Revealing the physical properties of gas accreting to haloes in the EAGLE simulations

Abstract

The inflow of cosmological gas onto haloes, while challenging to directly observe and quantify, plays a fundamental role in the baryon cycle of galaxies. Using the EAGLE suite of hydrodynamical simulations, we present a thorough exploration of the physical properties of gas accreting onto haloes -- namely, its spatial characteristics, density, temperature, and metallicity. Classifying accretion as ``hot'' or `` cold'' based on a temperature cut of $10^{5.5}\mathrm{K}$, we find that the covering fraction ($f_{\mathrm{cov}}$) of cold-mode accreting gas is significantly lower than the hot-mode, with $z=0$ $f_{\mathrm{cov}}$ values of $\approx 50\%$ and $\approx 80\%$ respectively. Active Galactic Nuclei (AGN) feedback in EAGLE reduces inflow $f_{\mathrm{cov}}$ values by $\approx 10\%$, with outflows decreasing the solid angle available for accretion flows. Classifying inflow by particle history, we find that gas on first-infall onto a halo is metal-depleted by $\approx 2$~dex compared to pre-processed gas, which we find to mimic the circum-galactic medium (CGM) in terms of metal content. We also show that high (low) halo-scale gas accretion rates are associated with metal-poor (rich) CGM in haloes below $10^{12}{M}_{\odot }$, and that variation in halo-scale gas accretion rates may offer a physical explanation for the enhanced scatter in the star-forming main sequence at low ($\lesssim 10^9{M}_{\odot }$) and high ($\gtrsim 10^{10}{M}_{\odot }$) stellar masses. Our results highlight how gas inflow influences several halo- and galaxy-scale properties, and the need to combine kinematic and chemical data in order to confidently break the degeneracy between accreting and outgoing gas in CGM observations.

24 pages, 13 figures. Final version accepted for publication in MNRAS

References in corpus (42)

• Array Programming with NumPy
• Cosmic Star Formation History
• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Cold streams in early massive hot haloes as the main mode of galaxy formation
• The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations
• Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations
• A census of baryons in the Universe from localized fast radio bursts
• Cold gas accretion in galaxies
• The COS-Halos Survey: Physical Conditions and Baryonic Mass in the Low-Redshift Circumgalactic Medium
• Moving mesh cosmology: tracing cosmological gas accretion
• Bimodal gas accretion in the Horizon-MareNostrum galaxy formation simulation
• The dark nemesis of galaxy formation: why hot haloes trigger black hole growth and bring star formation to an end
• The COS-Halos Survey: Metallicities in the Low-Redshift Circumgalactic Medium
• The Star Formation Main Sequence in the Hubble Space Telescope Frontier Fields
• Resolving small-scale cold circumgalactic gas in TNG50
• The impact of feedback on cosmological gas accretion
• The COS/UVES Absorption Survey of the Magellanic Stream. III: Ionization, Total Mass, and Inflow Rate onto the Milky Way
• MusE GAs FLOw and Wind (MEGAFLOW) II. A study of gas accretion around $z\approx 1$ star-forming galaxies with background quasars
• The LUVOIR Mission Concept Study Final Report
• Predictions for the Angular Dependence of Gas Mass Flow Rate and Metallicity in the Circumgalactic Medium
• Hunting for Galaxies and Halos in simulations with VELOCIraptor
• HI 21-centimetre emission from an ensemble of galaxies at an average redshift of one
• COS-Burst: Observations of the Impact of Starburst-Driven Winds on the Properties of the Circum-Galactic Medium
• The environmental dependence of gas accretion onto galaxies: quenching satellites through starvation
• The origin of the high-velocity cloud complex C
• The Cosmic Evolution of the Metallicity Distribution of Ionized Gas Traced by Lyman Limit Systems
• First results from SMAUG: Uncovering the Origin of the Multiphase Circumgalactic Medium with a Comparative Analysis of Idealized and Cosmological Simulations
• The formation of hot gaseous haloes around galaxies
• ALMA measures rapidly depleted molecular gas reservoirs in massive quiescent galaxies at z~1.5
• The role of atomic hydrogen in regulating the scatter of the mass-metallicity relation
• Galactic inflow and wind recycling rates in the EAGLE simulations
• Cold-Mode Accretion: Driving the Fundamental Mass-Metallicity Relation at z~2
• The impact of stellar and AGN feedback on halo-scale baryonic and dark matter accretion in the EAGLE simulations
• The Relationship Between Galaxy ISM and Circumgalactic Gas Metallicities
• An evolving and mass dependent ${\sigma }_{\text{sSFR}}$-${\mathrm{M}}_{\star }$ relation for galaxies
• Gas accretion regulates the scatter of the mass-metallicity relation
• Close-up view of a luminous star-forming galaxy at z=2.95
• Cool circumgalactic gas of passive galaxies from cosmological inflow
• On the detectability of visible-wavelength line emission from the local circumgalactic and intergalactic medium
• Molecular Gas Inflows and Outflows in Ultraluminous Infrared Galaxies at $z\sim 0.2$ and one QSO at $z=6.1$
• The CGM at Cosmic Noon with KCWI: Outflows from a Star-forming Galaxy at z=2.071
• Most of the cool CGM of star-forming galaxies is not produced by supernova feedback

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