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.

The signature of the first stars in atomic hydrogen at redshift 20

Abstract

Dark and baryonic matter moved at different velocities in the early Universe, which strongly suppressed star formation in some regions1. This was estimated2 to imprint a large-scale fluctuation signal of about two millikelvin in the 21-centimetre spectral line of atomic hydrogen associated with stars at a redshift of 20, although this estimate ignored the critical contribution of gas heating due to X-rays3,4 and major enhancements of the suppression. A large velocity difference reduces the abundance of haloes1,5,6 and requires the first stars to form in haloes of about a million solar masses7,8, substantially greater than previously expected9,10. Here we report a simulation of the distribution of the first stars at redshift 20 (cosmic age of around 180 million years), incorporating all these ingredients within a 400-megaparsec box. We find that the 21-centimetre hydrogen signature of these stars is an enhanced (ten millikelvin) fluctuation signal on the hundred-megaparsec scale, characterized2 by a flat power spectrum with prominent baryon acoustic oscillations. The required sensitivity to see this signal is achievable with an integration time of a thousand hours with an instrument like the Murchison Wide-field Array11 or the Low Frequency Array12 but designed to operate in the range of 50–100 megahertz.

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

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: The effect of relative velocity on the distribution of star-forming haloes at z = 20.
Figure 2: The effect of relative velocity on the distribution of star-forming haloes at z = 40.
Figure 3: The effect of relative velocity on the 21-cm brightness temperature at z = 20.
Figure 4: The signature of relative velocity in the 21-cm power spectrum at z = 20.

References

  1. Tseliakhovich, D. & Hirata, C. Relative velocity of dark matter and baryonic fluids and the formation of the first structures. Phys. Rev. D 82, 083520 (2010)

    Article  ADS  Google Scholar 

  2. Dalal, N., Pen, U.-L. & Seljak, U. Large-scale BAO signatures of the smallest galaxies. J. Cosmol. Astroparticle Phys. 11, 007 (2010)

    Article  ADS  Google Scholar 

  3. Madau, P., Meiksin, A. & Rees, M. J. 21 centimeter tomography of the intergalactic medium at high redshift. Astrophys. J. 475, 429–444 (1997)

    Article  ADS  Google Scholar 

  4. Pritchard, J. R. & Furlanetto, S. 21-cm fluctuations from inhomogeneous X-ray heating before reionization. Mon. Not. R. Astron. Soc. 376, 1680–1694 (2007)

    Article  CAS  ADS  Google Scholar 

  5. Maio, U., Koopmans, L. V. E. & Ciardi, B. The impact of primordial supersonic flows on early structure formation, reionization and the lowest-mass dwarf galaxies. Mon. Not. R. Astron. Soc. 412, L40–L44 (2011)

    Article  ADS  Google Scholar 

  6. Naoz, S., Yoshida, N. & Gnedin, N. Y. Simulations of early baryonic structure formation with stream velocity: I. Halo abundance. Astrophys. J. 747, 128 (2012)

    Article  ADS  Google Scholar 

  7. Stacy, A., Bromm, C. & Loeb, A. Effect of streaming motion of baryons relative to dark matter on the formation of the first stars. Astrophys. J. 730, L1 (2011)

    Article  ADS  Google Scholar 

  8. Greif, T., White, S., Klessen, R. & Springel, V. The delay of population III star formation by supersonic streaming velocities. Astrophys. J. 736, 147 (2011)

    Article  ADS  Google Scholar 

  9. Abel, T., Bryan, G. L. & Norman, M. L. The formation of the first star in the Universe. Science 295, 93–98 (2002)

    Article  CAS  ADS  Google Scholar 

  10. Bromm, V., Coppie, P. S. & Larson, R. B. Forming the first stars in the Universe: The fragmentation of primordial gas. Astrophys. J. 527, L5–L8 (1999)

    Article  CAS  ADS  Google Scholar 

  11. Bowman, J. D., Morales, M. F. & Hewitt, J. N. Foreground contamination in interferometric measurements of the redshifted 21 cm power spectrum. Astrophys. J. 695, 183–199 (2009)

    Article  ADS  Google Scholar 

  12. Harker, G. et al. Power spectrum extraction for redshifted 21-cm Epoch of Reionization experiments: the LOFAR case. Mon. Not. R. Astron. Soc. 405, 2492–2504 (2010)

    ADS  Google Scholar 

  13. Tseliakhovich, D., Barkana, R. & Hirata, C. Suppression and spatial variation of early galaxies and minihalos. Mon. Not. R. Astron. Soc. 418, 906–915 (2011)

    Article  ADS  Google Scholar 

  14. Fialkov, A., Barkana, R., Tseliakhovich, D. & Hirata, C. Impact of the Relative Motion between Dark Matter and Baryons on the First Stars. Mon. Not. R. Astron. Soc. (submitted); preprint at http://arxiv.org/abs/1110.2111.

  15. Naoz, S., Noter, S. & Barkana, R. The first stars in the Universe. Mon. Not. R. Astron. Soc. 373, L98–L102 (2006)

    Article  ADS  Google Scholar 

  16. Holzbauer, L. N. & Furlanetto, S. R. Fluctuations in the high-redshift Lyman-Werner and Lyman-alpha radiation backgrounds. Mon. Not. R. Astron. Soc. 419, 718–731 (2012)

    Article  CAS  ADS  Google Scholar 

  17. Mesinger, A., Furlanetto, S. & Cen, R. 21CMFAST: a fast, seminumerical simulation of the high-redshift 21-cm signal. Mon. Not. R. Astron. Soc. 411, 955–972 (2011)

    Article  ADS  Google Scholar 

  18. Barkana, R. & Loeb, A. Unusually large fluctuations in the statistics of galaxy formation at high redshift. Astrophys. J. 609, 474–481 (2004)

    Article  CAS  ADS  Google Scholar 

  19. Aihara, H. et al. The eighth data release of the Sloan Digital Sky Survey: first data from SDSS-III. Astrophys. J. Suppl. 193, 29 (2011); erratum. 195, 26 (2011)

    Article  ADS  Google Scholar 

  20. Colless, M. et al. The 2dF Galaxy Redshift Survey: spectra and redshifts. Mon. Not. R. Astron. Soc. 328, 1039–1063 (2001)

    Article  ADS  Google Scholar 

  21. Springel, V., Frenk, C. S. & White, S. D. M. The large-scale structure of the Universe. Nature 440, 1137–1144 (2006)

    Article  CAS  ADS  Google Scholar 

  22. Haiman, Z., Rees, M. J. & Loeb, A. Destruction of molecular hydrogen during cosmological reionization. Astrophys. J. 476, 458–463 (1997); erratum. 484, 985 (1997)

    Article  CAS  ADS  Google Scholar 

  23. Barkana, R. & Loeb, A. Detecting the earliest galaxies through two new sources of 21 centimeter fluctuations. Astrophys. J. 626, 1–11 (2005)

    Article  CAS  ADS  Google Scholar 

  24. Naoz, S. & Barkana, R. Detecting early galaxies through their 21-cm signature. Mon. Not. R. Astron. Soc. 385, L63–L67 (2008)

    Article  ADS  Google Scholar 

  25. Furlanetto, S. R., Oh, S. P. & Briggs, F. H. Cosmology at low frequencies: the 21 cm transition and the high-redshift Universe. Phys. Rep. 433, 181–301 (2006)

    Article  CAS  ADS  Google Scholar 

  26. Bouwens, R. J. et al. A candidate redshift z ≈ 10 galaxy and rapid changes in that population at an age of 500 Myr. Nature 469, 504–507 (2011)

    Article  CAS  ADS  Google Scholar 

  27. Anderson, L. et al. The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: baryon acoustic oscillations in the Data Release 9 Spectroscopic Galaxy Sample. Preprint at http://arxiv.org/abs/1203.6594 (2012)

  28. Barkana, R., Haiman, Z. & Ostriker, J. P. Constraints on warm dark matter from cosmological reionization. Astrophys. J. 558, 482–496 (2001)

    Article  CAS  ADS  Google Scholar 

  29. McQuinn, M., Zahn, O., Zaldarriaga, M., Hernquist, L. & Furlanetto, S. R. Cosmological parameter estimation using 21 cm radiation from the epoch of reionization. Astrophys. J. 653, 815–834 (2006)

    Article  CAS  ADS  Google Scholar 

  30. Liu, A. & Tegmark, M. How well can we measure and understand foregrounds with 21-cm experiments? Mon. Not. R. Astron. Soc. 419, 3491 (2012)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

This work was supported by the Israel Science Foundation (for R.B., and E.V.’s stay at Tel Aviv University) and by the European Research Council (for A.F.). D.T. and C.M.H. were supported by the US Department of Energy and the National Science Foundation. C.M.H. is also supported by the David & Lucile Packard Foundation.

Author information

Authors and Affiliations

Authors

Contributions

R.B. initiated the project, and E.V. made the computations and figures by developing a code, parts of which were based on codes supplied by A.F., D.T. and C.M.H. The text was written by R.B. and edited by the other authors. A.F. added the L–W module for Supplementary section 3 and made Supplementary Fig. 1.

Corresponding authors

Correspondence to Eli Visbal or Rennan Barkana.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Text and Data 1-4, which comprises 1) a description of the simulation code; 2) a comparison with previous work on the dark matter to baryon velocity difference; 3) the expected timing of the three high-redshift feedback transitions and 4) observational considerations. Supplementary Figure 1 (on the Lyman-Werner feedback) and additional references are also included. (PDF 252 kb)

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Visbal, E., Barkana, R., Fialkov, A. et al. The signature of the first stars in atomic hydrogen at redshift 20. Nature 487, 70–73 (2012). https://doi.org/10.1038/nature11177

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature11177

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