Title: Anatomy of cosmic tidal reconstruction

Abstract

21-cm intensity surveys aim to map neutral hydrogen atoms in the universe through hyper-fine emission. Unfortunately, long-wavelength (low-wavenumber) radial modes are highly contaminated by smooth astrophysical foregrounds that are six orders of magnitude brighter than the cosmological signal. This contamination also leaks into higher radial and angular wavenumber modes and forms a foreground wedge. Cosmic tidal reconstruction aims to extract the large-scale signal from anisotropic features in the local small-scale power spectrum through non-linear tidal interactions; losing small-scale modes to foreground wedge will impair its performance. In this paper, we review tidal interaction theory and estimator construction, and derive the theoretical expressions for the reconstructed spectra. We show the reconstruction is robust against peculiar velocities. Removing low line-of-sight k modes, we demonstrate cross-correlation coefficient r is greater than 0.7 on large scales (k ≲ 0.1 h Mpc^-1) even with a cut-off value |$$k^c_{\Vert }=0.1$$|h Mpc^-1. Discarding wedge modes yields 0.3 ≲ r ≲ 0.5 and completely removes the dependency on |$$k^c_{\Vert }$$|. Our theoretical predictions agree with these numerical simulations.

Authors:

Karaçaylı, Naim Göksel  ^[1];

• Search DOE PAGES for author "Karaçaylı, Naim Göksel"
• Search DOE PAGES for ORCID "0000-0001-7336-8912"

Padmanabhan, Nikhil  ^[2]

• Search DOE PAGES for author "Padmanabhan, Nikhil"
• Search DOE PAGES for ORCID "0000-0002-2885-8602"

---

+ Show Author Affiliations

1. Department of Physics, Yale University, New Haven, CT 06511, USA
2. Department of Physics, Yale University, New Haven, CT 06511, USA, Department of Astronomy, Yale University, New Haven, CT 06511, USA

Publication Date:

Fri Apr 05 00:00:00 EDT 2019

Research Org.:

Yale Univ., New Haven, CT (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1510540

Alternate Identifier(s):

OSTI ID: 1612739

Grant/Contract Number:  

SC0017660

Resource Type:

Published Article

Journal Name:

Monthly Notices of the Royal Astronomical Society

Additional Journal Information:

Journal Name: Monthly Notices of the Royal Astronomical Society Journal Volume: 486 Journal Issue: 3; Journal ID: ISSN 0035-8711

Publisher:

Royal Astronomical Society

Country of Publication:

United Kingdom

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; Astronomy & Astrophysics; methods: data analysis; cosmology: theory; large-scale structure of Universe