SIMBAD references

2006MNRAS.367.1121P - Mon. Not. R. Astron. Soc., 367, 1121-1131 (2006/April-2)

Heating rate profiles in galaxy clusters.


Abstract (from CDS):

In recent years, evidence has accumulated suggesting that the gas in galaxy clusters is heated by non-gravitational processes. Here, we calculate the heating rates required to maintain a physically motivated mass flow rate, in a sample of seven galaxy clusters. We employ the spectroscopic mass deposition rates as an observational input along with temperature and density data for each cluster. On energetic grounds, we find that thermal conduction could provide the necessary heating for A2199, Perseus, A1795 and A478. However, the suppression factor of the classical Spitzer value is a different function of radius for each cluster. Based on the observations of plasma bubbles, we also calculate the duty cycles for each active galactic nucleus (AGN), in the absence of thermal conduction, which can provide the required energy input. With the exception of Hydra-A, it appears that each of the other AGNs in our sample requires duty cycles of roughly 106-107 yr to provide their steady-state heating requirements. If these duty cycles are unrealistic, this may imply that many galaxy clusters must be heated by very powerful Hydra-A type events interspersed between more frequent smaller scale outbursts. The suppression factors for the thermal conductivity required for combined heating by AGN and thermal conduction are generally acceptable. However, these suppression factors still require `fine-tuning' of the thermal conductivity as a function of radius. As a consequence of this work, we present the AGN duty cycle as a cooling flow diagnostic.

Abstract Copyright: 2006 The Authors. Journal compilation © 2006 RAS

Journal keyword(s): hydrodynamics - galaxies: active - galaxies: clusters: general - cooling flows

Status at CDS:  

Simbad objects: 9

goto Full paper

goto View the reference in ADS

To bookmark this query, right click on this link: simbad:2006MNRAS.367.1121P and select 'bookmark this link' or equivalent in the popup menu


© Université de Strasbourg/CNRS

    • Contact