Cataclysmic Variables in Globular Clusters

TL;DR

This review discusses the significance, expected numbers, types, and observational methods for studying cataclysmic variables in globular clusters, comparing theoretical predictions with current observations and reevaluating key assumptions.

Contribution

It provides a comprehensive overview of GC CVs, analyzing discrepancies between models and observations, and reassessing common beliefs about their characteristics.

Findings

Observed CV populations are fewer than some predictions suggest.

The incidence of magnetic CVs in GCs may not be as high as previously thought.

Dwarf novae may be more common in GCs than assumed.

Abstract

Every massive globular cluster (GC) is expected to harbour a significant population of cataclysmic variables (CVs). In this review, I first explain why GC CVs matter astrophysically, how many and what types are theoretically predicted to exist and what observational tools we can use to discover, confirm and study them. I then take a look at how theoretical predictions and observed samples actually stack up to date. In the process, I also reconsider the evidence for two widely held ideas about CVs in GCs: (i) that there must be many fewer dwarf novae than expected; (ii) that the incidence of magnetic CVs is much higher in GCs than in the Galactic field.