The Hubble diagram of high redshift objects, QSOs and AGNs

TL;DR

This study investigates the Hubble diagram of high redshift objects like QSOs and AGNs, revealing a flattening at z≥3, which could provide new insights into cosmological parameters despite current data limitations.

Contribution

The paper presents the first analysis of the Hubble diagram for QSOs and AGNs at high redshift, highlighting a potential flattening that challenges standard cosmological models.

Findings

Hubble diagram flattens for z≥3

High redshift objects show anomalies in brightness and metallicity

Results suggest new constraints on cosmological parameters

Abstract

According to the Hubble law, high redshift objects such as Quasar (QSOs), X-ray Active Galactic Nuclei (AGN) together with the Gamma Ray Burst (GRBs) are the fastest and farthest objects. These characteristics provides strong motivations for they to be used to constrain the cosmological parameters, without the limitations found in the Ia supernovae study and which is restricted to redshift of up to 1.7. However, the variability and behavior in the QSOs and AGNs spectra tell us that they have very complex structures and the standard candle framework can not be applied. So far the available data of QSOs and AGNs have shown some anomalies observed in their brightness and metallicities, difficult to understand, under an orthodox point of view. Here, we show that their Hubble diagram flattens for $z\geq 3 $. The result need further confirmation, because the statistics of high redshift extragalactic objects is still poor. Details and some implications of these results are reported in this work.