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Article
Report number	arXiv:1908.00527
Title	Anisotropies and non-Gaussianity of the Cosmological Gravitational Wave Background
Author(s)	Bartolo, N. (U. Padua, Dept. Phys. Astron. ; INFN, Padua ; Padua U. ; Padua Observ.) ; Bertacca, D. (U. Padua, Dept. Phys. Astron. ; INFN, Padua ; Padua U., Astron. Dept.) ; Matarrese, S. (U. Padua, Dept. Phys. Astron. ; GSSI, Aquila ; INFN, Padua ; Padua U.) ; Peloso, M. (INFN, Padua ; U. Padua, Dept. Phys. Astron.) ; Ricciardone, A. (INFN, Padua) ; Riotto, A. (CERN ; Geneva U., CAP) ; Tasinato, G. (Swansea U.)
Publication	2019-12-04
Imprint	2019-08-01
Number of pages	7
Note	5 pages, 1 figure
In:	Phys. Rev. D 100 (2019) 121501
DOI	10.1103/PhysRevD.100.121501
Subject category	hep-th ; Particle Physics - Theory ; hep-ph ; Particle Physics - Phenomenology ; gr-qc ; General Relativity and Cosmology ; astro-ph.CO ; Astrophysics and Astronomy
Abstract	The Stochastic Gravitational Wave Background (SGWB) is expected to be a key observable for Gravitational Wave (GW) interferometry. Its detection will open a new window on early universe cosmology and on the astrophysics of compact objects. Using a Boltzmann approach, we study the angular anisotropies of the GW energy density, which is an important tool to disentangle the different cosmological and astrophysical contributions to the SGWB. Anisotropies in the cosmological background are imprinted both at its production, and by GW propagation through the large-scale scalar and tensor perturbations of the universe. The first contribution is not present in the Cosmic Microwave Background (CMB) radiation (as the universe is not transparent to photons before recombination), causing an order one dependence of the anisotropies on frequency. Moreover, we provide a new method to characterize the cosmological SGWB through its possible deviation from a Gaussian statistics. In particular, the SGWB will become a new probe of the primordial non-Gaussianity of the large-scale cosmological perturbations.
Copyright/License	publication: © 2019-2024 authors preprint: (License: arXiv nonexclusive-distrib 1.0) CC-BY-4.0

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