Pulsars, transients and relativistic astrophysics

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Nonthermal emission in radio galaxies from simulated relativistic electron transport in 3D MHD flows

ASTR SOC P 250 (2002) 336-339

Authors:

IL Tregillis, TW Jones, D Ryu

Abstract:

We perform a series of so-called "synthetic observations" on a set of 3D MHD jet simulations which explicitly include energy-dependent transport of relativistic electrons, as described in the companion paper by Jones, Tregillis & Ryu. Analyzing them in light of the complex source dynamics and energetic particle distributions described in that paper, we find that the standard model for radiative aging in radio galaxies does not always adequately reflect the detailed source structure.
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Numerical simulation of test particle diffusive shock acceleration in relativistic shocks with application to AGN 'central engines'

ASTR SOC P 250 (2002) 48-52

Authors:

JJ Quenby, A Meli

Abstract:

Numerical modelling is performed for extreme relativistic parallel shocks with upstream Lorentz factors Gamma = 50. Assuming that the scattering is either large-angle or over pitch angles > Gamma(-1), spectral flattening and shock acceleration speed-up is found. The energy gain per cycle is similar to Gamma(2). The likely output from relativistic shocks due to the infall from the accretion disc to the AGN black hole is computed. Neutrinos from proton-gamma interactions may be detectable with planned neutrino telescopes but the gamma-ray output may contribute only 1/100th of the observed flux of 3C 273.
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Observations of the Sunyaev-Zel'dovich effect in the z=0.78 cluster MS 1137.5+6625

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 334:2 (2002) 323-326

Authors:

G Cotter, HJ Buttery, R Das, ME Jones, K Grainge, GG Pooley, R Saunders
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On the nature of angular momentum transport in nonradiative accretion flows

ASTROPHYSICAL JOURNAL 573:2 (2002) 749-753

Authors:

SA Balbus, JF Hawley
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On the origin of the Fanaroff-Riley dichotomy

ASTR SOC P 250 (2002) 290-293

Authors:

Gopal-Krishna, PJ Wiita

Abstract:

A small fraction of double radio sources show a peculiar and striking hybrid morphology; they have a distinctly FRI structure on one side of the nucleus, and a FRII structure on the other. We argue that the mere existence of these HYMORS is quite incompatible with the theoretical explanations for the Fanaxoff-Riley dichotomy that are based upon the nature of the jet plasma, or those invoking an intrinsic property of the central engine. Rather, these HYMORS strongly support models that explain the difference between FRI and FRII sources in terms of asymmetry of interaction of the jets with the external environments. We further show that a model for radio source dynamics we had earlier proposed can neatly reproduce the observed dependence of the radio power dividing the two FR classes on the optical luminosity of the host galaxy, as found by Owen & White and Ledlow Owen.
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