Relativistic 3D precessing jet simulations for the X-ray binary SS433

¹ Centre for mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, 3001 Heverlee, Belgium
e-mail: Remi.MonceauBaroux@wis.kuleuven.be
² LUTh, Observatoire de Paris, 75014 Paris, France
³ Department of Applied Mathematics, The University of Leeds, Leeds, LS2 9JT, UK

Received: 16 September 2013
Accepted: 10 November 2013

Abstract

Context. Modern high-resolution radio observations allow us a closer look into the objects that power relativistic jets. This is especially the case for SS433, an X-ray binary that emits a precessing jet that is observed down to the subparsec scale.

Aims. We aim to study full 3D dynamics of relativistic jets associated with active galactic nuclei or X-ray binaries (XRB). In particular, we incorporate the precessing motion of a jet into a model for the jet associated with the XRB SS433. Our study of the jet dynamics in this system focuses on the subparsec scales. We investigate the impact of jet precession and the variation of the Lorentz factor of the injected matter on the general 3D jet dynamics and its energy transfer to the surrounding medium. After visualizing and quantifying jet dynamics, we aim to realize synthetic radio mapping of the data, to compare our results with observations.

Methods. For our study we used a block-tree adaptive mesh refinement scheme and an inner time-dependent boundary prescription to inject precessing bipolar supersonic jets. Parameters extracted from observations were used. Different 3D jet realizations that match the kinetic flux of the SS433 jet were intercompared, which vary in density contrast and jet beam velocity. We tracked the energy content deposited in different regions of the domain affected by the jet. Our code allows us to follow the adiabatic cooling of a population of relativistic particles injected by the jet. This evolving energy spectrum of accelerated electrons, using a pressure-based proxy for the magnetic field, allowed us to obtain the radio emission from our simulation.

Results. We find a higher energy transfer for a precessing jet than for standing jets with otherwise identical parameters as a result of the effectively increased interaction area. We obtain synthetic radio maps for all jets, from which one can see that dynamical flow features are clearly linked with enhanced emission sites.

Conclusions. The synthetic radio map best matches a jet model with the canonical propagation speed of 0.26c and a precession angle of 20°. Overdense precessing jets experience significant deceleration in their propagation through the interstellar medium, while the overall jet is of helical shape. Our results show that the kinematic model for SS433 has to be corrected for deceleration assuming ballistic propagation on a subparsec scale.