2006/09/30 by M. Roncarelli, S. Ettori, Klaus Dolag +5 · 105 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Star Formation Studies #Cluster (spacecraft) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Intracluster medium #Physics #Power law #RADIUS #Range (aeronautics) #Surface brightness #Virial theorem #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2006.11143.x
published in Monthly Notices of the Royal Astronomical Society 373(4), 1339-1350 (Oxford University Press) · 13 pages, 6 figures; added reference and other minor changes
openalex publication_date 2006/11/21 · arxiv created 2007/01/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Using a set of hydrodynamical simulations of nine galaxy clusters with masses in the range 1.5 × 1014 < Mvir < 3.4 × 1015 M⊙, we have studied the density, temperature and X-ray surface brightness profiles of the intracluster medium in the regions around the virial radius. We have analysed the profiles in the radial range well above the cluster core, the physics of which are still unclear and matter of tension between simulated and observed properties, and up to the virial radius and beyond, where present observations are unable to provide any constraints. We have modelled the radial profiles between 0.3R200 and 3R200 with power laws with one index, two indexes and a rolling index. The simulated temperature and [0.5–2] keV surface brightness profiles well reproduce the observed behaviours outside the core. The shape of all these profiles in the radial range considered depends mainly on the activity of the gravitational collapse, with no significant difference among models including extraphysics. The profiles steepen in the outskirts, with the slope of the power-law fit that changes from −2.5 to −3.4 in the gas density, from −0.5 to −1.8 in the gas temperature and from −3.5 to −5.0 in the X-ray soft surface brightness. We predict that the gas density, temperature and [0.5–2] keV surface brightness values at R200 are, on average, 0.05, 0.60, 0.008 times the measured values at 0.3R200. At 2R200, these values decrease by an order of magnitude in the gas density and surface brightness, by a factor of 2 in the temperature, putting stringent limits on the detectable properties of the intracluster-medium (ICM) in the virial regions.