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The observable signature of late heating of the Universe during cosmic reionization

Abstract

Models and simulations1,2,3,4 of the epoch of reionization predict that spectra of the 21-centimetre transition of atomic hydrogen will show a clear fluctuation peak, at a redshift and scale, respectively, that mark the central stage of reionization and the characteristic size of ionized bubbles. This is based on the assumption5,6,7 that the cosmic gas was heated by stellar remnants—particularly X-ray binaries—to temperatures well above the cosmic microwave background at that time (about 30 kelvin). Here we show instead that the hard spectra (that is, spectra with more high-energy photons than low-energy photons) of X-ray binaries8,9 make such heating ineffective, resulting in a delayed and spatially uniform heating that modifies the 21-centimetre signature of reionization. Rather than looking for a simple rise and fall of the large-scale fluctuations (peaking at several millikelvin), we must expect a more complex signal also featuring a distinct minimum (at less than a millikelvin) that marks the rise of the cosmic mean gas temperature above the microwave background. Observing this signal, possibly with radio telescopes in operation today, will demonstrate the presence of a cosmic background of hard X-rays at that early time.

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Figure 1: X-ray spectra, mean free paths, and horizons.
Figure 2: The global 21-cm spectrum.
Figure 3: The 21-cm power spectrum.

References

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

    ADS  CAS  Google Scholar 

  2. Furlanetto, S. R., Zaldarriaga, M. & Hernquist, L. The growth of H II regions during reionization. Astrophys. J. 613, 1–15 (2004)

    ADS  CAS  Google Scholar 

  3. Mellema, G., Iliev, I. T., Pen, U.-L. & Shapiro, P. R. Simulating cosmic reionization at large scales—II. The 21-cm emission features and statistical signals. Mon. Not. R. Astron. Soc. 372, 679–692 (2006)

    ADS  CAS  Google Scholar 

  4. Zahn, O. et al. Simulations and analytic calculations of bubble growth during hydrogen reionization. Astrophys. J. 654, 12–26 (2007)

    ADS  CAS  Google Scholar 

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

    ADS  Google Scholar 

  6. Furlanetto, S. R. The global 21-centimeter background from high redshifts. Mon. Not. R. Astron. Soc. 371, 867–878 (2006)

    ADS  CAS  Google Scholar 

  7. 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)

    ADS  CAS  Google Scholar 

  8. Fragos, T. et al. X-ray binary evolution across cosmic time. Astrophys. J. 764, 41 (2013)

    ADS  Google Scholar 

  9. Fragos, T. et al. Energy feedback from X-ray binaries in the early Universe. Astrophys. J. 776, L31 (2013)

    ADS  Google Scholar 

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

    ADS  CAS  Google Scholar 

  11. Christian, P. & Loeb, A. Measuring the X-ray background in the reionization era with first generation 21 cm experiments. J. Cosmol. Astroparticle Phys. 09, 014 (2013)

    ADS  Google Scholar 

  12. 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)

    ADS  Google Scholar 

  13. Mesinger, A., Ferrara, A. & Spiegel, D. S. Signatures of X-rays in the early Universe. Mon. Not. R. Astron. Soc. 431, 621–637 (2013)

    ADS  CAS  Google Scholar 

  14. Bennett, C. L. et al. Nine-year Wilkinson Microwave Anisotropy Probe (WMAP) observations: final maps and results. Astrophys. J. 208 (suppl.). 20 (2013)

    Google Scholar 

  15. Planck Collaboration Planck 2013 results. XVI. Cosmological parameters. Preprint at http://arxiv.org/abs/1303.5076 (2013)

  16. Schroeder, J., Mesinger, A. & Haiman, Z. Evidence of Gunn-Peterson damping wings in high-z quasar spectra: strengthening the case for incomplete reionization at z 6−7. Mon. Not. R. Astron. Soc. 428, 3058–3071 (2013)

    ADS  CAS  Google Scholar 

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

    ADS  CAS  Google Scholar 

  18. Ahn, K. et al. Detecting the rise and fall of the first stars by their impact on cosmic reionization. Astrophys. J. 756, L16 (2012)

    ADS  Google Scholar 

  19. Fialkov, A., Barkana, R., Visbal, E., Tseliakhovich, D. & Hirata, C. M. The 21-cm signature of the first stars during the Lyman-Werner feedback era. Mon. Not. R. Astron. Soc. 432, 2909–2916 (2013)

    ADS  CAS  Google Scholar 

  20. Dekel, A. & Silk, J. The origin of dwarf galaxies, cold dark matter, and biased galaxy formation. Astrophys. J. 303, 39–55 (1986)

    ADS  CAS  Google Scholar 

  21. Wyithe, J. S. B. & Loeb, A. A suppressed contribution of low-mass galaxies to reionization due to supernova feedback. Mon. Not. R. Astron. Soc. 428, 2741–2754 (2013)

    ADS  Google Scholar 

  22. Visbal, E., Barkana, R., Fialkov, A., Tseliakhovich, D. & Hirata, C. M. The signature of the first stars in atomic hydrogen at redshift 20. Nature 487, 70 (2012)

    ADS  CAS  PubMed  Google Scholar 

  23. 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)

    ADS  CAS  Google Scholar 

  24. Parsons, A. R. et al. New limits on 21cm EoR from PAPER-32 consistent with an X-ray heated IGM at z = 7.7. Preprint at http://arxiv.org/abs/1304.4991 (2013)

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

    ADS  CAS  Google Scholar 

  26. Fialkov, A., Barkana, R., Pinhas, A. & Visbal, E. Complete history of the observable 21-cm signal from the first stars during the pre-reionization era. Mon. Not. R. Astron. Soc. 437, L36–L40 (2014)

    ADS  CAS  Google Scholar 

  27. McClintock, J. E. & Remillard, R. A. in Compact Stellar X-Ray Sources (eds Lewin, W. & van der Klis, M. ) 157–213 (Cambridge Astrophys. Ser. 157, Cambridge Univ. Press, 2006)

    Google Scholar 

  28. Tamura, M. et al. The truncated disk from Suzaku data of GX 339–4 in the extreme very high state. Astrophys. J. 753, 65 (2012)

    ADS  Google Scholar 

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

    ADS  Google Scholar 

  30. Fialkov, A., Barkana, R., Tseliakhovich, D. & Hirata, C. Impact of the relative motion between dark matter and baryons on the first stars: semi-analytical modelling. Mon. Not. R. Astron. Soc. 424, 1335–1345 (2012)

    ADS  Google Scholar 

  31. Barkana, R. & Loeb, A. In the beginning: the first sources of light and the reionization of the Universe. Phys. Rep. 349, 125–238 (2001)

    ADS  CAS  Google Scholar 

  32. 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)

    ADS  Google Scholar 

  33. Furlanetto, S. R. & Stoever, S. J. Secondary ionization and heating by fast electrons. Mon. Not. R. Astron. Soc. 404, 1869 (2010)

    ADS  CAS  Google Scholar 

  34. Verner, D. A., Ferland, G. J., Korista, K. T. & Yakovlev, D. G. Atomic data for astrophysics. II. New analytic FITS for photoionization cross sections of atoms and ions. Astrophys. J. 465, 487 (1996)

    ADS  CAS  Google Scholar 

  35. Hirata, C. M. Wouthuysen-Field coupling strength and application to high-redshift 21-cm radiation. Mon. Not. R. Astron. Soc. 367, 259–274 (2006)

    ADS  CAS  Google Scholar 

  36. Chuzhoy, L. & Shapiro, P. R. Ultraviolet pumping of hyperfine transitions in the light elements, with application to 21 cm hydrogen and 92 cm deuterium lines from the early Universe. Astrophys. J. 651, 1 (2006)

    ADS  CAS  Google Scholar 

  37. Wyithe, J. S. B. & Loeb, A. A characteristic size of 10 Mpc for the ionized bubbles at the end of cosmic reionization. Nature 432, 194 (2004)

    ADS  CAS  PubMed  Google Scholar 

  38. Safranek-Shrader, C., Milosavljevic, M. & Bromm, V. Star formation in the first galaxies—II: Clustered star formation and the influence of metal line cooling. Preprint at http://arxiv.org/abs/1307.1982 (2013)

  39. Wise, J. H., Abel, T., Turk, M. J., Norman, M. L. & Smith, B. D. The birth of a galaxy—II. The role of radiation pressure. Mon. Not. R. Astron. Soc. 427, 311–326 (2012)

    ADS  CAS  Google Scholar 

  40. Mirabel, I. F., Dijkstra, M., Laurent, P., Loeb, A. & Pritchard, J. R. Stellar black holes at the dawn of the universe. Astron. Astrophys. 528, A149 (2011)

    ADS  Google Scholar 

  41. Basu-Zych, A. R. et al. The X-ray star formation story as told by Lyman break galaxies in the 4 Ms CDF-S. Astrophys. J. 762, 45 (2013)

    ADS  Google Scholar 

  42. Basu-Zych, A. R. et al. Evidence for elevated X-ray emission in local Lyman break galaxy analogs. Astrophys. J. 774, 152 (2013)

    ADS  Google Scholar 

  43. Gilfanov, M., Grimm, H.-J. & Sunyaev, R. L X -SFR relation in star-forming galaxies. Mon. Not. R. Astron. Soc. 347, L57 (2004)

    ADS  CAS  Google Scholar 

  44. Mineo, S., Gilfanov, M. & Sunyaev, R. X-ray emission from star-forming galaxies—II. Hot interstellar medium. Mon. Not. R. Astron. Soc. 426, 1870–1883 (2012)

    ADS  Google Scholar 

  45. Oh, S. P. Reionization by hard photons. I. X-rays from the first star clusters. Astrophys. J. 553, 499 (2001)

    ADS  CAS  Google Scholar 

  46. Vasudevan, R. V., Mushotzky, R. F. & Gandhi, P. Can we reproduce the X-ray background spectral shape using local active galactic nuclei? Astrophys. J. 770, L37 (2013)

    ADS  Google Scholar 

  47. Lützgendorf, N. et al. M•−σ relation for intermediate mass black holes in globular clusters. Astron. Astrophys. 555, A26 (2013)

    Google Scholar 

  48. Tanaka, T., Perna, R. & Haiman, Z. X-ray emission from high-redshift miniquasars: self-regulating the population of massive black holes through global warming. Mon. Not. R. Astron. Soc. 425, 2974–2987 (2012)

    ADS  Google Scholar 

  49. Ciardi, B., Salvaterra, R. & Di Matteo, T. Lyα versus X-ray heating in the high-z intergalactic medium. Mon. Not. R. Astron. Soc. 401, 2635–2640 (2010)

    ADS  CAS  Google Scholar 

  50. Wyithe, J. S. B. & Loeb, A. Self-regulated growth of supermassive black holes in galaxies as the origin of the optical and X-ray luminosity functions of quasars. Astrophys. J. 595, 614 (2003)

    ADS  Google Scholar 

  51. Sazonov, S., Yu, Ostriker, J. P. & Sunyaev, R. A. Quasars: the characteristic spectrum and the induced radiative heating. Mon. Not. R. Astron. Soc. 347, 144–156 (2004)

    ADS  CAS  Google Scholar 

  52. Volonteri, M. & Gnedin, N. Y. Relative role of stars and quasars in cosmic reionization. Astrophys. J. 703, 2113–2117 (2009)

    ADS  CAS  Google Scholar 

  53. McConnell, N. J. & Ma, C.-P. Revisiting the scaling relations of black hole masses and host galaxy properties. Astrophys. J. 764, 184 (2013)

    ADS  Google Scholar 

  54. Shakura, N. I. & Sunyaev, R. A. Black holes in binary systems. Observational appearance. Astron. Astrophys. 24, 337–355 (1973)

    ADS  Google Scholar 

  55. Chen, X. & Miralda-Escudé, J. The spin-kinetic temperature coupling and the heating rate due to Lyα scattering before reionization: predictions for 21 centimeter emission and absorption. Astrophys. J. 602, 1–11 (2004)

    ADS  CAS  Google Scholar 

  56. Chuzhoy, L. & Shapiro, P. R. Heating and cooling of the early intergalactic medium by resonance photons. Astrophys. J. 655, 843–846 (2007)

    ADS  CAS  Google Scholar 

  57. Furlanetto, S. R. & Loeb, A. Large-scale structure shocks at low and high redshifts. Astrophys. J. 611, 642–654 (2004)

    ADS  CAS  Google Scholar 

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Acknowledgements

We are grateful to S. Naoz for drawing our attention to the work of T. Fragos, who provided us with detailed model spectra of X-ray binaries, which helped motivate this study. This work was supported by Israel Science Foundation grant number 823/09, and by the LabEx ENS-ICFP (grant numbers ANR-10-LABX-0010 and ANR-10-IDEX-0001-02 PSL*).

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Authors

Contributions

R.B. initiated the project. A.F. developed and ran the simulations and made the figures by substantially extending a code that was originally developed by E.V. working with R.B. The text was written by R.B. and edited by the other authors.

Corresponding authors

Correspondence to Anastasia Fialkov or Rennan Barkana.

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The authors declare no competing financial interests.

Extended data figures and tables

Extended Data Figure 1 The 21-cm power spectrum versus redshift.

We show the same data as in Fig. 3 (with the same nomenclature), but as a function of 1 + z, where z is the redshift, a direct observable (given that the observed wavelength is 21(1 + z) cm). This presentation has the advantage of clearly separating out the early and late reionization cases, while showing that reionization does not affect the redshift of the new minimum (solid curves) at k = 0.5 Mpc−1. Indeed, this minimum marks the cosmic heating transition (to within 2% in redshift in all our model calculations), while the minimum at k = 0.1 Mpc−1 is typically delayed owing to the evolving power spectrum shape (see Extended Data Fig. 2). We consider wavenumbers k = 0.1 Mpc−1 (a and b) and k = 0.5 Mpc−1 (c and d), for each of our two cases for galactic halos, atomic cooling (a and c) or massive halos (b and d). The results shown (here and in Fig. 3) correspond to a total of four different reionization histories. Late reionization with atomic cooling reaches 1/4, 1/2, 3/4 and full reionization at z = 10.7, 8.7, 7.7 and 7.0; the corresponding redshifts for early reionization are 11.8, 10.0, 9.1 and 8.4. Massive halos give a sharper reionization transition, with late reionization advancing through z = 10.3, 8.9, 8.3 and 7.7, while early reionization corresponds to z = 11.4, 10.2, 9.7 and 9.0.

Extended Data Figure 2 Full 21-cm power spectra.

We show examples of full power spectra corresponding to the data shown in Fig. 3 and Extended Data Fig. 1, for the cases with fX = 1 and late reionization. We compare the new XRB spectrum9 (solid curves) to the previously adopted soft spectrum (dashed curves), and show the saturated heating case for reference (dotted curves). We consider atomic cooling (a) or massive halos (b). In order of increasing cosmic age, we consider three key moments (which fall at different redshifts for the various cases, based on Extended Data Fig. 1): the minimum fluctuation at k = 0.5 Mpc−1 (blue curves), the minimum at k = 0.1 Mpc−1 (green curves), and the midpoint of reionization (red curves). For the new spectrum, strong evolution is predicted in the power spectrum shape, because large-scale fluctuations from X-ray heating dominate (up to k ≈ 0.5 Mpc−1) at the heating transition (blue solid curves) but then rapidly decline so that density fluctuations come to dominate (at k > 0.1 Mpc−1 at the time shown in green solid curves), with an eventual large-scale boost by the ionized bubbles (red solid curves).

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Fialkov, A., Barkana, R. & Visbal, E. The observable signature of late heating of the Universe during cosmic reionization. Nature 506, 197–199 (2014). https://doi.org/10.1038/nature12999

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