The correlation between radio power and Mach number for radio relics in galaxy clusters

Abstract

We discuss a new technique to constrain models for the origin of radio relics in galaxy clusters using the correlation between the shock Mach number and the radio power of relics. This analysis is carried out using a sample of relics with information on both the Mach numbers derived from X-ray observation, ${\mathcal{M}}_X$, and using spectral information from radio observations of the peak and the average values of the spectral index along the relic, ${\mathcal{M}}_R$. We find that there is a lack of correlation between ${\mathcal{M}}_X$ and ${\mathcal{M}}_R$; this result is an indication that the spectral index of the relic is likely not due to the acceleration of particles operated by the shock but it is related to the properties of a fossil electrons population. We also find that the available data on the correlation between the radio power $P_{1.4}$ and Mach numbers (${\mathcal{M}}_R$ and ${\mathcal{M}}_X$) in relics indicate that neither the DSA nor the adiabatic compression can simply reproduce the observed $P_{1.4}-\mathcal{M}$ correlations. Furthermore, we find that the radio power is not correlated with ${\mathcal{M}}_X$, whereas it is not possible to exclude a correlation with ${\mathcal{M}}_R$. This also indicates that the relic power is mainly determined by the properties of a fossil electron population rather than by the properties of the shock. Our results require either to consider models of shock (re)acceleration that go beyond the proposed scenarios of DSA and adiabatic compression at shocks, or to reconsider the origin of radio relics in terms of other physical scenarios.

arXiv comment14 pages, 8 figures. MNRAS, in press

References in corpus (73)

• Shocks and cold fronts in galaxy clusters
• Clusters of galaxies : observational properties of the diffuse radio emission
• Cosmological Shock Waves and Their Role in the Large Scale Structure of the Universe
• Radio sources in the 6dFGS: Local luminosity functions at 1.4 GHz for star-forming galaxies and radio-loud AGN
• Observations of extended radio emission in clusters
• The Energy Spectrum of Primary Cosmic Ray Electrons in Clusters of Galaxies and Inverse Compton Emission
• Radio Halo and Relic Candidates from the NRAO VLA Sky Survey
• Reviving Fossil Radio Plasma in Clusters of Galaxies by Adiabatic Compression in Environmental Shock Waves
• A Comparison of Radio and X-Ray Morphologies of Four Clusters of Galaxies Containing Radio Halos
• Radio and X-ray diffuse emission in six clusters of galaxies
• Radio signature of cosmological structure formation shocks
• The Case for Electron Re-Acceleration at Galaxy Cluster Shocks
• Diffusive Shock Acceleration Simulations of Radio Relics
• Diffuse Radio Emission in/around the Coma Cluster: Beyond Simple Accretion
• Giant radio relics in galaxy clusters: reacceleration of fossil relativistic electrons?
• Gas Clumping in the Outskirts of Lambda-CDM Clusters
• Non-Thermal Electron Acceleration in Low Mach Number Collisionless Shocks. I. Particle Energy Spectra and Acceleration Mechanism
• Evidence for particle re-acceleration in the radio relic in the galaxy cluster PLCKG287.0 +32.9
• Shock acceleration as origin of the radio relic in A521?
• A2255: the First Detection of Filamentary Polarized Emission in a Radio Halo
• Deep 1.4 GHz VLA Observations of the Radio Halo and Relic in Abell 2256
• The "toothbrush-relic": evidence for a coherent linear 2-Mpc scale shock wave in a massive merging galaxy cluster?
• Systematic X-ray Analysis of Radio Relic Clusters with SUZAKU
• A shock front in the merging galaxy cluster Abell 754: X-ray and radio observations
• Double relics in Abell 2345 and Abell 1240: spectral index and polarization analysis
• Cosmological MHD Simulations of Galaxy Cluster Radio Relics: Insights and Warnings for Observations
• Another shock for the Bullet cluster, and the source of seed electrons for radio relics
• Re-acceleration of Nonthermal Particles at Weak Cosmological Shock Waves
• Revealing the magnetic field in a distant galaxy cluster: discovery of the complex radio emission from MACS J0717.5 +3745
• Radio continuum observations of new radio halos and relics from the NVSS and WENSS surveys
• Shock heating of the merging galaxy cluster A521
• Challenges to our understanding of radio relics: X-ray observations of the Toothbrush cluster
• Deep radio observations of the radio halo of the bullet cluster 1E 0657-55.8
• Do radio relics challenge diffusive shock acceleration?
• Low-Frequency study of two clusters of galaxies: A2744 and A2219
• The Radio Relics and Halo of El Gordo, a Massive $z=0.870$ Cluster Merger
• Constraining the efficiency of cosmic ray acceleration by cluster shocks
• A $\mathcal{M}\gtrsim 3$ shock in `El Gordo' cluster and the origin of the radio relic
• Discovery of spectral curvature in the shock downstream region: CIZA J2242.8+5301
• Spectral and polarization study of the double relics in Abell 3376 using the GMRT and the VLA
• A shock front at the radio relic of Abell 2744
• An X-ray/optical study of the complex dynamics of the core of the massive intermediate-redshift cluster MACSJ0717.5+3745
• $Suzaku$ X-ray study of the double radio relic galaxy cluster CIZA J2242.8+5301
• XMM-Newton observations of the merging galaxy cluster CIZA J2242.8+5301
• A plethora of diffuse steep spectrum radio sources in Abell 2034 revealed by LOFAR
• Deep multi-frequency rotation measure tomography of the galaxy cluster A2255
• Diffuse radio emission in the merging cluster MACS J0717.5+3745: the discovery of the most powerful radio halo
• Relics in galaxy clusters at high radio frequencies
• Chandra and JVLA observations of HST Frontier Fields cluster MACS J0717.5+3745
• The widest-frequency radio relic spectra: observations from 150 MHz to 30 GHz
• Low Frequency VLA Observations of Abell 754: Evidence for a Cluster Radio Halo and Possible Radio Relics
• First X-ray evidence for a shock at the Coma relic
• Shock acceleration of electrons in the presence of synchrotron losses: I. test particle theory
• Suzaku observations of the merging galaxy cluster Abell2255: The northeast radio relic
• X-Ray View of the Shock Front in the Merging Cluster Abell 3376 with Suzaku
• The radio relic in Abell 2256: overall spectrum and implications for electron acceleration
• Radio spectral study of the cluster of galaxies Abell 2255
• A morphological comparison between giant radio halos and radio mini--halos in galaxy clusters
• Curved Radio Spectra of Weak Cluster Shocks
• The first Murchison Widefield Array low frequency radio observations of cluster scale non-thermal emission: the case of Abell 3667
• Radio Galaxy NGC 1265 unveils the Accretion Shock onto the Perseus Galaxy Cluster
• Properties of the intracluster medium of Abell 3667 observed with Suzaku XIS
• Complex diffuse radio emission in the merging PLANCK ESZ cluster Abell 3411
• Turbulent Cosmic Ray Reacceleration at Radio Relics and Halos in Clusters of Galaxies
• A Merger Shock in Abell 2034
• Shock Acceleration Model for the Toothbrush Radio Relic
• Detection of diffuse radio emission in the galaxy clusters A800, A910, A1550, and CL1446+26
• A study of halo and relic radio emission in merging clusters using the Murchison Widefield Array
• Evidence for a pressure discontinuity at the position of the Coma relic from Planck Sunyaev-Zel'dovich effect data
• The energetics of giant radio galaxy lobes from inverse Compton scattering observations
• The nature of the giant diffuse non-thermal source in the A3411-A3412 complex
• A multi-frequency study of the SZE in giant radio galaxies
• A Chandra Observation of Abell 13: Investigating the Origin of the Radio Relic

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• Low-frequency radio study of MACS clusters at 610 and 235 MHz using the GMRT
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• Radio-relic and the diffuse emission trail discovered in a low mass galaxy cluster Abell 1697
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