Skip to Main content Skip to Navigation
Journal articles

Cosmological signatures of tilted isocurvature perturbations: reionization and 21cm fluctuations

Abstract : We investigate cosmological signatures of uncorrelated isocurvature perturbations whose power spectrum is blue-tilted with spectral index 2lesssimplesssim4. Such an isocurvature power spectrum can promote early formation of small-scale structure, notably dark matter halos and galaxies, and may thereby resolve the shortage of ionizing photons suggested by observations of galaxies at high redshifts (z simeq 7-8) but that are required to reionize the universe at z ~ 10. We mainly focus on how the formation of dark matter halos can be modified. Based on the Δχ2 analysis with other cosmological parameters being fixed, we explore the connection between the spectral shape of CMB anisotropies and the reionization optical depth as a powerful probe of a highly blue-tilted isocurvature primordial power spectrum. We also study the consequences for 21cm line fluctuations due to neutral hydrogens in minihalos. Combination of measurements of the reionization optical depth and 21cm line fluctuations will provide complementary probes of a highly blue-tilted isocurvature power spectrum.
Document type :
Journal articles
Complete list of metadata

https://hal-insu.archives-ouvertes.fr/insu-03645693
Contributor : Hal Sorbonne Université Gestionnaire Connect in order to contact the contributor
Submitted on : Tuesday, April 19, 2022 - 4:16:28 PM
Last modification on : Wednesday, April 20, 2022 - 3:40:08 AM

Links full text

Identifiers

Citation

Toyokazu Sekiguchi, Hiroyuki Tashiro, Joseph Silk, Naoshi Sugiyama. Cosmological signatures of tilted isocurvature perturbations: reionization and 21cm fluctuations. JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, 2014, 2014, ⟨10.1088/1475-7516/2014/03/001⟩. ⟨insu-03645693⟩

Share

Metrics

Record views

3