The impact of cooling flows on the TX-LBol relation for the most luminous clusters

Allen, S. W.; Fabian, A. C.

doi:10.1046/j.1365-8711.1998.01737.x

Cited by 220 publications

(264 citation statements)

References 14 publications

(26 reference statements)

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“…This relation has been shown by several independent analyses to have a slope, L X ∝ T α , with α 3 for T 2 keV (e.g., White et al 1997), with indications for a flattening to α 2.5 for the most massive systems (Allen and Fabian 1998). The scatter in this relation is largely contributed by the cool-core emission, so that it significantly decreases when excising the cores (Markevitch 1998) or removing cool-core systems (Arnaud and Evrard 1999).…”

Section: The Luminosity-temperature Relationmentioning

confidence: 71%

Thermodynamical Properties of the ICM from Hydrodynamical Simulations

et al. 2008

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Modern hydrodynamical simulations offer nowadays a powerful means to trace the evolution of the X-ray properties of the intra-cluster medium (ICM) during the cosmological history of the hierarchical build up of galaxy clusters. In this paper we review the current status of these simulations and how their predictions fare in reproducing the most recent X-ray observations of clusters. After briefly discussing the shortcomings of the self-similar model, based on assuming that gravity only drives the evolution of the ICM, we discuss how the processes of gas cooling and non-gravitational heating are expected to bring model predictions into better agreement with observational data. We then present results from the hydrodynamical simulations, performed by different groups, and how they compare with observational data. As terms of comparison, we use X-ray scaling relations between mass, luminosity, temperature and pressure, as well as the profiles of temperature and entropy. The results of this comparison can be summarised as follows: (a) which include gas cooling, star formation and supernova feedback, are generally successful in reproducing the X-ray properties of the ICM outside the core regions; (b) simulations generally fail in reproducing the observed "cool core" structure, in that they have serious difficulties in regulating overcooling, thereby producing steep negative central temperature profiles. This discrepancy calls for the need of introducing other physical processes, such as energy feedback from active galactic nuclei, which should compensate the radiative losses of the gas with high density, low entropy and short cooling time, which is observed to reside in the innermost regions of galaxy clusters.

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Section: The Luminosity-temperature Relationmentioning

confidence: 71%

Thermodynamical Properties of the ICM from Hydrodynamical Simulations

et al. 2008

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“…Comparing the most likely rest-frame X-ray luminosities and temperatures of these two sources with the well-established L X -kT relation for clusters and groups (e.g., Allen & Fabian 1998;Xue & Wu 2000), we find that the X-ray temperature of source 2 is consistent with its bolometric luminosity if the X-ray source lies at high redshift (i.e., z & 0.7), while the X-ray temperature of source 6 is clearly too high to be consistent with its bolometric X-ray luminosity (compare with Fig. 1 of Xue & Wu 2000).…”

Section: Basic Nature Of the Extended X-ray Sourcesmentioning

confidence: 87%

The Chandra Deep Field North Survey. IX. Extended X-Ray Sources

Bauer¹,

Alexander²,

Brandt³

et al. 2002

The Astronomical Journal

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The %1 Ms Chandra Deep Field North observation is used to study the extended X-ray sources in the region surrounding the Hubble Deep Field North (HDF-N), yielding the most sensitive probe of extended X-ray emission at cosmological distances to date. A total of six such sources are detected, the majority of which align with small numbers of optically bright galaxies. Their angular sizes, band ratios, and X-ray luminosities-assuming they lie at the same distances as the galaxies coincident with the X-ray emission-are generally consistent with the properties found for nearby groups of galaxies. One source is notably different and is likely to be a poor-to-moderate X-ray cluster at high redshift (i.e., z & 0.7). This source has a large angular extent, a double-peaked X-ray morphology, and an overdensity of unusual objects [very red objects, optically faint (I ! 24) radio and X-ray sources]. Another of the six sources is coincident with several z % 1.01 galaxies located within the HDF-N itself, including the FR I radio galaxy VLA J123644+621133, and is likely to be a group or poor cluster of galaxies at that redshift. We are also able to place strong constraints on the optically detected cluster of galaxies ClG 1236+6215 at z = 0.85 and the wide-angle-tailed radio galaxy VLA J123725+621128 at z $ 1-2; both sources are expected to have considerable associated diffuse X-ray emission, and yet they have rest-frame 0.5-2.0 keV X-ray luminosities of .3 Â 10 42 and .(3-15) Â 10 42 ergs s À1 , respectively. The environments of both sources are either likely to have a significant deficit of hot intracluster gas compared with local clusters of galaxies, or they are X-ray groups. We find the surface density of extended X-ray sources in this observation to be 167 þ97 À67 deg À2 at a limiting soft-band flux of %3 Â 10 À16 ergs cm À2 s À1 . No evolution in the X-ray luminosity function of clusters is needed to explain this value.

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“…One way to obtain a scaling law closer to the observational one is either to inject non-gravitational energy into the ICM before or during cluster formation, the so-called pre-heating (Ponman et al 1999;Bower et al 1997;Cavaliere et al 1997Cavaliere et al , 1999Tozzi & Norman 2001;Borgani et al 2001;Voit & Brian 2001) or to consider feedback processes that alter the gas characteristics during the evolution of the cluster's (Voit & Bryan 2001) cooling flows (Allen & Fabian 1998). A similar situation is valid for the M − T relationship, namely that the self-similarity in the M − T relation seems to break at a few keV (Nevalanien et al 2000;Xu et al 2001;Finoguenov et al 2001;Muanwong et al 2001;Bialek et al 2001).…”

Section: Theorymentioning

confidence: 99%