Chandra Measurements of a Complete Sample of X-ray Luminous Galaxy Clusters: The Luminosity-Mass Relation

TL;DR

This study uses Chandra X-ray data to analyze a complete sample of galaxy clusters, revealing a corrected luminosity-mass relation that differs significantly from uncorrected models, impacting mass estimates.

Contribution

It introduces a method to fully account for selection biases in the luminosity-mass relation of galaxy clusters, providing more accurate measurements.

Findings

The luminosity of clusters is 2.2±0.4 times higher than average for a given mass when bias-corrected.

Mass estimates are 30% lower than the population average for a given luminosity.

Hydrostatic and $Y_{X}$-based masses are consistent regardless of cluster dynamical state.

Abstract

We present the results of work involving a statistically complete sample of 34 galaxy clusters, in the redshift range 0.15$\le$z$\le$0.3 observed with $Chandra$. We investigate the luminosity-mass ($LM$) relation for the cluster sample, with the masses obtained via a full hydrostatic mass analysis. We utilise a method to fully account for selection biases when modeling the $LM$ relation, and find that the $LM$ relation is significantly different than the relation modelled when not account for selection effects. We find that the luminosity of our clusters is 2.2$\pm$0.4 times higher (when accounting for selection effects) than the average for a given mass, its mass is 30% lower than the population average for a given luminosity. Equivalently, using the $LM$ relation measured from this sample without correcting for selection biases would lead to the underestimation by 40% of the average mass of a cluster with a given luminosity. Comparing the hydrostatic masses to mass estimates determined from the $Y_{X}$ parameter, we find that they are entirely consistent, irrespective of the dynamical state of the cluster.