How nucleation and luminosity shape faint dwarf galaxies

Abstract

We study the intrinsic shapes of a sample of over 400 quiescent galaxies in the cores of the Virgo and Fornax clusters with luminosities $10^6\le L_g/L_{\odot }\le 10^8$. Similar to satellites of the Local Group and Centaurus A, these faint, low surface brightness cluster galaxies are best described as a family of thick ($C/A>0.5$), oblate-triaxial spheroids. However, the large sample size allows us to show that the flattening of their stellar distributions depends both on luminosity and on the presence of a nuclear star cluster. Nucleated satellites are thicker at all luminosities compared to their non-nucleated counterparts, and fainter galaxies are systematically thicker as well, regardless of nucleation. Once nucleation is accounted for, we find no evidence that the environment the satellites live in plays a relevant role in setting their three-dimensional structure. We interpret both the presence of stellar nuclei and the associated thicker shapes as the result of preferential early and rapid formation, effectively making these faint nucleated galaxies the first generation of cluster satellites.

Accepted for publication in MNRAS Letters

References in corpus (14)

• The ACS Virgo Cluster Survey. VIII. The Nuclei of Early-Type Galaxies
• The ACS Virgo Cluster Survey XV. The Formation Efficiencies of Globular Clusters in Early-Type Galaxies: The Effects of Mass and Environment
• Virgo cluster early-type dwarf galaxies with the Sloan Digital Sky Survey. III. Subpopulations: distributions, shapes, origins
• The Structure and Dynamical Evolution of the Stellar Disk of a Simulated Milky Way-Mass Galaxy
• z~2: An Epoch of Disk Assembly
• The Dragonfly Nearby Galaxies Survey. III. The Luminosity Function of the M101 Group
• Virgo cluster early-type dwarf galaxies with the Sloan Digital Sky Survey. IV. The color-magnitude relation
• How effective is harassment on infalling late-type dwarfs?
• Virgo Redux: The Masses and Stellar Content of Nuclei in Early-Type Galaxies from Multi-Band Photometry and Spectroscopy
• The SAMI Galaxy Survey: the intrinsic shape of kinematically selected galaxies
• The Next Generation Virgo Cluster Survey (NGVS). XXIV. The Red Sequence to $\sim$10${}^6$ L${}_{\odot }$ and Comparisons with Galaxy Formation Models
• The Effects of Ram-pressure Stripping and Supernova Winds on the Tidal Stirring of Disky Dwarfs: Enhanced Transformation into Dwarf Spheroidals
• The intrinsic ellipticity of dwarf spheroidal galaxies: constraints from the Andromeda system
• The shapes and alignments of the satellites of the Milky Way and Andromeda

Cited by in corpus (3)

• A spectroscopic study of MATLAS-2019 with MUSE: an ultra-diffuse galaxy with an excess of old globular clusters
• Metal-poor nuclear star clusters in two dwarf galaxies near Centaurus A suggesting formation from the in-spiraling of globular clusters
• The Fornax Deep Survey (FDS) with the VST: III. Low Surface Brightness (LSB) dwarfs and Ultra Diffuse Galaxies (UDGs) in the center of the Fornax cluster