Light-cone observations and cosmological models: implications for inhomogeneous models mimicking dark energy

Understand

Cosmological observables are used to construct cosmological models.

• Since cosmological observations are limited to the light cone, a fixed number of observables (even measured to arbitrary accuracy) may not uniquely determine a cosmological model without additional assumptions or considerations.
• A prescription for constructing a spherically symmetric, inhomogeneous cosmological model that exactly reproduces the luminosity-distance as a function of redshift and the light-cone mass density as a function of redshift of a $\Lambda$CDM model is employed to gain insight into how an inhomogeneous cosmological model might mimic dark energy models.