Visbal, Eli and Barkana, Rennan and Fialkov, Anastasia and Tseliakhovich, Dmitriy and Hirata, Christopher M. (2012) The signature of the first stars in atomic hydrogen at redshift 20. Nature, 487 (7405). pp. 70-73. ISSN 0028-0836 http://resolver.caltech.edu/CaltechAUTHORS:20120723-092449244
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Dark and baryonic matter moved at different velocities in the early Universe, which strongly suppressed star formation in some regions. This was estimated 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-rays and major enhancements of the suppression. A large velocity difference reduces the abundance of haloes and requires the first stars to form in haloes of about a million solar masses, substantially greater than previously expected. 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, characterized 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 Array or the Low Frequency Array but designed to operate in the range of 50–100 megahertz.
|Additional Information:||© 2012 Macmillan Publishers Limited. Received 03 January 2012; Accepted 24 April 2012; Published online 20 June 2012. 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 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.|
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|Deposited By:||Tony Diaz|
|Deposited On:||23 Jul 2012 22:35|
|Last Modified:||17 Sep 2012 19:14|
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