Open AccessProbing primordial magnetic fields with the 21‐cm fluctuations
Author(s) -
Tashiro Hiroyuki,
Sugiyama Naoshi
Publication year - 2006
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.1365-2966.2006.10901.x
Subject(s) - physics , astrophysics , cosmic microwave background , magnetic field , amplitude , primordial fluctuations , brightness , galaxy , astronomy , quantum mechanics , anisotropy
Primordial magnetic fields possibly generated in the very early Universe are one of the candidates for the origin of magnetic fields observed in many galaxies and galaxy clusters. After recombination, the dissipation process of the primordial magnetic fields increases the baryon temperature. The Lorentz force acts on the residual ions and electrons to generate density fluctuations. These effects are imprinted on the cosmic microwave background (CMB) brightness temperature fluctuations produced by the neutral hydrogen 21‐cm line. We calculate the angular power spectrum of brightness temperature fluctuations for the model with the primordial magnetic fields of a several nG strength and a power‐law spectrum. It is found that the overall amplitude and the shape of the brightness temperature fluctuations depend on the strength and the spectral index of the primordial magnetic fields. Therefore, it is expected that the observations of the CMB brightness temperature fluctuations give us a strong constraint on the primordial magnetic fields.