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Abstract
Upcoming surveys of cosmic structures will probe scales close to the cosmological horizon, which opens up new opportunities for testing the cosmological concordance model to high accuracy. In particular, constraints on the squeezed bispectrum could rule out the singlefield hypothesis during inflation. However, the squeezed bispectrum is also sensitive to dynamical effects of general relativity as well as interactions of matter with residual radiation from the early Universe. In this paper, we present a relativistic simulation pipeline that includes these relativistic effects consistently. We produce light cones and calculate the observed number counts of cold dark matter for five redshift bins between $z=0.55$$2.25$. We compare the relativistic results against reference Newtonian simulations by means of angular power and bispectra. We find that the dynamical relativistic effects scale roughly inversely proportional to the multipole in the angular power spectrum, with a maximum amplitude of $10\%$ for $\ell \lesssim 5$. By using a smoothing method applied to the binned bispectrum we detect the Newtonian bispectrum with very high significance. The purely relativistic part of the matter bispectrum is detected with a significance of $\sim 3\,\sigma$, mostly limited by cosmic variance. We find that the pure dynamical relativistic effects accounts for up to $3\%$ and $10\%$ of the total amplitude, respectively in the squeezed and equilateral limits. Our relativistic pipeline for modelling ultralarge scales yields gaugeindependent results as we compute observables consistently on the past light cone, while the Newtonian treatment employs approximations that leave some residual gauge dependence. A gaugeinvariant approach is required in order to meet the expected level of precision of forthcoming probes of cosmic structures on ultralarge scales.
Originalsprache  Englisch 

Aufsatznummer  043 
Seitenumfang  42 
Fachzeitschrift  Journal of Cosmology and Astroparticle Physics (JCAP) 
Jahrgang  2023 
Ausgabenummer  8 
DOIs  
Publikationsstatus  Veröffentlicht  18 Aug. 2023 
ÖFOS 2012
 103044 Kosmologie
 103043 Computational Physics
Projekte
 1 Abgeschlossen

COSMO_SIMS: Astrophysics for the Dark Universe: Cosmological simulations in the context of dark matter and dark energy research
1/10/20 → 31/08/22
Projekt: Forschungsförderung