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Related papers: Thermal conduction and reduced cooling flows in ga…

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Thermal conduction in tangled magnetic fields is reduced because heat conducting electrons must travel along the field lines longer distances between hot and cold regions of space than if there were no fields. We consider the case when the…

Astrophysics · Physics 2009-10-31 Leonid Malyshkin

This is the first part of a study of the detailed X-ray properties of the cores of nearby clusters. We have used the flux-limited sample of 55 clusters of Edge et al. (1990) and archival and proprietary data from the {\it ROSAT}…

Astrophysics · Physics 2009-10-30 C. B. Peres , A. C. Fabian , A. C. Edge , S. W. Allen , R. M. Johnstone , D. A. White

We use Chandra data to derive a detailed gas temperature map of the nearby, hot, merging galaxy cluster A754. Combined with the X-ray and optical images, the map reveals a more complex merger geometry than previously thought, possibly…

The cooling cores of clusters of galaxies are among the brightest thermal X-ray line sources in the universe. High resolution X-ray spectra would allow individual line fluxes to be measured. The fluxes of low ionization X-ray lines in…

Astrophysics · Physics 2007-05-23 Craig L. Sarazin

A new model for cooling flows in X-ray clusters, capable of naturally explaining salient features observed, is proposed. The only requirement is that a significant relativistic component, in the form of cosmic rays (CR), be present in the…

Astrophysics · Physics 2009-11-10 Renyue Cen

In this paper, we investigate the effect of cooling on the X-ray properties of galaxy clusters. We have performed N-body, hydrodynamical simulations both with and without the effects of radiative cooling, but neglecting the effects of star…

Astrophysics · Physics 2009-10-31 F. R. Pearce , P. A. Thomas , H. M. P. Couchman , A. C. Edge

We examine the role of thermal conduction and magnetic fields in cores of galaxy clusters through global simulations of the intracluster medium (ICM). In particular, we study the influence of thermal conduction, both isotropic and…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-29 Baban Wagh , Prateek Sharma , Michael McCourt

During solar flares plasma is typically heated to very high temperatures, and the resulting redistribution of energy via thermal conduction is a primary mechanism transporting energy throughout the flaring solar atmosphere. The thermal flux…

Solar and Stellar Astrophysics · Physics 2022-06-01 Joel C. Allred , Graham S. Kerr , A. Gordon Emslie

We explore the relationship between the metallicity of the intracluster gas in clusters of galaxies, determined by X-ray spectroscopy, and the presence of cooling flows. Using ASCA spectra and ROSAT images, we demonstrate a clear…

Astrophysics · Physics 2009-10-30 S. W. Allen , A. C. Fabian

We propose a scenario in which a large fraction, or even most, of the gas cooling to low temperatures of T<10^4 K in cooling flow clusters, directly gains energy from the central black hole. Most of the cool gas is accelerated to…

Astrophysics · Physics 2009-11-10 Noam Soker , Fabio Pizzolato

We have calculated the emergent X-ray properties for models of cluster cooling flows including the effects of accumulated cooled material. The opacity of this cooled gas can reduce the overall X-ray luminosity of the cooling flow, and…

Astrophysics · Physics 2007-05-23 Michael W. Wise , Craig L. Sarazin

In many clusters of galaxies, the cooling time at the core of the intracluster medium is much less than the age of the system, suggesting that the the gas should continually lose energy by radiation. Simple thermodynamic arguments then…

We study steady, homogeneous and subsonic cooling flows in poor clusters of galaxies in light of the recent proposal that radiative cooling of the intracluster gas can explain the observations of the `entropy floor' and other related X-ray…

Astrophysics · Physics 2009-11-07 Biman B. Nath

The X-ray emission in many clusters of galaxies shows a central peak in surface brightness coincident with a drop in temperature. These characterize a cooling flow. There is often a radio source also at the centre of such regions. Data from…

Astrophysics · Physics 2007-05-23 A. C. Fabian

(Abridged) Cold fronts in cluster cool cores should be erased on short timescales by thermal conduction, unless protected by magnetic fields that are "draped" parallel to the front surfaces, suppressing conduction perpendicular to the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 J. A. ZuHone , M. Markevitch , M. Ruszkowski , D. Lee

Strong evidence for cooling flows has been found in low resolution X-ray imaging and spectra of many clusters of galaxies. However high resolution X-ray spectra of several clusters from the Reflection Grating Spectrometer (RGS) on…

Astrophysics · Physics 2009-10-31 A. C. Fabian , R. F. Mushotzky , P. E. J. Nulsen , J. R. Peterson

In the cores of some galaxy clusters the hot intracluster plasma is dense enough that it should cool radiatively in the cluster's lifetime, leading to continuous "cooling flows" of gas sinking towards the cluster center, yet no such cooling…

The existence of cooling flows in the center of galaxy clusters has always been a puzzle, and in particular the fate of the cooling gas, since the presence of cold gas has never been proven directly. X-ray data from the satellites Chandra…

Astrophysics · Physics 2017-01-18 F. Combes , P. Salome

The radiative cooling time of the hot gas at the centres of cool cores in clusters of galaxies drops down to 10 million years and below. The observed mass cooling rate of such gas is very low, suggesting that AGN feedback is very tightly…

Astrophysics of Galaxies · Physics 2022-08-03 A. C. Fabian , G. J. Ferland , J. S. Sanders , B. R. McNamara , C. Pinto , S. A. Walker

In the centers of many galaxy clusters, the hot ($\sim$10$^7$ K) intracluster medium (ICM) can become dense enough that it should cool on short timescales. However, the low measured star formation rates in massive central galaxies and…