A possible signature of the influence of tidal perturbations in dwarf galaxy scaling relations

Abstract

Dwarf galaxies are excellent cosmological probes, because their shallow potential wells make them very sensitive to the key processes that drive galaxy evolution, including baryonic feedback, tidal interactions, and ram pressure stripping. However, some of the key parameters of dwarf galaxies, which help trace the effects of these processes, are still debated, including the relationship between their sizes and masses. We re-examine the Fornax Cluster dwarf population from the point of view of isomass-radius--stellar mass relations (IRSMRs) using the Fornax Deep Survey Dwarf galaxy Catalogue, with the centrally located (among dwarfs) $3.63{\mathcal{M}}_{\odot }$~pc${}^{-2}$ isodensity radius defining our fiducial relation. This relation is a powerful diagnostic tool for identifying dwarfs with unusual structure, as dwarf galaxies' remarkable monotonicity in light profile shapes, as a function of stellar mass, reduces the relation's scatter tremendously. By examining how different dwarf properties (colour, tenth-nearest-neighbour distance, etc.) correlate with distance from our fiducial relation, we find a significant population of structural outliers with comparatively lower central mass surface density and larger half-light-radii, residing in locally denser regions in the cluster, albeit with similar red colours. We propose that these faint, extended outliers likely formed through tidal disturbances, which make the dwarfs more diffuse, but with little mass loss. Comparing these outliers with ultra-diffuse galaxies (UDGs), we find that the term UDG lacks discriminatory power; UDGs in the Fornax Cluster lie both on and off of IRSMRs defined at small radii, while IRSMR outliers with masses below $\sim 10^{7.5}{\mathcal{M}}_{\odot }$ are excluded from the UDG classification due to their small effective radii.

16 pages (+2 appendix), 10 figures, accepted for publication in MNRAS

References in corpus (43)

• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• Mass, Metal, and Energy Feedback in Cosmological Simulations
• Structure and star formation in galaxies out to z=3: evidence for surface density dependent evolution and upsizing
• The Tidal Evolution of Local Group Dwarf Spheroidals
• NIHAO XI: Formation of Ultra-Diffuse Galaxies by outflows
• A Revised Model for the Formation of Disk Galaxies: Low Spin and Dark-Halo Expansion
• Scaling Relations of Spiral Galaxies
• Introducing the NewHorizon simulation: Galaxy properties with resolved internal dynamics across cosmic time
• On the galaxy stellar mass function, the mass-metallicity relation, and the implied baryonic mass function
• Virgo cluster early-type dwarf galaxies with the Sloan Digital Sky Survey. III. Subpopulations: distributions, shapes, origins
• Virgo cluster early-type dwarf galaxies with the Sloan Digital Sky Survey. II. Early-type dwarfs with central star formation
• The formation and evolution of low-surface-brightness galaxies
• The Dependence of Galaxy Morphology and Structure on Environment and Stellar Mass
• A physically motivated definition for the size of galaxies in an era of ultra-deep imaging
• Revised Filter Profiles and Zero Points for Broadband Photometry
• The Fornax Deep Survey (FDS) with VST. VI. Optical properties of the dwarf galaxies in the Fornax cluster
• Census and classification of low-surface-brightness structures in nearby early-type galaxies from the MATLAS survey
• Photometric properties of Local Volume dwarf galaxies
• The early-type dwarf galaxy population of the Centaurus cluster
• Galaxy And Mass Assembly (GAMA): The dependence of the galaxy luminosity function on environment, redshift and colour
• The Next Generation Virgo Cluster Survey. XII. Stellar Populations and Kinematics of Compact, Low-Mass Early-Type Galaxies from Gemini GMOS-IFU Spectroscopy
• The origin of low-surface-brightness galaxies in the dwarf regime
• The distribution and morphologies of Fornax Cluster dwarf galaxies suggest they lack dark matter
• The Fornax Deep Survey (FDS) with the VST XI. The search for signs of preprocessing between the Fornax main cluster and Fornax A group
• The cumulative star-formation histories of dwarf galaxies with TNG50. I: Environment-driven diversity and connection to quenching
• Radio AGN in nearby dwarf galaxies: the important role of AGN in dwarf-galaxy evolution
• Newly discovered dwarf galaxies in the MATLAS low density fields
• Hubble Space Telescope Survey of the Perseus Cluster: II. Photometric scaling relations in different environments
• Redistribution of Stars and Gas in the Star Formation Deserts of Barred Galaxies
• The edges of galaxies: Tracing the limits of star formation
• The Fornax Deep Survey with VST. X. The assembly history of the bright galaxies and intra-group light in the Fornax A subgroup
• Are ultra-diffuse galaxies Milky Way-sized?
• The Spectroscopy and H-band Imaging of Virgo cluster galaxies (SHIVir) Survey: Scaling Relations and the Stellar-to-Total Mass Relation
• $R_{\mathrm{e}}$. I. Understanding galaxy sizes, associated luminosity densities, and the artificial division of the early-type galaxy population
• Disk Galaxy Scaling Relations in the SFI++: Intrinsic Scatter and Applications
• Stellar masses, sizes, and radial profiles for 465 nearby early-type galaxies: an extension to the Spitzer Survey of Stellar Structure in Galaxies (S${}^4$G)
• VIS3COS: II. Nature and nurture in galaxy structure and morphology
• Young, metal-enriched cores in early-type dwarf galaxies in the Virgo cluster based on colour gradients
• How similar is the stellar structure of low-mass late-type galaxies to that of early-type dwarfs?
• Analysis of the galaxy size versus stellar mass relation
• A MegaCam Survey of Outer Halo Satellites. VII. A Single Sérsic Index v/s Effective Radius Relation for Milky Way Outer Halo Satellites
• Geometrical tests of cosmological models. II. Calibration of rotational widths and disc scaling relations
• Structural analysis of massive galaxies using HST deep imaging at z < 0.5

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• The MeerKAT Fornax Survey II. The rapid removal of HI from dwarf galaxies in the Fornax cluster
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• The structural properties of nearby dwarf galaxies in low density environments -- size, surface brightness and colour gradients
• Cosmic reflections I: the structural diversity of simulated and observed low-mass galaxy analogues
• Nearby dwarf galaxies with extreme star formation rates: a window into dwarf-galaxy evolution in the early Universe