Quasars: Standard Candles up to z = 7.5 with the Precision of Supernovae Ia

Abstract

Currently, the Λ cold dark matter model, which relies on the existence of cold dark matter and a cosmological constant Λ, best describes the universe. However, we lack information in the high-redshift (z) region between Type Ia supernovae (SNe Ia; up to z = 2.26) and the cosmic microwave background (z = 1100), an interval crucial to test cosmological models and their possible evolution. We have defined a sample of 983 quasars up to z = 7.54 with a reduced intrinsic dispersion δ = 0.007, which determines the matter density parameter Ω M with the same precision of SNe Ia. Although previous analysis have used quasars as cosmological tools, this is the first time that high-redshift sources, in this case quasars, as standalone cosmological probes yield such tight constraints on Ω M . Our results show the importance of correcting cosmological relationships for selection biases and redshift evolution and how the choice of a golden sample reduces considerably the intrinsic scatter. This proves the reliability of quasars as standard cosmological candles.

The Scavenger Hunt for Quasar Samples to Be Used as Cosmological Tools

“…This relation within each bin allows us to highlight which QSO sources should be removed. Moreover, we have detailed in Section 5 that our analysis with the binning gives compatible results with the unbinned data (see [59] for comparison). We also further investigate different choices for the division into bins of the initial sample in Sections 3.1.2-3.1.4 and their impact on the cosmological results in Appendix A.…”

A Critical Discussion on the H0 Tension

“…Other promising high-redshift indicators are Quasars [212]. For these objects, empirical correlations among physical parameters have been found, so, as in the case of GRBs, they could constitute a formidable and populated set of objects to test the Universe at high redshift [213][214][215][216][217][218].…”

Reducing the Uncertainty on the Hubble Constant up to 35% with an Improved Statistical Analysis: Different Best-fit Likelihoods for Type Ia Supernovae, Baryon Acoustic Oscillations, Quasars, and Gamma-Ray Bursts

“…The QSO community has been striving to finetune and choose sources to be suitable for cosmological studies by carefully removing as much as possible observational biases, as described in Risaliti & Lusso (2015, Lusso & Risaliti (2016), Salvestrini et al (2019), andLusso et al (2020). As in Dainotti et al (2022a), Lenart et al (2023), Bargiacchi et al (2023), and Dainotti et al (2023a), we use this final cleaned sample, but without imposing any cut in redshift, such as the one at z = 0.7 investigated in Lusso et al (2020), to avoid introducing additional truncation and that the sample is biased against high-redshift sources only.…”

“…It has already been employed for GRBs (Dainotti et al 2013a(Dainotti et al , 2015(Dainotti et al , 2017b(Dainotti et al , 2021a(Dainotti et al , 2023b and QSOs (Dainotti et al 2022a;Bargiacchi et al 2023;Lenart et al 2023). Here we apply this method by using the results obtained by Dainotti et al (2023b) for GRBs and by Dainotti et al (2022a) and Lenart et al (2023) for QSOs, as already detailed in Bargiacchi et al (2023) and Dainotti et al (2023a).…”