Modelling injection and feedback of cosmic rays in grid-based cosmological simulations: effects on cluster outskirts

Vazza, Franco; Brüggen, M.; Gheller, C.; Brunetti, G.

doi:10.1111/j.1365-2966.2012.20562.x

Cited by 56 publications

(75 citation statements)

References 102 publications

(230 reference statements)

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“…Disc-shaped shock fronts with a cylindrical wake can be seen in hydrodynamical simulations of cluster mergers (e.g. Vazza et al 2012) and provide a simple yet realistic model for deprojecting the Planck y-map.…”

Section: Discussionmentioning

confidence: 99%

Evidence for a pressure discontinuity at the position of the Coma relic from Planck Sunyaev–Zel'dovich effect data

Erler

Basu

Trasatti

et al. 2015

Monthly Notices of the Royal Astronomical Society

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Radio relics are Mpc-scale diffuse synchrotron sources found in galaxy cluster outskirts. They are believed to be associated with large-scale shocks propagating through the intracluster medium, although the connection between radio relics and the cluster merger shocks is not yet proven conclusively. We present a first tentative detection of a pressure jump in the well-known relic of the Coma cluster through Sunyaev-Zel'dovich (SZ) effect imaging. The SZE data are extracted from the first public all-sky data release of Planck and we use highfrequency radio data at 2.3 GHz to constrain the shock-front geometry. The SZE data provide evidence for a pressure discontinuity, consistent with the relic position, without requiring any additional prior on the shock-front location. The derived Mach number M = 2.9 +0.8 −0.6 is consistent with X-ray and radio results. A high-pressure "filament" without any pressure discontinuity is disfavoured by X-ray measurements and a "sub-cluster" model based on the infalling group NGC 4839 can be ruled out considering the published mass estimates for this group. These results signify a first attempt towards directly measuring the pressure discontinuity for a radio relic and the first SZ-detected shock feature observed near the virial radius of a galaxy cluster.

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Section: Discussionmentioning

confidence: 99%

Evidence for a pressure discontinuity at the position of the Coma relic from Planck Sunyaev–Zel'dovich effect data

Erler

Basu

Trasatti

et al. 2015

Monthly Notices of the Royal Astronomical Society

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“…The generation can be taken into account in the CR MHD equations, if it is modelled successfully (see e.g. Zank et al 1993;Jubelgas et al 2008;Vazza et al 2012). Thus far, only the energy injection rate, is taken into account in the literature.…”

Section: Discussionmentioning

confidence: 99%

“…Bykov 2014), and cosmological structure formation through shocks (see e.g. Pfrommer et al 2006;Vazza et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Approximate Riemann solvers for the cosmic ray magnetohydrodynamical equations

Kudoh

Hanawa

2016

Mon. Not. R. Astron. Soc.

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We analyze the cosmic-ray magnetohydrodynamic (CR MHD) equations to improve the numerical simulations. We propose to solve them in the fully conservation form, which is equivalent to the conventional CR MHD equations. In the fully conservation form, the CR energy equation is replaced with the CR "number" conservation, where the CR number density is defined as the three fourths power of the CR energy density. The former contains an extra source term, while latter does not. An approximate Riemann solver is derived from the CR MHD equations in the fully conservation form. Based on the analysis, we propose a numerical scheme of which solutions satisfy the Rankine-Hugoniot relation at any shock. We demonstrate that it reproduces the Riemann solution derived by Pfrommer et al. (2006) for a 1D CR hydrodynamic shock tube problem. We compare the solution with those obtained by solving the CR energy equation. The latter solutions deviate from the Riemann solution seriously, when the CR pressure dominates over the gas pressure in the post-shocked gas. The former solutions converge to the Riemann solution and are of the second order accuracy in space and time. Our numerical examples include an expansion of high pressure sphere in an magnetized medium. Fast and slow shocks are sharply resolved in the example. We also discuss possible extension of the CR MHD equations to evaluate the average CR energy.

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“…Pfrommer et al (2007) and Vazza et al (2012), adopting specific DSA efficiency models, showed that the CR acceleration occurs mostly in the cluster outskirts. Because of long lifetime and slow particle diffusion (e.g., Berezinsky et al 1997), the CR protons accelerated in the outskirts are likely to be contained in clusters and accumulated in the ICM over cosmological timescales.…”

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confidence: 99%

“…In some simulations for the LSS formation, the injection/ acceleration of CR protons at shocks and the spatial advection of the CR pressure were followed self-consistently in runtime (e.g., Miniati et al 2001;Pfrommer et al 2007;Vazza et al 2012). Pfrommer et al (2007) and Vazza et al (2012), adopting specific DSA efficiency models, showed that the CR acceleration occurs mostly in the cluster outskirts.…”

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confidence: 99%

Shock Waves and Cosmic Ray Acceleration in the Outskirts of Galaxy Clusters

Hong

Ryu

Kang

et al. 2014

ApJ

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The outskirts of galaxy clusters are continuously disturbed by mergers and gas infall along filaments, which in turn induce turbulent flow motions and shock waves. We examine the properties of shocks that form within r 200 in sample galaxy clusters from structure formation simulations. While most of these shocks are weak and inefficient accelerators of cosmic rays (CRs), there are a number of strong, energetic shocks which can produce large amounts of CR protons via diffusive shock acceleration. We show that the energetic shocks reside mostly in the outskirts and a substantial fraction of them are induced by infall of the warm-hot intergalactic medium from filaments. As a result, the radial profile of the CR pressure in the intracluster medium is expected to be broad, dropping off more slowly than that of the gas pressure, and might be even temporarily inverted, peaking in the outskirts. The volume-integrated momentum spectrum of CR protons inside r 200 has the power-law slope of 4.25-4.5, indicating that the average Mach number of the shocks of main CR production is in the range of M s CR ≈ 3-4. We suggest that some radio relics with relatively flat radio spectrum could be explained by primary electrons accelerated by energetic infall shocks with M s 3 induced in the cluster outskirts.

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Modelling injection and feedback of cosmic rays in grid-based cosmological simulations: effects on cluster outskirts

Cited by 56 publications

References 102 publications

Evidence for a pressure discontinuity at the position of the Coma relic from Planck Sunyaev–Zel'dovich effect data

Evidence for a pressure discontinuity at the position of the Coma relic from Planck Sunyaev–Zel'dovich effect data

Approximate Riemann solvers for the cosmic ray magnetohydrodynamical equations

Shock Waves and Cosmic Ray Acceleration in the Outskirts of Galaxy Clusters

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