Probing Small Scale Primordial Power Spectrum with 21cm Line Global Signal

Abstract

We argue that the global signal of neutral hydrogen 21cm line can be a powerful probe of primordial power spectrum on small scales. Since the amplitude of small scale primordial fluctuations is important to determine the early structure formation and the timing when the sources of Lyman $\alpha$ photons are produced, they in turn affect the neutral hydrogen 21cm line signal. We show that the information of the position of the absorption trough can severely constrain the small scale amplitude of primordial fluctuations once astrophysical parameters relevant to the 21cm line signal are fixed. We also discuss how the uncertainties of astrophysical parameters affect the constraints.

21 pages, 8 figures, one column, accepted for publication in PRD

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Cited by in corpus (14)

• The CosmoVerse White Paper: Addressing observational tensions in cosmology with systematics and fundamental physics
• Probing the Small-Scale Matter Power Spectrum with Large-Scale 21-cm Data
• ETHOS -- An Effective Theory of Structure Formation: Impact of Dark Acoustic Oscillations on Cosmic Dawn
• Constraining Warm Dark Matter and Pop III stars with the Global 21-cm Signal
• Constraints on Primordial Power Spectrum from Galaxy Luminosity Functions
• Small-scale primordial fluctuations in the 21cm Dark Ages signal
• Probing the primordial Universe with 21-cm line from cosmic dawn/epoch of reionization
• Impact of the primordial fluctuation power spectrum on the reionization history
• Probing isocurvature perturbations with 21-cm global signal in the light of HERA result
• Escape from the swamp with spectator
• Global 21 cm signal: a promising probe of primordial features
• Particle production during inflation: constraints expected from redshifted 21 cm observations from the epoch of reionization
• Updated constraints on the primordial power spectrum at sub-Mpc scales
• Influence of the deviation of the matter power spectrum at small scales on the global 21-cm signal at cosmic dawn