Reaching small scales with low-frequency imaging: applications to the Dark Ages

Morabito, L.K.; Silk, J.

Abstract

The initial conditions for the density perturbations in the early Universe, which dictate the large-scale structure and distribution of galaxies we see today, are set during inflation. Measurements of primordial non-Gaussianity are crucial for distinguishing between different inflationary models. Current measurements of the matter power spectrum from the cosmic microwave background only constrain this on scales up to k ∼ 0.1 Mpc−1. Reaching smaller angular scales (higher values of k) can provide new constraints on non-Gaussianity. A powerful way to do this is by measuring the HI matter power spectrum at z≳30. In this paper, we investigate what values of k can be reached for the Low-Frequency Array (LOFAR), which can achieve ≲1″ resolution at approximately 50 MHz. Combining this with a technique to isolate the spectrally smooth foregrounds to a wedge in k∥–k⊥ space, we demonstrate what values of k we can feasibly reach within observational constraints. We find that LOFAR is approximately five orders of magnitude away from the desired sensitivity, for 10 years of integration time.

Citation

Morabito, L., & Silk, J. (2021). Reaching small scales with low-frequency imaging: applications to the Dark Ages. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 379(2188), Article 20190571. https://doi.org/10.1098/rsta.2019.0571

• Journal Article Type: Article
• Acceptance Date: Jul 1, 2020
• Online Publication Date: Nov 23, 2020
• Publication Date: 2021-01
• Deposit Date: Jan 11, 2021
• Publicly Available Date: Jan 13, 2021
• Journal: Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences.
• Print ISSN: 1364-503X
• Electronic ISSN: 1471-2962
• Publisher: The Royal Society
• Peer Reviewed: Peer Reviewed
• Volume: 379
• Issue: 2188
• Article Number: 20190571
• DOI: https://doi.org/10.1098/rsta.2019.0571
• Public URL: https://durham-repository.worktribe.com/output/1253705
• Related Public URLs: https://arxiv.org/abs/2007.13353