Galaxy Evolution in Cosmological Simulations with Outflows II: Metallicities and Gas Fractions

By R. Dav'e, K. Finlator, B. Oppenheimer. 2011

334 citations recorded by the source corpus.

We use cosmological hydrodynamic simulations to investigate how inflows, star formation, and outflows govern the the gaseous and metal content of galaxies within a hierarchical structure formation context. In our simulations, galaxy metallicities are established by a balance between inflows and outflows as governed by the mass outflow rate, implying that the mass-metallicity relation reflects how the outflow rate varies with stellar mass. Gas content, meanwhile, is set by a competition between inflow into and gas consumption within the interstellar medium, the latter being governed by the star formation law, while the former is impacted by both wind recycling and preventive feedback. Stochastic variations in the inflow rate move galaxies off the equilibrium mass-metallicity and mass-gas fraction relations in a manner correlated with star formation rate, and the scatter is set by the timescale to re-equilibrate. The evolution of both relations from z = 3 ! 0 is slow, as individual galaxies tend to evolve mostly along the relations. Gas fractions at a given stellar mass slowly decrease with time because the cosmic inflow rate diminishes faster than the consumption rate, while metallicities slowly increase as infalling gas becomes more enriched. Observations from z � 3 ! 0 are better matched by simulations employing momentum-driven wind scalings rather than constant wind speeds, but all models predict too low gas fractions at low masses and too high metallicities at high masses. All our models reproduce observed second-parameter trends of the mass-metallicity relation with star formation rate and environment, indicating that these are a consequence of equilibrium and not feedback. Overall, the analytical framework of our equilibrium scenario broadly captures the relevant physics establishing the galaxy gas and metal content in simulations, which suggests that the cycle of baryonic inflows and outflows centrally governs the cosmic evolution of these properties in typical star-forming galaxies.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/a10301a89748ccee2c602f847cf02254c916ac3a

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Citations in the corpus

PRIMUS: CONSTRAINTS ON STAR FORMATION QUENCHING AND GALAXY MERGING, AND THE EVOLUTION OF THE STELLAR MASS FUNCTION FROM z = 0–1 (2013, background): “However, many discrepancies between observations and predictions persist (e.g., Fontana et al. 2006; Fontanot et al. 2009; Kereš et al. 2009; Davé et al. 2011a,b; Lu et al. 2012; Weinmann et al. 2012).”
THE RELATION BETWEEN STAR FORMATION RATE AND STELLAR MASS FOR GALAXIES AT 3.5 ⩽ z ⩽ 6.5 IN CANDELS (2014, background): “…and a multi-phase ISM model following Springel & Hernquist (2003), and galactic outflows assuming momentum-driven wind scalings which have been shown to be crucial for providing a reasonable match to a variety of IGM and galaxy properties from z ∼ 0 − 4 and beyond (see Davé et al. 2011b,a).”
SHORT-LIVED STAR-FORMING GIANT CLUMPS IN COSMOLOGICAL SIMULATIONS OF z ≈ 2 DISKS (2010, background): “The baryon conversion efficiency is a strong function of mass in our simulations, though not as strong as observations indicate, such that small dark matter halos in our simulations probably host too massive galaxies (see also Davé et al. 2011b).”
DEMOGRAPHICS AND PHYSICAL PROPERTIES OF GAS OUTFLOWS/INFLOWS AT 0.4 < z < 1.4 (2012, background): “At least in some models, however, recyling of the metals carried to large distances by winds substantially increases the metallicity of the infalling gas (Oppenheimer et al. 2008; Davé et al. 2011b).”
A fundamental problem in our understanding of low-mass galaxy evolution (2012, methodology): “Interestingly, these momentum-driven wind models seem to suffer from similar problems as the semianalytic models mentioned above regarding the evolution of the mass function and the star formation rates (Davé 2008; Davé et al. 2011a).”
The cosmic baryon cycle and galaxy mass assembly in the FIRE simulations (2016, background): “…2014; Agertz & Kravtsov 2015a; Ma et al. 2016a), and reproduce key observables including the galaxy stellar mass function (Oppenheimer et al. 2010; Davé et al. 2011a; Vogelsberger et al. 2014), the mass–metallicity relation (Davé et al. 2011b; Torrey et al. 2014; Ma et al. 2016b), and the metal…”
New fully empirical calibrations of strong-line metallicity indicators in star forming galaxies (2016, background): “…to the enrichment of the interstellar medium (ISM), while cosmological infall of pristine gas from the intergalactic medium (IGM) and outflows due to Active Galactic Nuclei (AGNs) and supernovae could dilute the ISM and at the same time trigger new star formation episodes (Davé et al. 2011).”
THE COSMIC BPT DIAGRAM: CONFRONTING THEORY WITH OBSERVATIONS (2013, methodology): “In Kewley et al. (2013), we combine the chemical evolution predictions from Davé et al. (2011) with the Starburst99 & Pegase2 evolutionary synthesis models (Leitherer et al. 1999; Fioc & Rocca-Volmerange 1999) and our Mappings IV photoionization code (Dopita et al. 2013).”
The origin and evolution of the galaxy mass–metallicity relation (2015, background): “Many cosmological simulations tend to form too many stars at early times (e.g. Davé et al. 2011a; Sparre et al. 2015; Fiacconi et al. 2015; for a review, see Somerville & Davé 2014.”
Dusty Star Forming Galaxies at High Redshift (2014, background): “This point has been predicted in theoretical models (e.g. Davé et al., 2010, 2011; Lagos et al., 2011; Popping et al., 2012, 2013b), as well as observationally confirmed (Combes et al., 2013; Saintonge et al., 2013; Tacconi et al., 2013; Santini et al., 2014).”
A survey of molecular gas in luminous sub-millimetre galaxies (2012, background): “Conversely, a gas fraction which rises with time represents a rapid accretion rate which swamps the consumption rate, leading to the accumulation of large gas reservoirs (thought to occur at z 4; Davé et al. 2011; Papovich et al. 2011).”
The role of cold gas and environment on the stellar mass-metallicity relation of nearby galaxies (2012, methodology): “Using cosmological hydrodynamic simulations, Davé et al. (2011) explore the effects of inflows, outflows and star formation in governing the gas and metal content.”
THE MASS–METALLICITY RELATION WITH THE DIRECT METHOD ON STACKED SPECTRA OF SDSS GALAXIES (2012, methodology): “The interplay between these three processes is complex, so hydrodynamic galaxy simulations (e.g., Brooks et al. 2007; Finlator & Davé 2008; Davé et al. 2011a, 2011b) and analytic models (e.g., Peeples & Shankar 2011; Davé et al. 2012) have been used to establish a framework to interpret the…”
Metallicity gradients in local field star-forming galaxies: insights on inflows, outflows, and the coevolution of gas, stars and metals (2015, background): “…mass return from both the stars and AGNs (i.e. “feedback”) are indispensable for numerical simulations to reproduce many observed properties of galaxies, such as the stellar mass function and mass-metallicity relation (e.g.,Springel & Hernquist 2003; Oppenheimer et al. 2010; Davé et al. 2011a,b).”
Shaping the galaxy stellar mass function with supernova- and AGN-driven winds (2012, methodology): “Davé et al. (2011b) used an updated version of the Oppenheimer & Davé (2006) momentum-driven model in which the galaxy velocity dispersion is instead estimated based on halo masses computed by an on-the-fly friend-of-friend group finder (Oppenheimer & Davé 2008).”
PHIBSS: Unified Scaling Relations of Gas Depletion Time and Molecular Gas Fractions (2017, background): “…formation rate, galaxy size/internal structure, gas motions and environmental parameters (e.g. Daddi et al. 2010a, b, Tacconi et al. 2010, 2013, Genzel et al. 2010, 2015, Bouché et al. 2010, Lilly et al. 2013, Davé et al. 2011, 1012, Lagos et al. 2011, 2015a,b, Fu et al. 2012, Popping et al. 2015).”
A BUDGET AND ACCOUNTING OF METALS AT z ∼ 0: RESULTS FROM THE COS-HALOS SURVEY (2013, background): “…highly efficient winds that remove large amounts of freshly produced metals are necessary to understand the ISM abundances of both local and high-redshift galaxies (e.g., Dalcanton 2007; Erb 2008; Finlator & Davé 2008; Arrigoni 2010; Peeples & Shankar 2011; Davé et al. 2011; Dayal et al. 2013).”