A Powerful Radio Halo in the Hottest Known Cluster of Galaxies 1E 0657−56

Liang, Haida; Hunstead, R. W.; Birkinshaw, Mark; Andreani, P.

doi:10.1086/317223

Cited by 238 publications

(397 citation statements)

References 37 publications

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“…This is also supported by the strong correlation between radio halo luminosity and the host cluster X-ray luminosity (the RXLC, Liang et al 2000;Feretti 1999, also see Fig. 1).…”

Section: Cluster Radio Halosmentioning

confidence: 54%

The radio luminosity function of cluster radio halos

Enßlin

Roettgering²

2002

A&A

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Abstract. A significant fraction of galaxy clusters exhibits cluster-wide radio halos. We give a simple prediction of the local and higher redshift radio halo luminosity function (RHLF) on the basis of (i) an observed and a theoretical X-ray cluster luminosity function (XCLF) (ii) the observed radio-X-ray luminosity correlation (RXLC) of galaxy clusters with radio halos (iii) an assumed fraction of f rh ≈ 1 3 galaxy clusters to have radio halos as supported by observations. We then find 300-700 radio halos with S 1.4 GHz > 1 mJy, and 10 5 -10 6 radio halos with S 1.4 GHz > 1 µJy should be visible on the sky. 14% of the S 1.4 GHz > 1 mJy and 56% of the S 1.4 GHz > 1 µJy halos are located at z > 0.3. Subsequently, we give more realistic predictions taking into account (iv) a refined estimate of the radio halo fraction as a function of redshift and cluster mass, and (v) a decrease in intrinsic radio halo luminosity with redshift due to increased inverse Compton electron energy losses on the Cosmic Microwave Background (CMB). We find that this reduces the radio halo counts from the simple prediction by only 30 % totally, but the high redshift (z > 0.3) counts are more strongly reduced by 50-70%. These calculations show that the new generation of sensitive radio telescopes, including LOFAR, ATA, EVLA, SKA and the already-operating GMRT should be able to detect large numbers of radio halos and will provide unique information for studies of galaxy cluster merger rates and associated non-thermal processes.

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“…This is also supported by the strong correlation between radio halo luminosity and the host cluster X-ray luminosity (the RXLC, Liang et al 2000;Feretti 1999, also see Fig. 1).…”

Section: Cluster Radio Halosmentioning

confidence: 54%

The radio luminosity function of cluster radio halos

Enßlin

Roettgering²

2002

A&A

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“…The former are predominantly found in clusters showing merger activities whereas the latter are found in very relaxed clusters which developed a cool core, which harbors the mini-halo. The radio luminosity of giant halos seems to be strongly correlated with the X-ray emissivity of the cluster (Liang et al 2000;Brunetti et al 2009, and see Fig. 1).…”

Section: Observational Propertiesmentioning

confidence: 86%

Cosmic ray transport in galaxy clusters: implications for radio halos, gamma-ray signatures, and cool core heating

Enßlin

Pfrommer

Miniati

et al. 2011

A&A

202

294

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We investigate the interplay of cosmic ray (CR) propagation and advection in galaxy clusters. Propagation in form of CR diffusion and streaming tends to drive the CR radial profiles towards being flat, with equal CR number density everywhere. Advection of CR by the turbulent gas motions tends to produce centrally enhanced profiles. We assume that the CR streaming velocity is of the order of the sound velocity. This is motivated by plasma physical arguments. The CR streaming is then usually larger than typical advection velocities and becomes comparable or lower than this only for periods with trans-and super-sonic cluster turbulence. As a consequence a bimodality of the CR spatial distribution results. Strongly turbulent, merging clusters should have a more centrally concentrated CR energy density profile with respect to relaxed ones with very subsonic turbulence. This translates into a bimodality of the expected diffuse radio and gamma-ray emission of clusters, since more centrally concentrated CR will find higher target densities for hadronic CR proton interactions, higher plasma wave energy densities for CR electron and proton re-acceleration, and stronger magnetic fields. Thus, the observed bimodality of cluster radio halos appears to be a natural consequence of the interplay of CR transport processes, independent of the model of radio halo formation, be it hadronic interactions of CR protons or re-acceleration of low-energy CR electrons. Energy dependence of the CR propagation should lead to spectral steepening of dying radio halos. Furthermore, we show that the interplay of CR diffusion with advection implies first order CR re-acceleration in the pressure-stratified atmospheres of galaxy clusters. Finally, we argue that CR streaming could be important in turbulent cool cores of galaxy clusters since it heats preferentially the central gas with highest cooling rate.

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“…SZ intensity spectra G(x) = ΔI(x)/(I 0 y) for the cluster with the hard X-ray tail for DFs with and without the second electron population shown by the dashed and solid lines, respectively. values of 14.5 +2.0 −1.7 keV and 14.8 +1.7 −1.2 keV derived by using both ASCA and ROSAT (Liang et al 2000) and by using Chandra data (Markevitch et al 2002), respectively. Note that the total DF is normalized.…”

Section: Dfs In Galaxy Clusters With Hard X-ray Spectral Tailsmentioning

confidence: 99%

Can electron distribution functions be derived through the Sunyaev-Zel’dovich effect?

Prokhorov

Colafrancesco

Akahori

et al. 2011

A&A

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Aims. Measurements of the Sunyaev-Zel'dovich (hereafter SZ) effect distortion of the cosmic microwave background provide methods to derive the gas pressure and temperature of galaxy clusters. Here we study the ability of SZ effect observations to derive the electron distribution function (DF) in massive galaxy clusters. Methods. Our calculations of the SZ effect include relativistic corrections considered within the framework of the Wright formalism and use a decomposition technique of electron DFs into Fourier series. Using multi-frequency measurements of the SZ effect, we find the solution of a linear system of equations that is used to derive the Fourier coefficients; we further analyze different frequency samples to decrease uncertainties in Fourier coefficient estimations. Results. We propose a method to derive DFs of electrons using SZ multi-frequency observations of massive galaxy clusters. We found that the best frequency sample to derive an electron DF includes high frequencies ν = 375, 600, 700, 857 GHz. We show that it is possible to distinguish a Juttner DF from a Maxwell-Bolzman DF as well as from a Juttner DF with the second electron population by means of SZ observations for the best frequency sample if the precision of SZ intensity measurements is less than 0.1%. We demonstrate by means of 3D hydrodynamic numerical simulations of a hot merging galaxy cluster that the morphologies of SZ intensity maps are different for frequencies ν = 375, 600, 700, 857 GHz. We stress that measurements of SZ intensities at these frequencies are a promising tool for studying electron distribution functions in galaxy clusters.

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A Powerful Radio Halo in the Hottest Known Cluster of Galaxies 1E 0657−56

Cited by 238 publications

References 37 publications

The radio luminosity function of cluster radio halos

The radio luminosity function of cluster radio halos

Cosmic ray transport in galaxy clusters: implications for radio halos, gamma-ray signatures, and cool core heating

Can electron distribution functions be derived through the Sunyaev-Zel’dovich effect?

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