due to ballistic spreading of the shell, isotropic and 2D models agree perfectly. As thermally induced expansions eventually lead to significantly higher lateral speeds, the 2D shell interacts with comparably more ISM matter and decelerates earlier than its isotropic counterpart. The second part, Different model of jet deceleration in FRI radio galaxy we presented. The first, we study relativistic jet propagation in radio galaxies, where the jets encounter a sudden jump in the external medium density. We use this setup to analyze the deceleration of jets in FR I radio galaxies, where the jet is relativistic at pc scales, and subrelativistic at kpc scales. Variations in ISM density could explain sudden transitions in jet propagation behavior. The second, We explore the stability of stratified, rotating, relativistic two-component jets, in turn embedded in static interstellar medium. Also we analyze the effects of two-component in jet deceleration. In the end, I will present the effects of the helical magnetic field on the jet stabilization and the formation of the cocoon.

 

 

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Bibliotheque

Laboratoire Astrophysique de Toulouse - Tarbes (UMR5572)

CNRS (Midi-Pyrénées)

Univ. Paul Sabatier

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