The Nature of Dark Energy from deep Cluster Abundance

TL;DR

This paper examines the challenges of using deep cluster abundance and redshift dependence to distinguish the nature of Dark Energy, highlighting the subtle differences in observational signatures between models.

Contribution

It compares the expected observational differences between flat LCDM and dynamical Dark Energy models, emphasizing the difficulty in detecting DE nature through cluster counts.

Findings

Cluster abundances in comoving volume and geometrical factors can reinforce or oppose each other.

Differences in angular densities are significant when Omega_mo varies, but small when DE nature varies.

Detecting DE nature via cluster abundance is more challenging than previously thought.

Abstract

We show that using the redshift dependence of the deep cluster abundance to detect the nature of Dark Energy is a serious challenge. We compare the expected differences between flat LCDM models, with different Omega_mo, with the difference between LCDM and dynamical DE models. In the former case, cluster abundances in comoving volume and geometrical factors act in the same direction, yielding a significant difference between the expected angular densities. On the contrary, when we keep a constant Omega_mo and change the DE nature,abundances in comoving volume and geometrical factors act in the opposite direction, so that the expected differences in angular densities reduce to small factors.