Cosmic-Ray Protons Accelerated at Cosmological Shocks and Their Impact on Groups and Clusters of Galaxies

By Francesco Miniati, D. Ryu, Hyesung Kang, T. Jones. 2001

135 citations recorded by the source corpus.

We investigate the production of cosmic-ray (CR) protons at cosmological shocks by performing, for the first time, numerical simulations of large-scale structure formation that include directly the acceleration, transport, and energy losses of the high-energy particles. CRs are injected at shocks according to the thermal leakage model and, thereafter, accelerated to a power-law distribution as indicated by the test particle limit of the diffusive shock acceleration theory. The evolution of the CR protons accounts for losses owing to adiabatic expansion/compression, Coulomb collisions, and inelastic p-p scattering. Our results suggest that CR protons produced at shocks formed in association with the process of large-scale structure formation could amount to a substantial fraction of the total pressure in the intracluster medium. Their presence should be easily revealed by GLAST (Gamma-Ray Large-Area Space Telescope) through detection of γ-ray flux from the decay of π0 produced in inelastic p-p collisions of such CR protons with nuclei of the intracluster gas. This measurement will allow a direct determination of the CR pressure contribution in the intracluster medium. We also find that the spatial distribution of CR is typically more irregular than that of the thermal gas because it is more influenced by the underlying distribution of shocks. This feature is reflected in the appearance of our γ-ray synthetic images. Finally, the average CR pressure distribution appears statistically slightly more extended than the thermal pressure.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/9d3f1c2fde2ad72933001cb0deaf7c52e979e0af

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Citations in the corpus

Cosmic ray transport in galaxy clusters: implications for radio halos, gamma-ray signatures, and cool core heating (2010, background): “About two thirds of the most X-ray luminous clusters do not exhibit radio halos, whereas the hadronic model seems to suggests that all clusters exhibit halos (Miniati et al. 2001a; Miniati 2003; Pfrommer 2008; Pinzke & Pfrommer 2010).”
SEARCH FOR COSMIC-RAY-INDUCED GAMMA-RAY EMISSION IN GALAXY CLUSTERS (2013, background): “…only a modest CR-to-thermal pressure ratio of (at most) a few percent (Dennison 1980; Vestrand 1982; Blasi & Colafrancesco 1999; Dolag & Enßlin 2000; Miniati et al. 2001a,b; Miniati 2003; Pfrommer & Enßlin 2003, 2004a,b; Blasi et al. 2007; Pfrommer et al. 2008; Pfrommer 2008; Kushnir et al. 2009;…”
Cosmological Shocks in Adaptive Mesh Refinement Simulations and the Acceleration of Cosmic Rays (2008, background): “Cosmic rays from these low Mach number shocks will, however, have a steep energy spectrum and dissipate their energy relatively quickly compared to strong accretion shocks (e.g. Miniati et al. 2001).”
Cosmic ray feedback in hydrodynamical simulations of galaxy formation (2006, background): “In particular, it would be highly interesting to examine the effects of CRs on the metal distribution of the universe, or on the dynamics of buoyant bubbles inflated by AGN in clusters of galaxies.”
Cosmological Shock Waves and Their Role in the Large-Scale Structure of the Universe (2003, background): “Short electron lifetimes, however, lead that population to depend on other factors (Miniati et al. 2001a).”
Diffuse Radio Emission from Galaxy Clusters (2019, background): “Owing to their high-Mach numbers (M & 10), WHIM accretion shocks should accelerate particles (Miniati et al. 2001b; Ryu et al. 2003; Keshet et al. 2003), similar to what happens in clusters.”
Simulating cosmic rays in clusters of galaxies – II. A unified scheme for radio haloes and relics with predictions of the γ-ray emission (2007, methodology): “There have been pioneering efforts to simulate the non-thermal emission from clusters by numerically modelling discretised cosmic ray (CR) energy spectra on top of Eulerian grid-based cosmological simulations (Miniati 2001; Miniati et al. 2001a,b; Miniati 2002, 2003).”
Constraining the population of cosmic ray protons in cooling flow clusters with γ-ray and radio observations: Are radio mini-halos of hadronic origin? (2003, background): “An increase ofXCRp(r) towards the cluster’s periphery is indeed observed in cosmological structure formation simulations due to adiabatic compression inside the cluster which increases the thermal pressure at a higher rate than the CRp pressure (Miniati et al. 2001a,b).”
Cosmic-Ray Electrons in Groups and Clusters of Galaxies: Primary and Secondary Populations from a Numerical Cosmological Simulation (2001, methodology): “This component(Vo lk was not included in our simulation (Miniati et al. 2001) and should not be relevant for the secondary electrons in the energy range investigated here (e.g., Mannheim & Schlickeiser 1994).”