A Semi-Analytical Model for the Formation and Evolution of Radio Relics in Galaxy Clusters

Abstract

Radio relics are Mpc-sized synchrotron sources located in the peripheral regions of galaxy clusters. Models based on the diffuse shock acceleration (DSA) scenario have been widely accepted to explain the formation of radio relics. However, a critical challenge to these models is that most observed shocks seem too weak to generate detectable emission, unless fossil electrons, a population of mildly energetic electrons that have been accelerated previously, are included in the models. To address this issue, we present a new semi-analytical model to describe the formation and evolution of radio relics by incorporating fossil relativistic electrons into DSA theory, which is constrained by a sample of 14 observed relics, and employ the Press-Schechter formalism to simulate the relics in a $20^{\circ }\times 20^{\circ }$ sky field at 50, 158, and 1400 MHz, respectively. Results show that fossil electrons contribute significantly to the radio emission, which can generate radiation four orders of magnitude brighter than that solely produced by thermal electrons at 158 MHz, and the power distribution of our simulated radio relic catalog can reconcile the observed $P_{1400}-M_{\mathrm{vir}}$ relation. We predict that $7.1\%$ clusters with $M_{\mathrm{vir}}>1.2\times 10^{14}{\mathrm{M}}_{\odot }$ would host relics at 158 MHz, which is consistent with the result of $10\pm 6\%$ given by the LoTSS DR2. It is also found that radio relics are expected to cause severe foreground contamination in future EoR experiments, similar to that of radio halos. The possibility of AGN providing seed fossil relativistic electrons is evaluated by calculating the number of radio-loud AGNs that a shock is expected to encounter during its propagation.

15 pages, 20 figures. Accepted for publication in MNRAS. Comments welcome

References in corpus (25)

• Diffuse Radio Emission from Galaxy Clusters
• Revised equipartition & minimum energy formula for magnetic field strength estimates from radio synchrotron observations
• Foreground simulations for the LOFAR - Epoch of Reionization Experiment
• Radio signature of cosmological structure formation shocks
• The Case for Electron Re-Acceleration at Galaxy Cluster Shocks
• A new double radio relic in PSZ1 G096.89+24.17 and a radio relic mass-luminosity relation
• Deep VLA observations of the cluster 1RXS J0603.3+4214 in the frequency range 1-2 GHz
• The Planck clusters in the LOFAR sky. I. LoTSS-DR2: new detections and sample overview
• Deep radio observations of the radio halo of the bullet cluster 1E 0657-55.8
• De-contamination of cosmological 21-cm maps
• The beautiful mess in Abell 2255
• Deep LOFAR observations of the merging galaxy cluster CIZA J2242.8+5301
• MC^2: Constraining the Dark Matter Distribution of the Violent Merging Galaxy Cluster CIZA J2242.8+5301 by Piercing through the Milky Way
• VLA Radio Observations of the HST Frontier Fields Cluster Abell 2744: The Discovery of New Radio Relics
• Electron Preacceleration in Weak Quasi-perpendicular Shocks in High-beta Intracluster Medium
• Exploring the spectral properties of radio relics I: Integrated spectral index and Mach number
• The first Murchison Widefield Array low frequency radio observations of cluster scale non-thermal emission: the case of Abell 3667
• How merger-driven gas motions in galaxy clusters can turn AGN bubbles into radio relics
• Observations of a Pre-Merger Shock in Colliding Clusters of Galaxies
• Analytical model for cluster radio relics
• A 3.5 Mpc-long radio relic in the galaxy cluster ClG 0217+70
• The extended ROSAT-ESO Flux-Limited X-ray Galaxy Cluster Survey (REFLEX II) VII The Mass Function of Galaxy Clusters
• A study of halo and relic radio emission in merging clusters using the Murchison Widefield Array
• Contribution of Radio Halos to the Foreground for SKA EoR Experiments
• The Merger Dynamics of the Galaxy Cluster Abell 1775: New Insights from Chandra and XMM-Newton for a Cluster Simultaneously Hosting a WAT and a NAT Radio Sources

Cited by in corpus (1)

• The prototypical major cluster merger Abell 754. I. Calibration of MeerKAT data and radio/X-ray spectral mapping of the cluster