SLIDE 1
Metallicity gradients in disc galaxies
Ho+2015
Sanchez+2013; Sanchez-Mengano +2016
What drives metallicity gradients in discs ?
Belfiore+2017
The oxygen abundance gradients of galaxies in the Eagle simulations - - PowerPoint PPT Presentation
The oxygen abundance gradients of galaxies in the Eagle simulations - - PowerPoint PPT Presentation
The oxygen abundance gradients of galaxies in the Eagle simulations Patricia B. Tissera Universidad Andres Bello Millennium Institute of Astrophysics Metallicity gradients in disc galaxies What drives metallicity gradients in Ho+2015 discs
SLIDE 2
SLIDE 3
Selected from 100 Mpc volume. At least ~2000 baryonic particles. Dynamical decomposition: O/H profiles determined for the disc components with at least 100 star forming regions. Local environment characterise by count-in-cell NCIC. Total sample of 592 simulated galaxies with a variety of morphologies in different environments.
- Y. Rosas-Guevara (UNAB), R. Machado (U.
Curitiba), T. Theuns (ICC), R. Bowers (ICC), C. Lagos (Perth)
SLIDE 4
EAGLE simulations: global properties
Three environments are defined: low (~100 members), intermediate (~300 members) and high (~100) density
SLIDE 5
Gas-phase abundances of disc galaxies: dependence on stellar mass
SLIDE 6
Gas-phase abundances of disc galaxies: dependence on stellar mass
LM HM LM HM
SLIDE 7
Dependence on recent star formation history
Discs with positive gas-phase metallicity gradients are found in galaxies which quenched the star formation activity before compared to those with negative in the same mass range. Galactic fountain are not efficiently working and could be a solution if they act in the central regions.
SLIDE 8
Galaxies selected not to have a recent merger event (1:10 & < 3Gyr) show a trend with stellar mass. They have D/T >0.5 on average. Galaxies selected by D/T > 0.5 and gas fraction > 0.15 show a trend with stellar mass. These galaxies show a larger dispersion for smaller masses.
Dependence on recent merger history and D/T
SLIDE 9
Dependence on environment
Fraction of galaxies with positive metallicity gradients Fraction of galaxies with recent mergers Fraction of gas-rich galaxies (>15%)
45% 40% 27%
SLIDE 10
Dependence on environment
Ma+2017 Tissera+2016
SLIDE 11
Summary
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Metallicity gradients of the EAGLE discs are negative, on average, albeit flatter than observations, S(OH) ~ -0.01 dex/kpc.
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Galaxies with no recent mergers determine a correlation with stellar mass; they have well-defined discs and are gas-rich. Galaxies with a recent merger show a flat relation.
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There is a dependence of gas-phase metallicity gradients on local environment since the merger rate and the gas fraction vary with environment. Results indicate too strong central outflows + weak impact of fountain accretion. On going work: evolution of the gas-phase metallicity gradients and the stellar metallicity gradients.