TY - JOUR

T1 - Structure formation in an anisotropic universe

T2 - Eulerian perturbation theory

AU - Almeida, Juan P.Beltrán

AU - Motoa-Manzano, Josué

AU - Noreña, Jorge

AU - Pereira, Thiago S.

AU - Valenzuela-Toledo, César A.

N1 - Funding Information:
JPBA and CAVT acknowledge partial financial support from the Patrimonio Aut?nomo ? Fondo Nacional de Financiamiento para la Ciencia, la Tecnolog?a y la Innovaci?n Francisco Jos? de Caldas (MINCIENCIAS ? COLOMBIA) Grant No. 110685269447 RC-80740-465-2020, project 69723. JM acknowledges financial support from Ministerio de Ciencia, Tecnolog?a e Innovaci?n ? Colombia. JN is supported by FONDECYT grant 1211545, ?Measuring the Field Spectrum of the Early Universe?. TSP is supported by Brazilian funding agencies CAPES (Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior) and CNPq (Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico), Grants No. 438689/2018-6 and 311527/2018-3.
Publisher Copyright:
© 2022 IOP Publishing Ltd and Sissa Medialab.

PY - 2022/2

Y1 - 2022/2

N2 - We present an effective Eulerian description, in the non-relativistic regime, of the growth of cosmological perturbations around a homogeneous but anisotropic Bianchi I spacetime background. We assume a small deviation from isotropy, sourced at late times for example by dark energy anisotropic stress. We thus derive an analytic solution for the linear dark matter density contrast, and use it in a formal perturbative approach which allows us to derive a second order (non-linear) solution. As an application of the procedure followed here we derive analytic expressions for the power spectrum and the bispectrum of the dark matter density contrast. The power spectrum receives a quadrupolar correction as expected, and the bispectrum receives several angle-dependent corrections. Quite generally, we find that the contribution of a late-time phase of anisotropic expansion to the growth of structure peaks at a finite redshift between CMB decoupling and today, tough the exact redshift value is model-dependent.

AB - We present an effective Eulerian description, in the non-relativistic regime, of the growth of cosmological perturbations around a homogeneous but anisotropic Bianchi I spacetime background. We assume a small deviation from isotropy, sourced at late times for example by dark energy anisotropic stress. We thus derive an analytic solution for the linear dark matter density contrast, and use it in a formal perturbative approach which allows us to derive a second order (non-linear) solution. As an application of the procedure followed here we derive analytic expressions for the power spectrum and the bispectrum of the dark matter density contrast. The power spectrum receives a quadrupolar correction as expected, and the bispectrum receives several angle-dependent corrections. Quite generally, we find that the contribution of a late-time phase of anisotropic expansion to the growth of structure peaks at a finite redshift between CMB decoupling and today, tough the exact redshift value is model-dependent.

KW - Cosmological perturbation theory in GR and beyond

KW - dark energy theory

KW - power spectrum

UR - http://www.scopus.com/inward/record.url?scp=85126151501&partnerID=8YFLogxK

U2 - 10.1088/1475-7516/2022/02/018

DO - 10.1088/1475-7516/2022/02/018

M3 - Article

AN - SCOPUS:85126151501

VL - 2022

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

SN - 1475-7516

IS - 2

M1 - 018

ER -