Can giant radio halos probe the merging rate of galaxy clusters?

Abstract

Radio and X-ray observations of galaxy clusters probe a direct link between cluster mergers and giant radio halos (RH), suggesting that these sources can be used as probes of the cluster merging rate with cosmic time. In this paper we carry out an explorative study that combines the observed fractions of merging clusters (fm) and RH (fRH) with the merging rate predicted by cosmological simulations and attempt to infer constraints on merger properties of clusters that appear disturbed in X-rays and of clusters with RH. We use morphological parameters to identify merging systems and analyze the currently largest sample of clusters with radio and X-ray data (M500>6d14 Msun, and 0.2<z<0.33, from the Planck SZ cluster catalogue). We found that in this sample fm~62-67% while fRH~44-51%. The comparison of the theoretical f_m with the observed one allows to constrain the combination (xi_m,tau_m), where xi_m and tau_m are the minimum merger mass ratio and the timescale of merger-induced disturbance. Assuming tau_m~ 2-3 Gyr, as constrained by simulations, we find that the observed f_m matches the theoretical one for xi_m~0.1-0.18. This is consistent with optical and near-IR observations of clusters in the sample (xi_m~0.14-0.16). The fact that RH are found only in a fraction of merging clusters may suggest that merger events generating RH are characterized by larger mass ratio; this seems supported by optical/near-IR observations of RH clusters in the sample (xi_min~0.2-0.25). Alternatively, RH may be generated in all mergers but their lifetime is shorter than τ_m (by ~ fRH/fm). This is an explorative study, however it suggests that follow up studies using the forthcoming radio surveys and adequate numerical simulations have the potential to derive quantitative constraints on the link between cluster merging rate and RH at different cosmic epochs and for different cluster masses.

10 pages, 3 figures, accepted for publication in A&A

References in corpus (25)

• The Evolution of Galaxy Structure over Cosmic Time
• Compressible Turbulence in Galaxy Clusters: Physics and Stochastic Particle Re-acceleration
• On the connection between giant radio halos and cluster mergers
• The impact of mergers on relaxed X-ray clusters - I. Dynamical evolution and emergent transient structures
• A low-frequency radio halo associated with a cluster of galaxies
• The Nearly Universal Merger Rate of Dark Matter Haloes in Lambda-CDM Cosmology
• Galaxy growth in the concordance $\Lambda$CDM cosmology
• Searching for Cool Core Clusters at High redshift
• GMRT Radio Halo Survey in galaxy clusters at z = 0.2 -- 0.4. II.The eBCS clusters and analysis of the complete sample
• GMRT Radio Halo Survey in galaxy clusters at z = 0.2 -- 0.4 I.The REFLEX sub--sample
• Statistics of Giant Radio Halos from Electron Reacceleration Models
• A Dark Core in Abell 520
• Cosmic rays and Radio Halos in galaxy clusters : new constraints from radio observations
• Cosmology and Astrophysics from Relaxed Galaxy Clusters I: Sample Selection
• The Extended GMRT Radio Halo Survey II: Further results and analysis of the full sample
• The Matryoshka Run (II): Time Dependent Turbulence Statistics, Stochastic Particle Acceleration and Microphysics Impact in a Massive Galaxy Cluster
• An improved model for the formation times of dark matter haloes
• Internal dynamics of the radio-halo cluster A2744
• A Lensing Survey of X-ray Luminous Galaxy Clusters at Redshift z ~ 0.2: II: CFH12k Weak Lensing Analysis and Global Correlations
• Turbulent Velocity Fields in SPH--simulated Galaxy Clusters
• Morphology parameters: substructure identification in X-ray galaxy clusters
• Internal dynamics of the radio halo cluster Abell 773: a multiwavelength analysis
• How unusual is the cool-core radio halo cluster CL1821+643 ?
• Merger history trees of dark matter haloes in moving barrier models
• The structure of Abell 1351: a bimodal galaxy cluster with peculiar diffuse radio emission

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• Diffuse Radio Emission from Galaxy Clusters
• Relativistic protons in the Coma galaxy cluster: first gamma-ray constraints ever on turbulent reacceleration
• On the absence of radio halos in clusters with double relics
• Radio footprints of a minor merger in the Shapley Supercluster: From supercluster down to galactic scales
• New giant radio sources and underluminous radio halos in two galaxy clusters
• The Planck clusters in the LOFAR sky VI. LoTSS-DR2: Properties of radio relics
• Galaxy evolution in merging clusters: The passive core of the "Train Wreck" cluster of galaxies, A520
• Statistical Properties of Radio Halos in Galaxy Clusters and Origin of Seed Electrons for Reacceleration
• The merging galaxy cluster Abell 3266 at low radio frequencies
• Contribution of Radio Halos to the Foreground for SKA EoR Experiments
• A low-frequency radio halo survey of the South Pole Telescope SZ-selected clusters with the GMRT
• Jet interaction with galaxy cluster mergers
• Radio halos in a mass-selected sample of 75 galaxy clusters. I. Sample selection and data analysis
• Particle Reacceleration by Turbulence and Radio Constraints on Multi-Messenger High-Energy Emission from the Coma Cluster