SIMBAD references

2007MNRAS.379..260M - Mon. Not. R. Astron. Soc., 379, 260-274 (2007/July-3)

The interplay between radio galaxies and cluster environment.


Abstract (from CDS):

By combining the REFLEX and NORAS cluster data sets with the NVSS radio catalogue, we obtain a sample of 145, z < 0.3, X-ray-selected clusters brighter than 3x10–12 erg/s/cm2 that show a central radio emission above 3 mJy. For virial masses Mvir≲ 1014.5M, 11 clusters out of 12 (corresponding to 92 per cent of the systems) are inhabited by a central radio source. This fraction decreases with higher masses as ∝ M–0.4vir. If this decrease is a selection effect, it suggests that the majority of X-ray-selected clusters host in their centre a radio source brighter than ∼1020 W/Hz/sr. A division of the sample into clusters harbouring either point-like or an extended radio-loud active galactic nucleus (AGN) reveals that the steepening of the LX-T relation for low-temperature clusters is strongly associated with the presence of central radio objects with extended jets and/or lobe structures. In the latter case, LXT4 while for point-like sources one recovers an approximately self-similar relation LXT2.3. Monte Carlo simulations show that the steepening of the LX-T relation is not caused by clusters being underluminous in the X-ray band, but rather by overheating, most likely caused by the interplay between the extended radio structures and the intracluster medium. In the case of low-mass systems, we also find a tight correlation between radio luminosity and cluster temperature. The effects of the central radio source on the thermal state of a cluster become less important with increasing cluster mass.

The presence of radio sources with extended structures (61, corresponding to ∼42 per cent of the sample) is enhanced in X-ray luminous clusters with respect to `field' radio-loud AGN. Furthermore, we find that the luminosity distribution of the cluster radio population differs from that of all radio sources, as there is a deficit of low-luminosity (LR≲ 1022 W/Hz/sr) objects, while the number of high-luminosity ones is boosted. The net effect on the radio luminosity function of radio galaxies associated with cluster centres is of a flattening at all luminosities LR≲ 1024 W/Hz/sr.

Abstract Copyright: 2007 The Authors. Journal compilation © 2007 RAS

Journal keyword(s): galaxies: active - galaxies: clusters: general - galaxies: statistics - cosmology: observations - radio continuum: galaxies - X-rays: galaxies: clusters

VizieR on-line data: <Available at CDS (J/MNRAS/379/260): table1.dat>

Simbad objects: 152

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