Open AccessSecond order cross‐correlation between kinetic Sunyaev–Zel’dovich effect and 21‐cm fluctuations from the epoch of reionization
Author(s) -
Tashiro Hiroyuki,
Aghanim Nabila,
Langer Mathieu,
Douspis Marian,
Zaroubi Saleem,
Jelić Vibor
Publication year - 2011
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.1365-2966.2011.18644.x
Subject(s) - reionization , physics , cosmic microwave background , astrophysics , redshift , spectral density , sunyaev–zel'dovich effect , dark ages , amplitude , cosmic background radiation , kinetic energy , anisotropy , galaxy , statistics , mathematics , quantum mechanics
The measurement of the brightness temperature fluctuations of neutral hydrogen 21‐cm lines from the epoch of reionization (EoR) is expected to be a powerful tool for revealing the reionization process. We study the 21‐cm cross‐correlation with cosmic microwave background (CMB) temperature anisotropies, focusing on the effect of the patchy reionization. We calculate, up to second order, the angular power spectrum of the cross‐correlation between 21‐cm fluctuations and the CMB kinetic Sunyaev–Zel’dovich effect (kSZ) from the EoR, using an analytical reionization model. We show that the kSZ and the 21‐cm fluctuations are anti‐correlated on the scale corresponding to the typical size of an ionized bubble at the observed redshift of the 21‐cm fluctuations. The amplitude of the angular power spectrum of the cross‐correlation depends on the fluctuations of the ionized fraction. Especially, in a highly inhomogeneous reionization model, the amplitude reaches the order of 100 μ K 2 at ℓ∼ 3000. We also show that second‐order terms may help in distinguishing between reionization histories.