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Self-similar energetics in large clusters of galaxies

Abstract

Massive galaxy clusters are filled with a hot, turbulent and magnetized intra-cluster medium. Still forming under the action of gravitational instability, they grow in mass by accretion of supersonic flows. These flows partially dissipate into heat through a complex network of large-scale shocks1, while residual transonic (near-sonic) flows create giant turbulent eddies and cascades2,3. Turbulence heats the intra-cluster medium4 and also amplifies magnetic energy by way of dynamo action5,6,7,8. However, the pattern regulating the transformation of gravitational energy into kinetic, thermal, turbulent and magnetic energies remains unknown. Here we report that the energy components of the intra-cluster medium are ordered according to a permanent hierarchy, in which the ratio of thermal to turbulent to magnetic energy densities remains virtually unaltered throughout the cluster’s history, despite evolution of each individual component and the drive towards equipartition of the turbulent dynamo. This result revolves around the approximately constant efficiency of turbulence generation from the gravitational energy that is freed during mass accretion, revealed by our computational model of cosmological structure formation3,9. The permanent character of this hierarchy reflects yet another type of self-similarity in cosmology10,11,12,13, while its structure, consistent with current data14,15,16,17,18, encodes information about the efficiency of turbulent heating and dynamo action.

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Figure 1: High-resolution simulation of a galaxy cluster in fully cosmological context.
Figure 2: Temporal evolution of turbulence.
Figure 3: Temporal evolution of magnetic field.

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References

  1. Miniati, F. et al. Properties of cosmic shock waves in large-scale structure formation. Astrophys. J. 542, 608–621 (2000)

    Article  CAS  ADS  Google Scholar 

  2. Vazza, F., Brunetti, G., Gheller, C., Brunino, R. & Brüggen, M. Massive and refined. II. The statistical properties of turbulent motions in massive galaxy clusters with high spatial resolution. Astron. Astrophys. 529, A17 (2011)

    Article  ADS  Google Scholar 

  3. Miniati, F. The Matryoshka run: a Eulerian refinement strategy to study the statistics of turbulence in virialized cosmic structures. Astrophys. J. 782, 21 (2014)

    Article  ADS  Google Scholar 

  4. Zhuravleva, I. et al. Turbulent heating in galaxy clusters brightest in X-rays. Nature 515, 85–87 (2014)

    Article  CAS  ADS  Google Scholar 

  5. Schlüter, A. & Biermann, I. Interstellare Magnetfelder. Z. Naturforsch. A 5, 237 (1950)

    Article  ADS  MathSciNet  Google Scholar 

  6. Cho, J., Vishniac, E. T., Beresnyak, A., Lazarian, A. & Ryu, D. Growth of magnetic fields induced by turbulent motions. Astrophys. J. 693, 1449–1461 (2009)

    Article  ADS  Google Scholar 

  7. Ryu, D., Kang, H., Cho, J. & Das, S. Turbulence and magnetic fields in the large-scale structure of the Universe. Science 320, 909–912 (2008)

    Article  CAS  ADS  Google Scholar 

  8. Beresnyak, A. Universal nonlinear small-scale dynamo. Phys. Rev. Lett. 108, 035002 (2012)

    Article  CAS  ADS  Google Scholar 

  9. Miniati, F. The Matryoshka run. II. Time-dependent turbulence statistics, stochastic particle acceleration, and microphysics impact in a massive galaxy cluster. Astrophys. J. 800, 60 (2015)

    Article  ADS  Google Scholar 

  10. Harrison, E. R. Fluctuations at the threshold of classical cosmology. Phys. Rev. D 1, 2726–2730 (1970)

    Article  ADS  Google Scholar 

  11. Kaiser, N. Evolution and clustering of rich clusters. Mon. Not. R. Astron. Soc. 222, 323–345 (1986)

    Article  CAS  ADS  Google Scholar 

  12. Navarro, J. F., Frenk, C. S. & White, S. D. M. A universal density profile from hierarchical clustering. Astrophys. J. 490, 493–508 (1997)

    Article  ADS  Google Scholar 

  13. Moore, B. et al. Dark matter substructure within galactic halos. Astrophys. J. 524, L19–L22 (1999)

    Article  CAS  ADS  Google Scholar 

  14. Clarke, T. E., Kronberg, P. P. & Böhringer, H. A new radio-X-ray probe of galaxy cluster magnetic fields. Astrophys. J. 547, L111–L114 (2001)

    Article  CAS  ADS  Google Scholar 

  15. Guidetti, D. et al. The intracluster magnetic field power spectrum in Abell 2382. Astron. Astrophys. 483, 699–713 (2008)

    Article  CAS  ADS  Google Scholar 

  16. Bonafede, A. et al. The Coma cluster magnetic field from Faraday rotation measures. Astron. Astrophys. 513, A30 (2010)

    Article  Google Scholar 

  17. Govoni, F. et al. Rotation measures of radio sources in hot galaxy clusters. Astron. Astrophys. 522, A105 (2010)

    Article  Google Scholar 

  18. Kuchar, P. & Enßlin, T. A. Magnetic power spectra from Faraday rotation maps. REALMAF and its use on Hydra A. Astron. Astrophys. 529, A13 (2011)

    Article  ADS  Google Scholar 

  19. Miniati, F. & Colella, P. Block structured adaptive mesh and time refinement for hybrid, hyperbolic + N-body systems. J. Comput. Phys. 227, 400–430 (2007)

    Article  ADS  MathSciNet  Google Scholar 

  20. Beresnyak, A. & Miniati, F. Turbulent amplification and structure of intracluster magnetic field. Astrophys. J (submitted)

  21. Landau, L. D. & Lifshitz, E. M. Fluid Mechanics 2nd edn (Course of Theoretical Physics, Butterworth, 1987)

    Google Scholar 

  22. Subramanian, K., Narasimha, D. & Chitre, S. M. Thermal generation of cosmological seed magnetic fields in ionization fronts. Mon. Not. R. Astron. Soc. 271, L15 (1994)

    Article  ADS  Google Scholar 

  23. Kulsrud, R. M., Cen, R., Ostriker, J. P. & Ryu, D. The protogalactic origin for cosmic magnetic fields. Astrophys. J. 480, 481–491 (1997)

    Article  ADS  Google Scholar 

  24. Miniati, F. & Bell, A. R. Resistive magnetic field generation at cosmic dawn. Astrophys. J. 729, 73 (2011)

    Article  ADS  Google Scholar 

  25. Gregori, G. et al. Generation of scaled protogalactic seed magnetic fields in laser-produced shock waves. Nature 481, 480–483 (2012)

    Article  CAS  ADS  Google Scholar 

  26. Bertone, S., Vogt, C. & Enßlin, T. Magnetic field seeding by galactic winds. Mon. Not. R. Astron. Soc. 370, 319–330 (2006)

    Article  ADS  Google Scholar 

  27. Donnert, J., Dolag, K., Lesch, H. & Müller, E. Cluster magnetic fields from galactic outflows. Mon. Not. R. Astron. Soc. 392, 1008–1021 (2009)

    Article  ADS  Google Scholar 

  28. Stephens, I. W. et al. Spatially resolved magnetic field structure in the disk of a T Tauri star. Nature 514, 597–599 (2014)

    Article  CAS  ADS  Google Scholar 

  29. Bernet, M. L., Miniati, F., Lilly, S. J., Kronberg, P. P. & Dessauges-Zavadsky, M. Strong magnetic fields in normal galaxies at high redshift. Nature 454, 302–304 (2008)

    Article  CAS  ADS  Google Scholar 

  30. Zamaninasab, M., Clausen-Brown, E., Savolainen, T. & Tchekhovskoy, A. Dynamically important magnetic fields near accreting supermassive black holes. Nature 510, 126–128 (2014)

    Article  CAS  ADS  Google Scholar 

  31. Colella, P. Multidimensional upwind methods for hyperbolic conservation laws. J. Comput. Phys. 87, 171–200 (1990)

    Article  ADS  MathSciNet  Google Scholar 

  32. Miniati, F. & Martin, D. F. Constrained-transport magnetohydrodynamics with adaptive mesh refinement in CHARM. Astrophys. J. 195 (Suppl.), 5 (2011)

    Article  ADS  Google Scholar 

  33. Gaspari, M. & Churazov, E. Constraining turbulence and conduction in the hot ICM through density perturbations. Astron. Astrophys. 559, A78 (2013)

    Article  ADS  Google Scholar 

  34. Komatsu, E. et al. Five-year Wilkinson Microwave Anisotropy Probe observations: cosmological interpretation. Astrophys. J. 180 (Suppl.), 330–376 (2009)

    Article  Google Scholar 

  35. Eisenstein, D. J. & Hut, P. HOP: a new group-finding algorithm for N-body simulations. Astrophys. J. 498, 137–142 (1998)

    Article  ADS  Google Scholar 

  36. Eke, V. R., Navarro, J. F. & Steinmetz, M. The power spectrum dependence of dark matter halo concentrations. Astrophys. J. 554, 114–125 (2001)

    Article  ADS  Google Scholar 

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Acknowledgements

This work was supported by a grant from the Swiss National Supercomputing Center (CSCS) under project IDs S419 and S506.

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Authors and Affiliations

Authors

Contributions

F.M. carried out the cosmological simulations, computed the turbulence structure functions, derived equations (1), (2) and (3) and wrote most of the text. A.B. analysed the structure functions, testing the self-similar nature of second- and third-order structure functions within the inertial range and computing the dissipation rate. A.B. and F.M. computed the evolution of EB and LA.

Corresponding author

Correspondence to Francesco Miniati.

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The authors declare no competing financial interests.

Extended data figures and tables

Extended Data Figure 1 Generation and cascade of ICM hydromagnetic turbulence.

First the gravitational potential energy is converted into kinetic energy of accretion flows. These generate shear and shocks which, in addition to dissipation, produce fluid instabilities and a baroclinic term, respectively, leading to turbulent flows. Shocks also accelerate particles via the Fermi I mechanism. Shocks do not dissipate tangential flows, which will either generate turbulence, shear or shocks, or a combination thereof. The turbulence cascade includes dissipation of compressible modes at weak shocks, conversion of turbulent to magnetic energy via dynamo action, excitation of plasma waves accelerating relativistic particles via Fermi II mechanism, and viscous dissipation.

Extended Data Figure 2 Spectrum of ICM hydromagnetic turbulent cascade.

Characteristic spectrum of turbulent kinetic energy in the ICM. Solid and dashed lines correspond to the solenoidal (Kolmogorov-like) and the compressional (Burgers-like) velocity field, respectively. On the x axis, from left to right, we have marked the virial scale, Rvir, the injection scale, L, the Ozmidov’s scale, LO, the Alfvén scale, LA, and Kolmogorov’s dissipation scale, diss. All quantities are time dependent and Ozmidov’s scale is comparable to the injection scale, so at times turbulence in the radial direction could be suppressed by stratification.

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Miniati, F., Beresnyak, A. Self-similar energetics in large clusters of galaxies. Nature 523, 59–62 (2015). https://doi.org/10.1038/nature14552

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