Open AccessObserving the reionization epoch through 21‐centimetre radiation
Author(s) -
Furlanetto Steven R.,
Sokasian Aaron,
Hernquist Lars
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.07187.x
Subject(s) - reionization , physics , astrophysics , brightness temperature , radiative transfer , dark ages , cosmic cancer database , brightness , astronomy , galaxy , redshift , optics
We study the observability of the reionization epoch through the 21‐cm hyperfine transition of neutral hydrogen. We use a high‐resolution cosmological simulation (including hydrodynamics) together with a fast radiative transfer algorithm to compute the evolution of 21‐cm emission from the intergalactic medium (IGM) in several different models of reionization. We show that the mean brightness temperature of the IGM drops from δ T b ∼ 25 mK to ∼10 −2 mK during overlap (over a frequency interval Δν∼ 25 MHz ), while the root mean square fluctuations on small scales drop abruptly from 〈δ T 2 b 〉 1/2 ∼ 10 mK to ∼10 −1 mK at the end of overlap. We show that 21‐cm observations can efficiently discriminate models with a single early reionization epoch from models with two distinct reionization episodes.