Exploring the role of cosmological shock waves in the Dianoga simulations of galaxy clusters

Abstract

Cosmological shock waves are ubiquitous to cosmic structure formation and evolution. As a consequence, they play a major role in the energy distribution and thermalization of the intergalactic medium (IGM). We analyze the Mach number distribution in the Dianoga simulations of galaxy clusters performed with the SPH code GADGET-3. The simulations include the effects of radiative cooling, star formation, metal enrichment, supernova and active galactic nuclei feedback. A grid-based shock-finding algorithm is applied in post-processing to the outputs of the simulations. This procedure allows us to explore in detail the distribution of shocked cells and their strengths as a function of cluster mass, redshift and baryonic physics. We also pay special attention to the connection between shock waves and the cool-core/non-cool core (CC/NCC) state and the global dynamical status of the simulated clusters. In terms of general shock statistics, we obtain a broad agreement with previous works, with weak (low-Mach number) shocks filling most of the volume and processing most of the total thermal energy flux. As a function of cluster mass, we find that massive clusters seem more efficient in thermalising the IGM and tend to show larger external accretion shocks than less massive systems. We do not find any relevant difference between CC and NCC clusters. However, we find a mild dependence of the radial distribution of the shock Mach number on the cluster dynamical state, with disturbed systems showing stronger shocks than regular ones throughout the cluster volume.

Shocks in the Stacked Sunyaev-Zel'dovich Profiles of Clusters II: Measurements from SPT-SZ + Planck Compton-y Map

“…As was noted before, the current astrophysical picture of shocks has been studied predominantly using hydrodynamical simulations (Quilis et al 1998;Miniati et al 2000;Ryu et al 2003;Pfrommer et al 2006Pfrommer et al , 2007Kang et al 2007;Skillman et al 2008;Vazza et al 2009;Molnar et al 2009;Planelles & Quilis 2013;Vazza et al 2013Vazza et al , 2014Hong et al 2014Hong et al , 2015Lau et al 2015;Schaal & Springel 2015;Schaal et al 2016;Nelson et al 2016;Ha et al 2018;Zhang et al 2019Zhang et al , 2020Aung et al 2020;Baxter et al 2021;Zhang et al 2021;Planelles et al 2021), with the combined set of works using a wide variety of hydrodynamical solvers and astrophysical model prescriptions; see Vazza et al (2011) and Power et al (2020) for comparison studies of different implementations. These works are accompanied by observational studies of shocks that have focused predominantly on small samples -often containing just one object -of local, low-redshift clusters (Akamatsu et al 2011;Akahori & Yoshikawa 2012;Akamatsu et al 2016;Basu et al 2016;Di Mascolo et al 2019a,b;Hurier et al 2019;Pratt et al 2021;Zhu et al 2021).…”

Shocks in the stacked Sunyaev-Zel’dovich profiles of clusters II: Measurements from SPT-SZ + Planck Compton-y map

“…Initial studies used non-radiative simulations that modelled gas dynamics but did not include any non-gravitational processes such as gas cooling (Quilis et al 1998;Miniati et al 2000;Ryu et al 2003;Skillman et al 2008;Molnar et al 2009;Hong et al 2014Hong et al , 2015Schaal & Springel 2015). More recent studies have included the effects of gas cooling and star formation (Vazza et al 2009;Planelles & Quilis 2013;Lau et al 2015;Nelson et al 2016;Aung et al 2020), and as well as the effects of feedback from supernovae and active galactic nuclei (Kang et al 2007;Vazza et al 2013Vazza et al , 2014Schaal et al 2016;Baxter et al 2021;Planelles et al 2021). Some work has self-consistently modelled the evolution of cosmic-rays alongside galaxy formation (Pfrommer et al 2007), while a handful have also used idealized simulations to explore the propogation of shocks and their dependence on merger events (Pfrommer et al 2006;Ha et al 2018;Zhang et al 2019Zhang et al , 2020Zhang et al , 2021.…”