Dilution in elliptical galaxies: Implications for the relation between metallicity, stellar mass and star formation rate

Abstract

We investigate whether gradual dilution of the gas in some elliptical galaxies is the cause of a positive correlation between star formation rate (SFR) and gas-phase metallicity (Zg) at high stellar mass (M*) in the local Universe. To do this, two classes of massive (M* >= 10^10.5 Msun) galaxy are selected from the Sloan Digital Sky Survey (SDSS) and the Munich semi-analytic model of galaxy formation, L-Galaxies. The first class is selected by high specific star formation rates (sSFR) and high Zg, and the second class by low sSFR and low Zg. These criteria roughly distinguish disc-dominant galaxies from metal-poor, elliptical galaxies. In the semi-analytic model, the second class of galaxies obtain low sSFR and low Zg due to gradual dilution of the interstellar medium by accretion of metal-poor gas via infalling clumps and low-mass satellites. This occurs after a merger-induced starburst and the associated supernova feedback have quenched most of the original gas reservoir. A number of signatures of this evolution are present in these model galaxies at z=0, including low gas fractions, large central black holes, elliptical morphologies, old ages, and importantly, low (Zg-Z*) indicating dilution after star formation. Remarkably, all of these properties are also found in low-sSFR, low-Zg, massive galaxies in the SDSS-DR7. This provides strong, indirect evidence that some elliptical galaxies are undergoing gradual dilution after a gas-rich merger in the local Universe. This dilution scenario also explains the positive correlation between SFR and Zg measured in high-M* galaxies, and therefore has consequences for the local fundamental metallicity relation (FMR), which assumes a weak anti-correlation between SFR and Zg above 10^10.5 Msun.

19 pages, 17 figures, 1 table. Submitted to MNRAS

References in corpus (19)

• The hierarchical formation of the brightest cluster galaxies
• Galaxy Pairs in the Sloan Digital Sky Survey I: Star Formation, AGN Fraction, and the Luminosity/Mass-Metallicity Relation
• COLD GASS, an IRAM legacy survey of molecular gas in massive galaxies: I. Relations between H2, HI, stellar content and structural properties
• Clues to the Origin of the Mass-Metallicity Relation: Dependence on Star Formation Rate and Galaxy Size
• Emission-line Diagnostics of Low Metallicity AGN
• A fundamental relation between the metallicity, gas content, and stellar mass of local galaxies
• The Oxygen Abundances of Luminous and Ultraluminous Infrared Galaxies
• Tidally Triggered Star Formation in Close Pairs of Galaxies: Major and Minor Interactions
• Modelling Element Abundances in Semi-analytic Models of Galaxy Formation
• The mass-metallicity relation of interacting galaxies
• Ultraviolet through Infrared Spectral Energy Distributions from 1000 SDSS Galaxies: Dust Attenuation
• Halo and Galaxy Formation Histories from the Millennium Simulation: Public release of a VO-oriented and SQL-queryable database for studying the evolution of galaxies in the LambdaCDM cosmogony
• Candidate Tidal Dwarf Galaxies in Arp 305: Lessons on Dwarf Detachment and Globular Cluster Formation
• Galaxy And Mass Assembly (GAMA): The connection between metals, specific-SFR, and HI gas in galaxies: the Z-SSFR relation
• Ultraviolet, Optical, and Infrared Constraints on Models of Stellar Populations and Dust Attenuation
• Towards A Removal of Temperature Dependencies from Abundance Determinations
• A SINFONI Integral Field Spectroscopy Survey for Galaxy Counterparts to Damped Lyman-alpha Systems - IV. Masses and Gas Flows
• VGS31b: a highly inclined ring along a filament in a void. Implication for the cold accretion
• The Slow Flow Model of Dust Efflux in Local Star-Forming Galaxies

Cited by in corpus (21)

• De Re Metallica: The cosmic chemical evolution of galaxies
• SDSS IV MaNGA - Metallicity and nitrogen abundance gradients in local galaxies
• Both starvation and outflows drive galaxy quenching
• Galaxy metallicity scaling relations in the EAGLE simulations
• L-GALAXIES 2020: Spatially resolved cold gas phases, star formation and chemical enrichment in galactic discs
• The evolution of the cold interstellar medium in galaxies following a starburst
• Superluminous supernova progenitors have a half-solar metallicity threshold
• Coevolution of metallicity and star formation in galaxies to z=3.7: I. A fundamental plane
• Molecular gas as the driver of fundamental galactic relations
• L-GALAXIES 2020: The evolution of radial metallicity profiles and global metallicities in disc galaxies
• Resolution-independent modeling of environmental effects in semi-analytic models of galaxy formation that include ram-pressure stripping of both hot and cold gas
• Astraeus V: The emergence and evolution of metallicity scaling relations during the Epoch of Reionization
• Iron in galaxy groups and clusters: Confronting galaxy evolution models with a newly homogenised dataset
• Age, metallicity and star formation history of spheroidal galaxies in cluster at z~1.2
• Colour gradients of low-redshift galaxies in the DESI Legacy Imaging Survey
• The role of AGN on the structure, kinematics and evolution of ETGs in the Horizon simulations
• Local Volume HI Survey: the far-infrared radio correlation
• A semi-analytical perspective on massive galaxies at $z\sim 0.55$
• The evolution and dependence of the local mass-metallicity relation
• Estimating The Metallicity of Star-forming Early-type Galaxies
• What is the right way to quench star formation in semi-analytic model of galaxy formation?