The University of Southampton
University of Southampton Institutional Repository

Simple models of cooling flows

Simple models of cooling flows
Simple models of cooling flows
A semi-analytic model of cluster cooling flows is presented. The model assumes that episodic nuclear activity followed by radiative cooling without mass-dropout cycles the cluster gas between a relatively homogeneous, nearly isothermal post-outburst state and a cuspy configuration in which a cooling catastrophe initiates the next nuclear outburst. Fitting the model to Chandra data for the Hydra cluster, a lower limit of 284 Myr until the next outburst of Hydra A is derived. Density, temperature and emission-measure profiles at several times prior to the cooling catastrophe are presented. It proves possible to fit the mass M(?) with entropy index P?-? less than ? to a simple power-law form, which is almost invariant as the cluster cools. We show that radiative cooling automatically establishes this power-law form if the entropy index was constant throughout the cluster gas at some early epoch or after an active galactic nucleus (AGN) activity cycle. To high precision, the central value of ? decreases linearly with time. The fraction of clusters in a magnitude-limited sample that have gas cooler than T is calculated, and is shown to be small for T= 2 keV. Similarly, only 1 per cent of clusters in such a sample contain gas with Pp-? < 2 keV cm2. Entropy production in shocks is shown to be small. The entropy that is radiated from the cluster can be replaced if a few per cent of the cluster gas passes through bubbles heated during an outburst of the AGN.
1365-2966
837-845
Kaiser, Christian R.
28e00576-1e5b-47f1-b24c-fa10689717ab
Binney, James
e7976a32-6314-4c31-a5ac-cf3f51e4056e
Kaiser, Christian R.
28e00576-1e5b-47f1-b24c-fa10689717ab
Binney, James
e7976a32-6314-4c31-a5ac-cf3f51e4056e

Kaiser, Christian R. and Binney, James (2003) Simple models of cooling flows. Monthly Notices of the Royal Astronomical Society, 338 (4), 837-845. (doi:10.1046/j.1365-8711.2003.06131.x).

Record type: Article

Abstract

A semi-analytic model of cluster cooling flows is presented. The model assumes that episodic nuclear activity followed by radiative cooling without mass-dropout cycles the cluster gas between a relatively homogeneous, nearly isothermal post-outburst state and a cuspy configuration in which a cooling catastrophe initiates the next nuclear outburst. Fitting the model to Chandra data for the Hydra cluster, a lower limit of 284 Myr until the next outburst of Hydra A is derived. Density, temperature and emission-measure profiles at several times prior to the cooling catastrophe are presented. It proves possible to fit the mass M(?) with entropy index P?-? less than ? to a simple power-law form, which is almost invariant as the cluster cools. We show that radiative cooling automatically establishes this power-law form if the entropy index was constant throughout the cluster gas at some early epoch or after an active galactic nucleus (AGN) activity cycle. To high precision, the central value of ? decreases linearly with time. The fraction of clusters in a magnitude-limited sample that have gas cooler than T is calculated, and is shown to be small for T= 2 keV. Similarly, only 1 per cent of clusters in such a sample contain gas with Pp-? < 2 keV cm2. Entropy production in shocks is shown to be small. The entropy that is radiated from the cluster can be replaced if a few per cent of the cluster gas passes through bubbles heated during an outburst of the AGN.

This record has no associated files available for download.

More information

Published date: February 2003

Identifiers

Local EPrints ID: 14783
URI: http://eprints.soton.ac.uk/id/eprint/14783
ISSN: 1365-2966
PURE UUID: 23720bb4-084d-4e94-930d-e56ec515988a

Catalogue record

Date deposited: 28 Feb 2005
Last modified: 15 Mar 2024 05:31

Export record

Altmetrics

Contributors

Author: Christian R. Kaiser
Author: James Binney

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.

×