Open AccessProbing the epoch of early baryonic infall through 21‐cm fluctuations
Author(s) -
Barkana R.,
Loeb A.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society: letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.067
H-Index - 122
eISSN - 1745-3933
pISSN - 1745-3925
DOI - 10.1111/j.1745-3933.2005.00079.x
Subject(s) - cosmic microwave background , physics , astrophysics , redshift , baryon acoustic oscillations , dark matter , universe , cosmic cancer database , spectral density , baryon , gravitation , physical cosmology , cosmic background radiation , astronomy , dark energy , cosmology , galaxy , optics , statistics , mathematics , anisotropy
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 21‐cm absorption of the CMB. Unlike CMB temperature fluctuations which probe the power spectrum at cosmic recombination, we show that observations of the 21‐cm 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.