# Non-parametric dark energy reconstruction using the tomographic Alcock-Paczynski test

## TL;DR

This paper introduces a non-parametric dark energy reconstruction method using the tomographic Alcock-Paczynski test combined with other observational data, revealing potential dynamical dark energy at low redshifts with improved constraints.

## Contribution

It presents a novel non-parametric approach to reconstruct dark energy's equation-of-state using the tomographic AP test, enhancing low-redshift constraints by about 50%.

## Key findings

- Favors dynamical dark energy at z<1.
- Shows a mild deviation from w=-1 at z=0.5-0.7.
- Improves low-redshift constraints by ~50%.

## Abstract

The tomographic Alcock-Paczynski (AP) method can result in tight cosmological constraints by using small and intermediate clustering scales of the large scale structure (LSS) of the galaxy distribution. By focusing on the redshift dependence, the AP distortion can be distinguished from the distortions produced by the redshift space distortions (RSD). In this work, we combine the tomographic AP method with other recent observational datasets of SNIa+BAO+CMB+$H_0$ to reconstruct the dark energy equation-of-state $w$ in a non-parametric form. The result favors a dynamical DE at $z\lesssim1$, and shows a mild deviation ($\lesssim2\sigma$) from $w=-1$ at $z=0.5-0.7$. We find the addition of the AP method improves the low redshift ($z\lesssim0.7$) constraint by $\sim50\%$.