Low surface brightness dwarf galaxies and their globular cluster populations around the low-density environment of our closest S0 NGC3115

TL;DR

This study investigates low surface brightness dwarf galaxies and their globular cluster populations around NGC 3115, revealing their properties, distribution, and implications for galaxy formation in low-density environments.

Contribution

It provides the first detailed analysis of LSB dwarf galaxies and their GCs in a low-density environment, expanding understanding of their properties and mass estimates.

Findings

LSB dwarf candidates mostly show red colors, indicating a possible link to their distance from NGC 3115.

GC populations around these dwarfs are similar to those in Fornax LSB dwarf systems.

Estimated upper limit for the total mass of these LSB dwarfs is approximately 3.3×10^{10} solar masses.

Abstract

Understanding faint dwarf galaxies is fundamental to the development of a robust theory of galaxy formation on small scales. Since the discovery of a population of ultra diffuse galaxies (UDGs) rich in globular clusters (GCs) in Coma, an increasing number of studies on low surface brightness dwarf galaxies (LSBds) have been published in recent years. The most massive LSBds have been observed predominantly in groups and clusters, with properties displaying dependence on the environment. In this work, we use deep DECam imaging to systematically identify LSBds and their GC populations around the low-density environment of NGC 3115. We carefully analyse the structure and morphology of 24 candidates, 18 of which are reported for the first time. Most candidates exhibit red colours suggesting a connection between their colour and distance to NGC 3115. We followed up with Gemini GMOS imaging 9 LSBds to properly identify their GC populations. We derive lower limits for the number of GCs associated with each galaxy. Our analysis reveals that they occur around of the same loci of Fornax LSB dwarf GC systems. The relationship between the number of GCs and total mass provides a tool in which, by counting the GCs in these galaxies, we estimate an upper limit for the total mass of these LSB dwarfs, obtaining the mean value of $\sim 3.3\times10^{10}$ M$_{\odot}$. Our results align with expectations for dwarf-sized galaxies, particularly regarding the distribution and specific frequency of their GC systems.