The stellar mass - physical effective radius relation for dwarf galaxies in low-density environments

Abstract

The scaling relation between stellar mass ($M_{\ast }$) and physical effective radius ($r_e$) has been well-studied using wide spectroscopic surveys. However, these surveys suffer from severe surface brightness incompleteness in the dwarf galaxy regime, where the relation is poorly constrained. In this study, I use a Bayesian empirical model to constrain the power-law exponent $\beta$ of the $M_{\ast }$-$r_e$ relation for late-type dwarfs ($10^7$$\le$$M_{\ast }$/$M_{\odot }$$\le$$10^9$) using a sample of 188 isolated low surface brightness (LSB) galaxies, accounting for observational incompleteness. Surprisingly, the best-fitting model ($\beta$=0.40$\pm$0.07) indicates that the relation is significantly steeper than would be expected from extrapolating canonical models into the dwarf galaxy regime. Nevertheless, the best fitting $M_{\ast }$-$r_e$ relation closely follows the distribution of known dwarf galaxies. These results indicate that extrapolated canonical models over-predict the number of large dwarf (i.e. LSB) galaxies, including ultra-diffuse galaxies (UDGs), explaining why they are over-produced by some semi-analytic models. The best-fitting model also constrains the power-law exponent of the physical size distribution of UDGs to $n[\mathrm{de}{\mathrm{x}}^{-1}]\propto$$r_e^{3.54\pm 0.33}$, consistent to within 1$\sigma$ of the corresponding value in cluster environments and with the theoretical scenario in which UDGs occupy the high-spin tail of the normal dwarf galaxy population.

arXiv commentAccepted in MNRAS letters

References in corpus (30)

• emcee: The MCMC Hammer
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• The size distribution of galaxies in the Sloan Digital Sky Survey
• Semi-Analytic Modelling of Galaxy Formation: The Local Universe
• Galaxy And Mass Assembly: Stellar Mass Estimates
• Forty-Seven Milky Way-Sized, Extremely Diffuse Galaxies in the Coma Cluster
• Second Data Release of the Hyper Suprime-Cam Subaru Strategic Program
• Galaxy And Mass Assembly (GAMA): The galaxy stellar mass function at z < 0.06
• Galaxy And Mass Assembly (GAMA): mass-size relations of z$<$0.1 galaxies subdivided by Sérsic index, colour and morphology
• NIHAO XI: Formation of Ultra-Diffuse Galaxies by outflows
• Ultra-diffuse galaxies: the high-spin tail of the abundant dwarf galaxy population
• Analytical approximations of K-corrections in optical and near-infrared bands
• (Almost) Dark Galaxies in the ALFALFA Survey: Isolated HI Bearing Ultra Diffuse Galaxies
• The abundance and spatial distribution of ultra-diffuse galaxies in nearby galaxy clusters
• A distance of 13 Mpc resolves the claimed anomalies of the galaxy lacking dark matter
• Galaxy And Mass Assembly (GAMA): The galaxy stellar mass function to $z=0.1$ from the r-band selected equatorial regions
• The formation and evolution of low-surface-brightness galaxies
• A Universe of Ultra-Diffuse Galaxies: Theoretical Predictions from $\Lambda$CDM Simulations
• The abundance of ultra-diffuse galaxies from groups to clusters: UDGs are relatively more common in more massive haloes
• The Formation of Ultra-Diffuse Galaxies in the RomulusC Galaxy Cluster Simulation
• The Next Generation Virgo Cluster Survey (NGVS). XXX. Ultra-Diffuse Galaxies and their Globular Cluster Systems
• Robust HI kinematics of gas-rich ultra-diffuse galaxies: hints of a weak-feedback formation scenario
• NIHAO-UHD: The properties of MW-like stellar disks in high resolution cosmological simulations
• An EAGLE's View of Ex-situ Galaxy Growth
• The origin of low-surface-brightness galaxies in the dwarf regime
• Measuring distances to low-luminosity galaxies using surface brightness fluctuations
• The quiescent fraction of isolated low surface brightness galaxies: Observational constraints
• The contribution of HI-bearing ultra-diffuse galaxies to the cosmic number density of galaxies
• The Galaxy Stellar Mass Function and Low Surface Brightness Galaxies from Core-Collapse Supernovae
• The galaxy stellar mass function from CCSNe with improved photo-z techniques

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• The galaxy-halo size relation of low-mass galaxies in FIRE
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