Probing the Epoch of Early Baryonic Infall Through 21cm Fluctuations

Preprint

20 July 2005

preprint
Published by arXiv in arXiv

https://doi.org/10.48550/arXiv.astro-ph/0502083

Abstract

After cosmological recombination, the primordial hydrogen gas decoupled from the cosmic microwave background (CMB) and fell into the gravitational potential wells of the dark matter. The neutral hydrogen imprinted acoustic oscillations on the pattern of brightness fluctuations due to its redshifted 21cm absorption of the CMB. Unlike CMB temperature fluctuations which probe the power spectrum at cosmic recombination, we show that observations of the 21cm fluctuations at z ~ 20-200 can measure four separate fluctuation modes (with a fifth mode requiring very high precision), thus providing a unique probe of the geometry and composition of the universe.

Keywords

21CM FLUCTUATIONS
BARYONIC INFALL
EARLY BARYONIC
RECOMBINATION
DARK MATTER
IMPRINTED
HYDROGEN
COSMIC
CMB

All Related Versions

Version 1, 2005-02-03, ArXiv
Version 2, 2005-07-20, ArXiv
Published version: Monthly Notices of the Royal Astronomical Society: Letters, 363 (1), L36.

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