Dynamical friction in globular cluster-rich ultra-diffuse galaxies: the case of NGC5846-UDG1

TL;DR

This paper investigates the distribution of globular clusters in the ultra-diffuse galaxy NGC5846-UDG1, using analytic and numerical methods to suggest the galaxy resides in a massive dark matter halo, demonstrating the utility of GCs as dynamical tracers.

Contribution

The study combines analytic calculations and simulations to explain GC distribution via dynamical friction, supporting the galaxy's dark matter halo presence.

Findings

GC distribution suggests mass segregation due to dynamical friction

Analytic and simulation results explain observed GC patterns

Supports the galaxy residing in a massive dark matter halo

Abstract

Ultra-diffuse galaxies that contain a large sample of globular clusters (GCs) offer an opportunity to test the predictions of galactic dynamics theory. NGC5846-UDG1 is an excellent example, with a high-quality sample of dozens of GC candidates. We show that the observed distribution of GCs in NGC5846-UDG1 is suggestive of mass segregation induced by gravitational dynamical friction. We present simple analytic calculations, backed by a series of numerical simulations, that naturally explain the observed present-day pattern of GC masses and radial positions. Subject to some assumptions on the GC population at birth, the analysis supports the possibility that NGC5846-UDG1 resides in a massive dark matter halo. This is an example for the use of GC-rich systems as dynamical (in addition to kinematical) tracers of dark matter.