31/5/2007 Journée des Thèses 1

Models of Microquasars

Gareth Murphy Laboratoire Astrophysique de Grenoble

P.O. Petrucci, C. Zanni, T. Boutelier, J. Ferreira, F. Casse, G. Henri, A. Marcowith

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Plan

1.  Background 2.  Postdoc

–  What is a microquasar? –  What is the two flow model?

3.  Future

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Background •  BE University College Dublin •  PhD “Three-dimensional models of

astrophysical magnetohydrodynamical jets” at Dublin Institute for Advanced Studies + Trinity College, Dublin

•  ANR Postdoc Sherpas LAOG numerical models for microquasars

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What is a microquasar? •  A microquasar is an X-ray binary

containing a compact object: either a black hole or a neutron star which features jets or outflows at relativistic speeds (Mirabel et Rodriguez 1992)

•  Microquasar observations show both: –  Spatially resolved images of

mildly relativistic jets –  Episodic ejections with

highly relativistic speeds •  E.g. GRS-1915+105, SS433,

ScoX-1

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Results: Simulation BL1

•  Blob of gas is injected in pressure equilibrium with its surroundings.

•  No added thermal pressure.

•  Little field line distortion. •  Little diffusion of injected

material

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Results: Simulation BL2

•  Blob of gas is injected in entropy equilibrium with its surroundings.

•  More thermal pressure introduced.

•  Much greater field line distortion

•  Greater pressure, shock wave, bow-like structure

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Future work

Large scale evolution of jets

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t=100 t=120 t=140 t=160

Pressure

Eqm.

Entropy

Eqm.