The University of Southampton
University of Southampton Institutional Repository

Heating of the intergalactic medium by FR II radio sources

Heating of the intergalactic medium by FR II radio sources
Heating of the intergalactic medium by FR II radio sources
We present results of a numerical integration of the hydrodynamical equations governing the self-similar, two-dimensional gas flow behind the bow shock of an FR II radio source embedded in an intergalactic medium (IGM) with a power-law density profile. The model predicts pressure gradients within the cocoons consistent with modest backflow. For very steep external density profiles, sources may well not expand in a self-similar fashion, and in this case the model is not self-consistent. The assumption of ram pressure confinement of the cocoons perpendicular to the jet axis is found to overestimate the ratio of the pressure in front of the radio hotspots and that in the cocoons. Based on the properties of the gas between bow shock and cocoon, we calculate the X-ray surface brightness of the flow. This emission is found to be a good tracer of the density distribution within the flow, and it varies significantly with the properties of the unshocked IGM. The cooling time of the shocked IGM is found to be comparable to, or greater than, the Hubble time. The influence of a radio source on the evolution of its gaseous surroundings therefore extends well beyond the limited lifetime of the source itself. We compare our results with the X-ray map of Cygnus A, and find some evidence for cold, dense gas clumps in the surroundings of this object. The extended X-ray emission observed around 3C 356 may also be caused by the bow shock of this radio source. We also present an empirical model for the X-ray emission of the shocked IGM resulting from thermal bremsstrahlung.
hydrodynamics, galaxies: active, galaxies: individual: Cygnus A, galaxies: individual: 3C 356, galaxies: jets, X-rays: galaxies
0035-8711
707-723
Kaiser, Christian R.
28e00576-1e5b-47f1-b24c-fa10689717ab
Alexander, Paul
fa89a721-0125-49a3-a4f4-1b5d848b8126
Kaiser, Christian R.
28e00576-1e5b-47f1-b24c-fa10689717ab
Alexander, Paul
fa89a721-0125-49a3-a4f4-1b5d848b8126

Kaiser, Christian R. and Alexander, Paul (1999) Heating of the intergalactic medium by FR II radio sources. Monthly Notices of the Royal Astronomical Society, 305 (3), 707-723.

Record type: Article

Abstract

We present results of a numerical integration of the hydrodynamical equations governing the self-similar, two-dimensional gas flow behind the bow shock of an FR II radio source embedded in an intergalactic medium (IGM) with a power-law density profile. The model predicts pressure gradients within the cocoons consistent with modest backflow. For very steep external density profiles, sources may well not expand in a self-similar fashion, and in this case the model is not self-consistent. The assumption of ram pressure confinement of the cocoons perpendicular to the jet axis is found to overestimate the ratio of the pressure in front of the radio hotspots and that in the cocoons. Based on the properties of the gas between bow shock and cocoon, we calculate the X-ray surface brightness of the flow. This emission is found to be a good tracer of the density distribution within the flow, and it varies significantly with the properties of the unshocked IGM. The cooling time of the shocked IGM is found to be comparable to, or greater than, the Hubble time. The influence of a radio source on the evolution of its gaseous surroundings therefore extends well beyond the limited lifetime of the source itself. We compare our results with the X-ray map of Cygnus A, and find some evidence for cold, dense gas clumps in the surroundings of this object. The extended X-ray emission observed around 3C 356 may also be caused by the bow shock of this radio source. We also present an empirical model for the X-ray emission of the shocked IGM resulting from thermal bremsstrahlung.

Full text not available from this repository.

More information

Published date: 1999
Keywords: hydrodynamics, galaxies: active, galaxies: individual: Cygnus A, galaxies: individual: 3C 356, galaxies: jets, X-rays: galaxies

Identifiers

Local EPrints ID: 14768
URI: http://eprints.soton.ac.uk/id/eprint/14768
ISSN: 0035-8711
PURE UUID: 666d0f74-aec1-4385-9578-f08ce19bdb59

Catalogue record

Date deposited: 28 Feb 2005
Last modified: 15 Jul 2019 19:33

Export record

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×