Euclid: Early Release Observations – Interplay between dwarf galaxies and their globular clusters in the Perseus galaxy cluster

UNSPECIFIED (2025) Euclid: Early Release Observations – Interplay between dwarf galaxies and their globular clusters in the Perseus galaxy cluster. Astronomy and Astrophysics, 703: A184. ISSN 1432-0746

Abstract

We present an analysis of globular clusters (GCs) of dwarf galaxies in the Perseus galaxy cluster that explores the relationship between dwarf galaxy properties and their GCs. Our focus is on GC numbers ( N GC ) and GC half-number radii ( R GC ) around dwarf galaxies, and their relations with host galaxy stellar masses ( M * ), central surface brightnesses ( μ 0 ), and effective radii ( R e ). This work is unique due to its large sample size and the absence of pre-selection based on μ 0 and R GC for dwarf galaxies. Interestingly, we find that at a given stellar mass, R GC is almost independent of the host galaxy μ 0 and R e , while R GC / R e depends on μ 0 and R e . Lower surface brightness and diffuse dwarf galaxies show R GC / R e ≈ 1, while higher surface brightness and compact dwarf galaxies show R GC / R e ≈ 1.5–2. This means that for dwarf galaxies of similar stellar mass, the GCs have a similar median extent; however, their distribution is different from the field stars of their host. Additionally, low surface brightness and diffuse dwarf galaxies on average have a higher N GC than high surface brightness and compact dwarf galaxies at any given stellar mass. We also find that ultra-diffuse galaxies (UDGs) and non-UDGs in the sample have a similar R GC , while UDGs have a smaller R GC / R e (typically less than one) and a three to four times higher N GC than non-UDGs. Furthermore, when examining nucleated versus non-nucleated dwarf galaxies, we found that for M * > 10 8 M ⊙ , nucleated dwarf galaxies seem to have a smaller R GC and R GC / R e , with no significant differences seen between their N GC except at M * < 10 8 M ⊙ , where the nucleated dwarf galaxies tend to have a higher N GC . Lastly, we explored the stellar-to-halo mass ratio (SHMR) of dwarf galaxies (halo mass based on N GC ) and conclude that the Perseus cluster dwarf galaxies follow the expected SHMR at z = 0 extrapolated down to M * = 10 6 M ⊙ .