Probing Intracluster Dynamics and Evolution of Globular Clusters through Cataclysmic Variable Populations

TL;DR

This study combines simulations and observations to show that the X-ray luminosity of cataclysmic variables in globular clusters correlates with the clusters' dynamical evolution, revealing how cluster dynamics influence binary star properties.

Contribution

It introduces a combined simulation and observational approach to link globular cluster dynamical stages with CV X-ray properties, highlighting CVs as tracers of cluster evolution.

Findings

CVs in more evolved clusters are brighter in X-ray emission.

Significant differences in CV X-ray luminosity distributions among different cluster dynamical stages.

Both simulations and observations support the correlation between cluster dynamical state and CV properties.

Abstract

Dynamical interactions in globular clusters (GCs) significantly impact the formation and evolution of binary sources, including cataclysmic variables (CVs). This study investigates the connection between dynamical states of GCs and X-ray luminosity ($L_{x}$) distributions of CV populations through both simulations and actual observations. Utilizing a Monte Carlo simulation tool, MOCCA, we categorize the simulated GCs into three different evolutionary stages which are referred to as Classes I/II/III. Significant differences are found in the $L_{x}$ distributions of the CVs among these three Classes. In observational aspects, we have analyzed 179 CV candidates in 18 GCs observed by the {\it Chandra} X-ray Observatory. By dividing these GCs into three Families of different dynamical ages, namely Families I/II/III, the $L_{x}$ distributions of the CV candidates also show significant differences among these three Families. Both simulations and observational results suggest that CVs in more dynamically evolved clusters (Class/Family III) exhibit brighter X-ray emission. This highlights the influence of the dynamical status of a GC on the properties of its hosted compact binaries. Similar to blue stragglers, CV populations can serve as tracers of a GC's dynamical history. Our findings provide insights for understanding the interplay between intracluster dynamics and the evolution of compact binaries in GCs.