2015/09/30 by Suman Majumdar, Hannes Jensen, Garrelt Mellema +14 · 34 citations
Engineering · Physics and Astronomy · #Anisotropy #Antenna Design and Optimization #Astrophysics #Astrophysics and Cosmic Phenomena #Galaxy #LOFAR #Moment (physics) #Optics #Physics #Quadrupole #Radio Astronomy Observations and Technology #Radio telescope #Redshift #Redshift survey #Redshift-space distortions #Reionization #Spectral density #astro-ph.CO
paper · pdf · doi:10.1093/mnras/stv2812
published in Monthly Notices of the Royal Astronomical Society 456(2), 2080-2094 (Oxford University Press) · 17 pages, 12 figures, 1 table. Accepted for publication in MNRAS. Replaced to match the accepted version
arxiv created 2015/12/02 · openalex publication_date 2015/12/30 · arxiv updated 2016/01/26 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/08
The observed 21 cm signal from the epoch of reionization will be distorted along the line of sight by the peculiar velocities of matter particles. These redshift-space distortions will affect the contrast in the signal and will also make it anisotropic. This anisotropy contains information about the cross-correlation between the matter density field and the neutral hydrogen field, and could thus potentially be used to extract information about the sources of reionization. In this paper, we study a collection of simulated reionization scenarios assuming different models for the sources of reionization. We show that the 21 cm anisotropy is best measured by the quadrupole moment of the power spectrum. We find that, unless the properties of the reionization sources are extreme in some way, the quadrupole moment evolves very predictably as a function of global neutral fraction. This predictability implies that redshift-space distortions are not a very sensitive tool for distinguishing between reionization sources. However, the quadrupole moment can be used as a model-independent probe for constraining the reionization history. We show that such measurements can be done to some extent by first-generation instruments such as LOFAR, while the SKA should be able to measure the reionization history using the quadrupole moment of the power spectrum to great accuracy.