Title: Cosmological cross-correlations and nearest neighbour distributions

Abstract

Cross-correlations between data sets are used in many different contexts in cosmological analyses. Recently, k-nearest neighbour cumulative distribution functions (kNN-CDF) were shown to be sensitive probes of cosmological (auto) clustering. In this paper, we extend the framework of NN measurements to describe joint distributions of, and correlations between, two data sets. We describe the measurement of joint kNN-CDFs, and show that these measurements are sensitive to all possible connected N-point functions that can be defined in terms of the two data sets. We describe how the cross-correlations can be isolated by combining measurements of the joint kNN-CDFs and those measured from individual data sets. We demonstrate the application of these measurements in the context of Gaussian density fields, as well as for fully non-linear cosmological data sets. Using a Fisher analysis, we show that measurements of the halo-matter cross-correlations, as measured through NN measurements are more sensitive to the underlying cosmological parameters, compared to traditional two-point cross-correlation measurements over the same range of scales. Finally, we demonstrate how the NN cross-correlations can robustly detect cross-correlations between sparse samples – the same regime where the two-point cross-correlation measurements are dominated by noise.

Authors:

Banerjee, Arka  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-5209-1173"

Abel, Tom ^[2]

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+ Show Author Affiliations

1. Fermi National Accelerator Laboratory, Cosmic Physics Center, Batavia, IL 60510, USA, Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94305, USA, Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305, USA, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
2. Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94305, USA, Department of Physics, Stanford University, 382 Via Pueblo Mall, Stanford, CA 94305, USA, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA

Publication Date:

Thu Apr 22 00:00:00 EDT 2021

Research Org.:

Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), High Energy Physics (HEP)

OSTI Identifier:

1781444

Alternate Identifier(s):

OSTI ID: 1779478; OSTI ID: 1818470

Report Number(s):

FERMILAB-PUB-21-029-T; arXiv:2102.01184
Journal ID: ISSN 0035-8711

Grant/Contract Number:  

AC02-76SF00515; AC02-07CH11359

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: 504 Journal Issue: 2; Journal ID: ISSN 0035-8711

Publisher:

Oxford University Press

Country of Publication:

United Kingdom

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; cosmology; large-scale structure of the Universe