EDGE: What shapes the relationship between HI and stellar observables in faint dwarf galaxies?

Abstract

We show how the interplay between feedback and mass-growth histories introduces scatter in the relationship between stellar and neutral gas properties of field faint dwarf galaxies ($M_{\star }⪅10^6{M}_{\odot }$). Across a suite of cosmological, high-resolution zoomed simulations, we find that dwarf galaxies of stellar masses $10^5\le M_{\star }\le 10^6{M}_{\odot }$ are bimodal in their cold gas content, being either HI-rich or HI-deficient. This bimodality is generated through the coupling between (i) the modulation of HI contents by the background of ultraviolet radiation (UVB) at late times and (ii) the significant scatter in the stellar-mass-halo-mass relationship induced by reionization. Furthermore, our HI-rich dwarfs exhibit disturbed and time-variable neutral gas distributions primarily due to stellar feedback. Over the last four billion years, we observe order-of-magnitude changes around the median $M_{HI}$, factor-of-a-few variations in HI spatial extents, and spatial offsets between HI and stellar components regularly exceeding the galaxies' optical sizes. Time variability introduces further scatter in the $M_{\star }-M_{HI}$ relation and affects a galaxy's detectability in HI at any given time. These effects will need to be accounted for when interpreting observations of the population of faint, HI-bearing dwarfs by the combination of optical and radio wide, deep surveys.

Matching MNRAS-accepted version after minor revisions. Results unchanged

References in corpus (22)

• Massloss of galaxies due to a UV-background
• xCOLD GASS: the complete IRAM-30m legacy survey of molecular gas for galaxy evolution studies
• COLD GASS, an IRAM legacy survey of molecular gas in massive galaxies: I. Relations between H2, HI, stellar content and structural properties
• Momentum Injection by Supernovae in the Interstellar Medium
• The stellar mass-halo mass relation of isolated field dwarfs: a critical test of $\Lambda$CDM at the edge of galaxy formation
• How to quench a galaxy
• MIGHTEE-HI: The HI emission project of the MeerKAT MIGHTEE survey
• A Catalog of Ultra-compact High Velocity Clouds from the ALFALFA Survey: Local Group Galaxy Candidates?
• Delayed Star Formation in Isolated Dwarf Galaxies: HST Star Formation History of the Aquarius Dwarf Irregular
• The properties of "dark" ΛCDM halos in the Local Group
• ALFALFA Discovery of the Nearby Gas-rich Dwarf Galaxy Leo P. V. Neutral Gas Dynamics and Kinematics
• VoIgt profile Parameter Estimation Routine (VIPER): H I photoionization rate at z<0.5
• The edge of galaxy formation I: formation and evolution of MW-satellites analogues before accretion
• Late Gas accretion onto Primordial Minihalos: a Model for Leo T, Dark Galaxies and Extragalactic High-Velocity Clouds
• Eridanus II: A Fossil from Reionization with an Off-Center Star Cluster
• Quadratic genetic modifications: a streamlined route to cosmological simulations with controlled merger history
• The Enigmatic (Almost) Dark Galaxy Coma P: Distance Measurement and Stellar Populations from HST Imaging
• Characterizing the Circumgalactic Medium of the Lowest-Mass Galaxies: A Case Study of IC 1613
• Predictions for the FAST telescope's CRAFTS Extra-Galactic HI Survey
• The Tail of Late-forming Dwarf Galaxies in $\Lambda$CDM
• Modelling H${}_2$ and its effects on star formation using a joint implementation of GADGET-3 and KROME
• Galaxy Properties at the Faint End of the HI Mass Function

Cited by in corpus (19)

• Extinguishing the FIRE: environmental quenching of satellite galaxies around Milky Way-mass hosts in simulations
• The Pandora project. I: the impact of radiation and cosmic rays on baryonic and dark matter properties of dwarf galaxies
• EDGE: The sensitivity of ultra-faint dwarfs to a metallicity-dependent initial mass function
• The cosmic UV background and the beginning and end of star formation in simulated field dwarf galaxies
• The SAMI-Fornax Dwarfs Survey III: Evolution of [$\alpha$/Fe] in dwarfs, from Galaxy Clusters to the Local Group
• EDGE: The emergence of dwarf galaxy scaling relations from cosmological radiation-hydrodynamics simulations
• A jolt to the system: ram pressure on low-mass galaxies in simulations of the Local Group
• Discovery of a red backsplash galaxy candidate near M81
• The present-day gas content of simulated field dwarf galaxies
• EDGE: Dark matter core creation depends on the timing of star formation
• EDGE-INFERNO: Simulating every observable star in faint dwarf galaxies and their consequences for resolved-star photometric surveys
• Colour and infall time distributions of satellite galaxies in simulated Milky-Way analogs
• EDGE: the puzzling ellipticity of Eridanus II's star cluster and its implications for dark matter at the heart of an ultra-faint dwarf
• The emergence of globular clusters and globular-cluster-like dwarfs
• The Ly$\alpha$ and Continuum Origins Survey. III. Investigating the Link between Galaxy Morphology, Merger Properties and LyC Escape
• The CHIMERA Survey: The first CO detection in Leo T, the lowest mass known galaxy still hosting cold molecular gas
• Revisiting the Gas Dynamics of Henize 2-10: Possible Drivers of the Starburst
• RGB Tip distance to the faint gas-rich dwarf KK 153
• Forward-modelling the Luminosity, Distance, and Size distributions of the Milky Way Satellites