Testing redshift variation of the X-ray and ultraviolet luminosity relations of quasars

Fuente: arXiv
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Autori principali: Wu, Jiayi, Liu, Yang, Yu, Hongwei, Wu, Puxun
Natura: Preprint
Pubblicazione: 2025
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author Wu, Jiayi
Liu, Yang
Yu, Hongwei
Wu, Puxun
author_facet Wu, Jiayi
Liu, Yang
Yu, Hongwei
Wu, Puxun
contents Quasars serve as important cosmological probes and constructing accurate luminosity relations for them is essential for their use in cosmology. If the coefficients of quasar's luminosity relation vary with redshift, it could introduce biases into cosmological constraints derived from quasars. In this paper, we conduct a detailed analysis of the redshift variation in the X-ray luminosity and ultraviolet (UV) luminosity ($L_\mathrm{X}$-$L_\mathrm{UV}$) relations of quasars. For the standard $L_\mathrm{X}$-$L_\mathrm{UV}$ relation, we find that the relation coefficients exhibit a strong and linear correlation with redshift, which is not attributable to the selection effect. Additionally, we examine two three-dimensional, redshift-evolving $L_\mathrm{X}$-$L_\mathrm{UV}$ relations and find that the inclusion of a redshift-dependent term does not eliminate the impact of redshift evolution, as the relation coefficients continue to evolve with redshift. Finally, we construct a new $L_\mathrm{X}$-$L_\mathrm{UV}$ relation in which the redshift evolution of the relation coefficients is nearly eliminated. Calibrating the luminosity relations using Hubble parameter measurements, we demonstrate that quasars utilizing our new relation yield effective constraints on cosmological parameters that are consistent with results from Planck CMB data, unlike constraints derived from the standard relation.
format Preprint
id arxiv_https___arxiv_org_abs_2504_10862
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Testing redshift variation of the X-ray and ultraviolet luminosity relations of quasars
Wu, Jiayi
Liu, Yang
Yu, Hongwei
Wu, Puxun
Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
Quasars serve as important cosmological probes and constructing accurate luminosity relations for them is essential for their use in cosmology. If the coefficients of quasar's luminosity relation vary with redshift, it could introduce biases into cosmological constraints derived from quasars. In this paper, we conduct a detailed analysis of the redshift variation in the X-ray luminosity and ultraviolet (UV) luminosity ($L_\mathrm{X}$-$L_\mathrm{UV}$) relations of quasars. For the standard $L_\mathrm{X}$-$L_\mathrm{UV}$ relation, we find that the relation coefficients exhibit a strong and linear correlation with redshift, which is not attributable to the selection effect. Additionally, we examine two three-dimensional, redshift-evolving $L_\mathrm{X}$-$L_\mathrm{UV}$ relations and find that the inclusion of a redshift-dependent term does not eliminate the impact of redshift evolution, as the relation coefficients continue to evolve with redshift. Finally, we construct a new $L_\mathrm{X}$-$L_\mathrm{UV}$ relation in which the redshift evolution of the relation coefficients is nearly eliminated. Calibrating the luminosity relations using Hubble parameter measurements, we demonstrate that quasars utilizing our new relation yield effective constraints on cosmological parameters that are consistent with results from Planck CMB data, unlike constraints derived from the standard relation.
title Testing redshift variation of the X-ray and ultraviolet luminosity relations of quasars
topic Cosmology and Nongalactic Astrophysics
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2504.10862