The 21-cm signature of the first stars during the Lyman-Werner feedback era

Anastasia Fialkov, Rennan Barkana, Eli Visbal, Dmitriy Tseliakhovich, Christopher M. Hirata

Research output: Contribution to journalArticlepeer-review


The formation of the first stars is an exciting frontier area in astronomy. Early redshifts (z ~ 20) have become observationally promising as a result of a recently recognized effect of a supersonic relative velocity between the dark matter and gas. This effect produces prominent structure on 100 comoving Mpc scales, which makes it much more feasible to detect 21-cm fluctuations from the epoch of first heating. We use semi-numerical hybrid methods to follow for the first time the joint evolution of the X-ray and Lyman"CWerner radiative backgrounds, including the effect of the supersonic streaming velocity on the cosmic distribution of stars. We incorporate self-consistently the negative feedback on star formation induced by the Lyman"CWerner radiation, which dissociates molecular hydrogen and thus suppresses gas cooling. We find that the feedback delays the X-ray heating transition by δz ~ 2, but leaves a promisingly large fluctuation signal over a broad redshift range. The large-scale power spectrum is predicted to reach a maximal signal-to-noise ratio of S/N ~ 3-4 at z ~ 18 (for a projected first-generation instrument), with S/N > 1 out to z ~ 22-23. We hope to stimulate additional numerical simulations as well as observational efforts focused on the epoch prior to cosmic reionization.

Original languageEnglish
Pages (from-to)2909-2916
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
StatePublished - Oct 2013


  • Cosmology: theory
  • Galaxies: Formation
  • Galaxies: High-redshift
  • Intergalactic medium


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