Primordial Non-Gaussianity and Reionization

Abstract

The statistical properties of the primordial perturbations contain clues about the origins of those fluctuations. Although the Planck collaboration has recently obtained tight constraints on primordial non-gaussianity from cosmic microwave background measurements, it is still worthwhile to mine upcoming data sets in effort to place independent or competitive limits. The ionized bubbles that formed at redshift z~6-20 during the Epoch of Reionization are seeded by primordial overdensities, and so the statistics of the ionization field at high redshift are related to the statistics of the primordial field. Here we model the effect of primordial non-gaussianity on the reionization field. The epoch and duration of reionization are affected as are the sizes of the ionized bubbles, but these changes are degenerate with variations in the properties of the ionizing sources and the surrounding intergalactic medium. A more promising signature is the power spectrum of the spatial fluctuations in the ionization field, which may be probed by upcoming 21 cm surveys. This has the expected 1/k^2 dependence on large scales, characteristic of a biased tracer of the matter field. We project how well upcoming 21 cm observations will be able to disentangle this signal from foreground contamination. Although foreground cleaning inevitably removes the large-scale modes most impacted by primordial non-gaussianity, we find that primordial non-gaussianity can be separated from foreground contamination for a narrow range of length scales. In principle, futuristic redshifted 21 cm surveys may allow constraints competitive with Planck.

18 pages, 11 figures

References in corpus (14)

• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• The imprints of primordial non-gaussianities on large-scale structure: scale dependent bias and abundance of virialized objects
• Studying Reionization with Ly-alpha Emitters
• Keeping the Universe ionised: Photo-heating and the clumping factor of the high-redshift intergalactic medium
• Optimal limits on f_{NL}^{local} from WMAP 5-year data
• A Method for 21cm Power Spectrum Estimation in the Presence of Foregrounds
• Detecting the Rise and Fall of 21 cm Fluctuations with the Murchison Widefield Array
• 21-cm Background Anisotropies Can Discern Primordial Non-Gaussianity
• Higher Order Contributions to the 21 cm Power Spectrum
• Scale-dependent bias from primordial non-Gaussianity in general relativity
• The Pursuit of Non-Gaussian Fluctuations in the Cosmic Microwave Background
• Excursion Set Theory for generic moving barriers and non-Gaussian initial conditions
• Non-Gaussianity and Excursion Set Theory: Halo Bias
• The scale-dependent signature of primordial non-Gaussianity in the large-scale structure of cosmic reionization

Cited by in corpus (17)

• Constraints on primordial non-Gaussianity from 800,000 photometric quasars
• Cosmology on Ultralarge Scales with Intensity Mapping of the Neutral Hydrogen 21 cm Emission: Limits on Primordial Non-Gaussianity
• Inflation and Early Dark Energy with a Stage II Hydrogen Intensity Mapping Experiment
• The Hunt for Primordial Interactions in the Large Scale Structures of the Universe
• The observable 21cm signal from reionization may be perturbative
• Perturbative Reheating After Multiple-Field Inflation: The Impact on Primordial Observables
• The degeneracy between primordial non-Gaussianity and foregrounds in 21cm intensity mapping experiments
• Primordial Non-Gaussianity Estimation using 21 cm Tomography from the Epoch of Reionization
• The excursion set approach in non-Gaussian random fields
• On the Trispectrum of Galileon Inflation
• Power Spectrum and Non-Gaussianities in Anisotropic Inflation
• Testing the scale-dependent hemispherical asymmetry with the 21-cm power spectrum from the epoch of reionization
• Matrix Formalism of Excursion Set Theory: A new approach to statistics of dark matter halo counting
• Imprint of primordial non-Gaussianity on dark matter halo profiles
• The Trispectrum in the Effective Theory of Inflation with Galilean symmetry
• Star Formation for Predictive Primordial Galaxy Formation
• 21-cm power spectrum and ionization bias as a probe of long-mode modulated non Gaussian sky