Statistical Properties of Radio Halos in Galaxy Clusters and Origin of Seed Electrons for Reacceleration

Abstract

One of the most promising mechanisms for producing radio halos (RHs) in galaxy clusters is the reacceleration of cosmic-ray electrons by turbulences. However, the origin of the seed electrons for the reacceleration is still poorly constrained. In the secondary scenario, most of the seed electrons are injected via collision of proton cosmic-rays, while non-thermal electrons are directly injected in the primary scenario. In this paper, we examine the two scenarios for the seed electrons with the observed statistical properties of RHs, combining two methods: following the temporal evolutions of the electron energy and radial distributions in a cluster, and the merger history of clusters. We find that the RH lifetime largely depends on the seed origin, as it could be longer than the cosmological timescale in the secondary scenario. We study the condition for the onset of RHs with the observed RH fraction and the RH lifetime we obtained, and find that long-lived RHs in the secondary scenario should be originated from major mergers with a mass ratio of $\xi \sim 0.1$, while the short lifetime in the primary scenario requires more frequent onsets by minor mergers with $\xi \sim 0.01$. Our simple model of the turbulence acceleration can reproduce the observed radio luminosity-mass relation. The RH luminosity functions we obtained suggest that the expected RH number count with the ASKAP survey will detect $\approx 10^3$ RHs in both the scenarios.

29 pages, 14 figures, 2 tables, submitted to ApJ

References in corpus (23)

• Diffuse Radio Emission from Galaxy Clusters
• Science with ASKAP - the Australian Square Kilometre Array Pathfinder
• Compressible Turbulence in Galaxy Clusters: Physics and Stochastic Particle Re-acceleration
• Parameterization of Gamma, e^+/- and Neutrino Spectra Produced by p-p Interaction in Astronomical Environment
• On the connection between giant radio halos and cluster mergers
• A low-frequency radio halo associated with a cluster of galaxies
• Searching for Cool Core Clusters at High redshift
• GMRT Radio Halo Survey in galaxy clusters at z = 0.2 -- 0.4 I.The REFLEX sub--sample
• Hydrodynamic Simulation of Non-thermal Pressure Profiles of Galaxy Clusters
• Simulating cosmic rays in clusters of galaxies - II. A unified scheme for radio halos and relics with predictions of the gamma-ray emission
• Cosmic rays and Radio Halos in galaxy clusters : new constraints from radio observations
• The answer is blowing in the wind: Simulating the interaction of jets with dynamic cluster atmospheres
• Turbulence and Vorticity in Galaxy Clusters Generated by Structure Formation
• Turbulence and Particle Acceleration in Giant Radio Haloes: the Origin of Seed Electrons
• New scaling relations in cluster radio halos and the re-acceleration model
• Relativistic protons in the Coma galaxy cluster: first gamma-ray constraints ever on turbulent reacceleration
• The Matryoshka Run (II): Time Dependent Turbulence Statistics, Stochastic Particle Acceleration and Microphysics Impact in a Massive Galaxy Cluster
• LOFAR discovery of an ultra-steep radio halo and giant head-tail radio galaxy in Abell 1132
• The Nascent Red Sequence at z~2
• Radio halos in a mass-selected sample of 75 galaxy clusters. II. Statistical analysis
• Fast magnetic field amplification in distant galaxyclusters
• Can giant radio halos probe the merging rate of galaxy clusters?
• Particle Energy Diffusion in Linear Magnetohydrodynamic Waves

Cited by in corpus (8)

• The Planck clusters in the LOFAR sky: IV: LoTSS-DR2: statistics of radio halos and re-acceleration models
• The Planck clusters in the LOFAR sky. III. LoTSS-DR2: Dynamic states and density fluctuations of the intracluster medium
• Surface brightness discontinuities in radio halos. Insights from the MeerKAT Galaxy Cluster Legacy Survey
• The prototypical major cluster merger Abell 754. I. Calibration of MeerKAT data and radio/X-ray spectral mapping of the cluster
• Probing particle acceleration in Abell 2256: from to 16 MHz to gamma rays
• Double radio relics and radio halo in the high redshift galaxy cluster El Gordo with the Upgraded GMRT
• High-energy neutrino constraints on cosmic-ray re-acceleration in radio halos of massive galaxy clusters
• Non-thermal emissions from a head-tail radio galaxy in 3D magnetohydrodynamic simulations