Research Collaboration on Plasma Astrophysics between St John’s College Oxford and UCD

Researchers led by Dr Katherine Blundell and Professor James Binney FRS in Oxford and Dr Peter Duffy in Dublin, will work towards understanding the role played by magnetised turbulence in the transport and acceleration of highly energetic particles in quasars and microquasars.

The theoretical and computational models developed in UCD and Oxford will then be compared with the data gleaned from the astronomical observations. The result will be numerical codes and visualisation software to simulate transport in the turbulent magnetic fields along relativistic jets and the resulting radiative transfer.

“The dynamics of jet formation clearly involve both gravity and electromagnetism, but the similarities between jets in systems with radically different scales suggests that the underlying physics is simple”, said Dr Blundell. “It is nevertheless far from understood. We propose to advance our understanding of that physics by combining developments in plasma physics with state-of-the-art radio and X-ray observations of both microquasars and radio galaxies.”

A unique feature of this project will be its interdisciplinary nature; drawing on the fields of observational astronomy, theoretical physics, computational science and developments in transport theory for terrestrial, nuclear fusion plasmas.

The UCD team will concentrate on theoretical work on the microphysics scale, using a combination of analytical calculations and large-scale simulations to explore the mechanisms by which charged particles are accelerated and then transported within radio sources.

The Oxford team will concentrate on observations and modelling on the macro-scale. Firstly, reducing and interpreting the data obtained through an observational programme using cutting-edge facilities to observe key sources at a range of frequencies in radio and X-rays. Secondly, combining the observable consequences of the microphysics studied in Dublin with models of the gross structure of the observed sources to produce predictions for what should be actually observed, at both radio wavelengths and X-ray frequencies.

Radio and X-ray astronomy are key diagnostics in tracing energetic particles that are being transported by background magnetic fields in the regions, known as lobes, surrounding such galaxies. “It is imperative that we advance our understanding of the relevance and prevalence of transport mechanisms of charged particles responsible for the radiation within these jets and lobes, and not just within a very narrow regime in parameter space”, said Dr Duffy.

Dr Blundell, an expert in radio astronomy and plasma physics, published papers in 2000-2001 showing that a mechanism is needed to transport particles quickly in these lobes over vast distances in a turbulent magnetic field. Already familiar with Dr Duffy’s work at the Max Planck Institute for Nuclear Physics in the mid-nineties, addressing the transport of very fast particles in turbulent magnetic fields, Dr Blundell established contact with him in UCD and the collaboration began.

Realising that the research was also applicable to a second class of object known as microquasars – scaled down versions of quasars found within our own Milky Way Galaxy, Dr Duffy and Dr Blundell co-authored three papers in the Astrophysical Journal and Plasma Physics and Controlled Fusion. In 2003-2004 they realised that a determined effort to solve these problems would require a large, inter-disciplinary team of researchers.