Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Clumps and streams in the local dark matter distribution

Abstract

In cold dark matter cosmological models1,2, structures form and grow through the merging of smaller units3. Numerical simulations have shown that such merging is incomplete; the inner cores of haloes survive and orbit as ‘subhaloes’ within their hosts4,5. Here we report a simulation that resolves such substructure even in the very inner regions of the Galactic halo. We find hundreds of very concentrated dark matter clumps surviving near the solar circle, as well as numerous cold streams. The simulation also reveals the fractal nature of dark matter clustering: isolated haloes and subhaloes contain the same relative amount of substructure and both have cusped inner density profiles. The inner mass and phase-space densities of subhaloes match those of recently discovered faint, dark-matter-dominated dwarf satellite galaxies6,7,8, and the overall amount of substructure can explain the anomalous flux ratios seen in strong gravitational lenses9,10. Subhaloes boost γ-ray production from dark matter annihilation by factors of 4 to 15 relative to smooth galactic models. Local cosmic ray production is also enhanced, typically by a factor of 1.4 but by a factor of more than 10 in one per cent of locations lying sufficiently close to a large subhalo. (These estimates assume that the gravitational effects of baryons on dark matter substructure are small.)

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Via Lactea II projected dark matter squared-density map.
Figure 2: Density profiles of main halo and subhaloes.
Figure 3: Subhalo and sub-subhalo abundances.

References

  1. Peebles, P. J. E. Large-scale background temperature and mass fluctuations due to scale-invariant primeval perturbations. Astrophys. J. 263, L1–L5 (1982)

    Article  ADS  CAS  Google Scholar 

  2. Blumenthal, G. R., Faber, S. M., Primack, J. R. & Rees, M. J. Formation of galaxies and large-scale structure with cold dark matter. Nature 311, 517–525 (1984)

    Article  ADS  CAS  Google Scholar 

  3. White, S. D. M. & Rees, M. J. Core condensation in heavy halos - A two-stage theory for galaxy formation and clustering. Mon. Not. R. Astron. Soc. 183, 341–358 (1978)

    Article  ADS  Google Scholar 

  4. Ghigna, S. et al. Dark matter haloes within clusters. Mon. Not. R. Astron. Soc. 300, 146–162 (1998)

    Article  ADS  CAS  Google Scholar 

  5. Klypin, A., Kravtsov, A. V., Valenzuela, O. & Prada, F. Where are the missing galactic satellites? Astrophys. J. 522, 82–92 (1999)

    Article  ADS  CAS  Google Scholar 

  6. Strigari, L. E. et al. The most dark matter dominated galaxies: Predicted gamma-ray signals from the faintest milky way dwarfs. Astrophys. J. 678, 614–620 (2008)

    Article  ADS  Google Scholar 

  7. Simon, J. D. & Geha, M. The kinematics of the ultra-faint milky way satellites: Solving the missing satellite problem. Astrophys. J. 670, 313–331 (2007)

    Article  ADS  CAS  Google Scholar 

  8. Belokurov, V. et al. Cats and dogs, hair and a hero: A quintet of new milky way companions. Astrophys. J. 654, 897–906 (2007)

    Article  ADS  Google Scholar 

  9. Dalal, N. & Kochanek, C. S. Direct detection of cold dark matter substructure. Astrophys. J. 572, 25–33 (2002)

    Article  ADS  CAS  Google Scholar 

  10. Metcalf, R. B., Moustakas, L. A., Bunker, A. J. & Parry, I. R. Spectroscopic gravitational lensing and limits on the dark matter substructure in Q2237+0305. Astrophys. J. 607, 43–59 (2004)

    Article  ADS  CAS  Google Scholar 

  11. Green, A. M., Hofmann, S. & Schwarz, D. J. The power spectrum of SUSY-CDM on subgalactic scales. Mon. Not. R. Astron. Soc. 353, L23–L27 (2004)

    Article  ADS  CAS  Google Scholar 

  12. Diemand, J., Moore, B. & Stadel, J. Earth-mass dark-matter haloes as the first structures in the early Universe. Nature 433, 389–391 (2005)

    Article  ADS  CAS  Google Scholar 

  13. Stadel, J. G. Cosmological N-body Simulations and Their Analysis. PhD thesis, Univ. Washington. (2001)

    Google Scholar 

  14. Spergel, D. N. et al. Three-year Wilkinson Microwave Anisotropy Probe (WMAP) observations: Implications for cosmology. Astrophys. J. Suppl. Ser 170, 377–408 (2007)

    Article  ADS  Google Scholar 

  15. Diemand, J., Kuhlen, M. & Madau, P. Formation and evolution of galaxy dark matter halos and their substructure. Astrophys. J. 667, 859–877 (2007)

    Article  ADS  Google Scholar 

  16. Belokurov, V. et al. The field of streams: Sagittarius and its siblings. Astrophys. J. 642, L137–L140 (2006)

    Article  ADS  Google Scholar 

  17. Mao, S. & Schneider, P. Evidence for substructure in lens galaxies? Mon. Not. R. Astron. Soc. 295, 587–594 (1998)

    Article  ADS  Google Scholar 

  18. Metcalf, R. B. & Madau, P. Compound gravitational lensing as a probe of dark matter substructure within galaxy halos. Astrophys. J. 563, 9–20 (2001)

    Article  ADS  Google Scholar 

  19. Zemp, M., Stadel, J., Moore, B. & Carollo, C. M. An optimum time-stepping scheme for N-body simulations. Mon. Not. R. Astron. Soc. 376, 273–286 (2007)

    Article  ADS  Google Scholar 

  20. Diemand, J., Moore, B. & Stadel, J. Convergence and scatter of cluster density profiles. Mon. Not. R. Astron. Soc. 353, 624–632 (2004)

    Article  ADS  Google Scholar 

  21. Kazantzidis, S. et al. Density profiles of cold dark matter substructure: Implications for the missing-satellites problem. Astrophys. J. 608, 663–679 (2004)

    Article  ADS  Google Scholar 

  22. Bullock, J. S. et al. Profiles of dark haloes: evolution, scatter and environment. Mon. Not. R. Astron. Soc. 321, 559–575 (2001)

    Article  ADS  Google Scholar 

  23. Ullio, P., Bergström, L., Edsjö, J. & Lacey, C. Cosmological dark matter annihilations into γ rays: A closer look. Phys. Rev. D 66, 123502 (2002)

    Article  ADS  Google Scholar 

  24. Colafrancesco, S., Profumo, S. & Ullio, P. Multi-frequency analysis of neutralino dark matter annihilations in the Coma cluster. Astron. Astrophys. 455, 21–43 (2006)

    Article  ADS  CAS  Google Scholar 

  25. Lavalle, J., Yuan, Q., Maurin, D. & Bi, X. Full calculation of clumpiness boost factors for antimatter cosmic rays in the light of ΛCDM N-body simulation results. Astron. Astrophys. 479, 427–452 (2008)

    Article  ADS  CAS  Google Scholar 

  26. Beatty, J. J. et al. New measurement of the cosmic-ray positron fraction from 5 to 15GeV. Phys. Rev. Lett. 93, 241102 (2004)

    Article  ADS  CAS  Google Scholar 

  27. Sharma, S. & Steinmetz, M. Multidimensional density estimation and phase-space structure of dark matter haloes. Mon. Not. R. Astron. Soc. 373, 1293–1307 (2006)

    Article  ADS  Google Scholar 

  28. Bertschinger, E. Multiscale Gaussian random fields and their application to cosmological simulations. Astrophys. J. Suppl. Ser. 137, 1–20 (2001)

    Article  ADS  Google Scholar 

  29. Navarro, J. F. et al. The inner structure of ΛCDM haloes - III. Universality and asymptotic slopes. Mon. Not. R. Astron. Soc. 349, 1039–1051 (2004)

    Article  ADS  CAS  Google Scholar 

  30. Reed, D. et al. Dark matter subhaloes in numerical simulations. Mon. Not. R. Astron. Soc. 359, 1537–1548 (2005)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

It is a pleasure to thank B. Messer and the Scientific Computing Group at the National Center for Computational Sciences for their help. The Via Lactea II simulation was performed at the Oak Ridge National Laboratory through an award from the US Department of Energy’s Office of Science as part of the 2007 Innovative and Novel Computational Impact on Theory and Experiment (INCITE) programme. Additional computations (initial conditions generation, code optimizations and smaller test runs) were carried out on the MareNostrum supercomputer at the BSC, on Columbia at NASA Ames and on the UCSC Astrophysics Supercomputer Pleiades. This work was supported by NASA and the Swiss National Science Foundation.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to J. Diemand.

Supplementary information

Supplementary information

The file contains Supplementary Notes and additional references, Supplementary Figures 1-2 with Legends and Supplementary Table 1. (PDF 118 kb)

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Cite this article

Diemand, J., Kuhlen, M., Madau, P. et al. Clumps and streams in the local dark matter distribution. Nature 454, 735–738 (2008). https://doi.org/10.1038/nature07153

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature07153

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing