The Geodesic Light-Cone Coordinates, an Adapted System for Light-Signal-Based Cosmology

TL;DR

The paper introduces geodesic light-cone (GLC) coordinates, a versatile system tailored for light-based cosmological observations, facilitating calculations in inhomogeneous universes and improving analysis of distance measures, lensing, and large-scale structure effects.

Contribution

It presents the GLC coordinate system, a new framework optimized for light signal propagation in inhomogeneous cosmological models, enhancing various observational and theoretical computations.

Findings

GLC coordinates simplify calculations of distance-redshift relations.

They enable more accurate modeling of light propagation in complex geometries.

The system is applicable to weak lensing and large-scale structure analysis.

Abstract

Most of cosmological observables are light-propagated. I will present coordinates adapted to the propagation of null-like signals as observed by a geodesic observer. These "geodesic light-cone (GLC) coordinates" are general, adapted to calculations in inhomogeneous geometries, and their properties make them useful for a large spectrum of applications, from the estimation of the distance-redshift relation, the average on our past light cone, the effect of the large-scale structure on the Hubble diagram, to weak lensing calculations.