Global 21 cm signal: a promising probe of primordial features

Abstract

Inflationary models that involve bursts of particle production generate bump-like features in the primordial power spectrum of density perturbations. These features influence the evolution of density fluctuations, leaving their unique signatures in cosmological observations. A detailed investigation of such signatures would help constrain physical processes during inflation. With this motivation, the goal of this paper is two-fold. First, we conduct a detailed analysis of the effects of bump-like primordial features on the sky-averaged 21 cm signal. Using semi-numerical simulations, we demonstrate that the primordial features can significantly alter the ionization history and the global 21 cm profile, making them a promising probe of inflationary models. We found a special scale (namely, the turnover wavenumber, $k^{\mathrm{turn}}$) at which the effect of primordial bump-like features on the global 21 cm profile vanishes. Also, we found that the behaviour of the primordial features on the global profile and ionization history are quite opposite for $k>k^{\mathrm{turn}}$ and $k<k^{\mathrm{turn}}$. We trace the root cause of these behaviours to the effects of primordial features on the halo mass function at high redshifts. Furthermore, we discuss the degeneracy between the astrophysical parameters and the primordial features in detail. Secondly, for a fixed set of astrophysical parameters, we derive upper limits on the amplitude of bump-like features in the range $10^{-1}<k[{\mathrm{Mpc}}^{-1}]<10^2$ using current limits on optical depth to reionization from CMB data by Planck.

31 pages, minor revisions made. The updated draft matches the published version in JCAP

References in corpus (27)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Model-independent evidence in favor of an end to reionization by z~6
• Inferences on the Timeline of Reionization at z~8 From the KMOS Lens-Amplified Spectroscopic Survey
• Constraining the neutral fraction of hydrogen in the IGM at redshift 7.5
• 21cmFAST v3: A Python-integrated C code forgenerating 3D realizations of the cosmic 21cm signal
• Texas Spectroscopic Search for Ly$\alpha$ Emission at the End of Reionization III. the Ly$\alpha$ Equivalent-width Distribution and Ionized Structures at $z>7$
• BIGHORNS - Broadband Instrument for Global HydrOgen ReioNisation Signal
• Early results from GLASS-JWST. XIV: A spectroscopically confirmed protocluster 650 million years after the Big Bang
• Toward Empirical Constraints on the Global Redshifted 21 cm Brightness Temperature During the Epoch of Reionization
• Cosmological Fluctuations from Infra-Red Cascading During Inflation
• Long Dark Gaps in the Ly$\beta$ Forest at $z<6$: Evidence of Ultra Late Reionization from XQR-30 Spectra
• (Nearly) Model-Independent Constraints on the Neutral Hydrogen Fraction in the Intergalactic Medium at $z\sim 5-7$ Using Dark Pixel Fractions in Ly$\alpha$ and Ly$\beta$ Forests
• The Evolution of the Lyman-Alpha Luminosity Function During Reionization
• Inferring the IGM Neutral Fraction at z ~ 6-8 with Low-Luminosity Lyman Break Galaxies
• LAGER Ly$\alpha$ Luminosity Function at $z\sim 7$, Implications for Reionization
• Damping Wing-Like Features in the Stacked Ly$\alpha$ Forest: Potential Neutral Hydrogen Islands at $z<6$
• Mapper of the IGM spin temperature: instrument overview
• Damping wings in the Lyman-α forest: a model-independent measurement of the neutral fraction at 5.4<z<6.1
• The Universe is at Most 88% Neutral at z=10.6
• PRATUSH experiment concept and design overview
• Observing nulling of primordial correlations via the 21 cm signal
• New constraints on primordial features from the galaxy two-point correlation function
• Investigating ionospheric calibration for LOFAR 2.0 with simulated observations
• A Bump in the Blue Axion Isocurvature Spectrum
• Large Field Excursions from Dimensional (De)construction
• Extra-Natural Inflation (De)constructed
• Particle production during inflation: constraints expected from redshifted 21 cm observations from the epoch of reionization

Cited by in corpus (2)

• A Bayesian approach to modelling spectrometer data chromaticity corrected using beam factors -- II. Model priors and posterior odds
• Absorption in the 21 cm Hydrogen Line at $z>10$ as a Sensitive Tool for the Construction of a Cosmological Model on Small Scales