Query : 2019A&A...630A.125V

2019A&A...630A.125V - Astronomy and Astrophysics, volume 630A, 125-125 (2019/10-1)

He abundances in disc galaxies. I. Predictions from cosmological chemodynamical simulations.


Abstract (from CDS):

We investigate how the stellar and gas-phase He abundances evolve as a function of time within simulated star-forming disc galaxies with different star formation histories. We make use of a cosmological chemodynamical simulation for galaxy formation and evolution, which includes star formation as well as energy and chemical enrichment feedback from asymptotic giant branch stars, core-collapse supernovae, and Type Ia supernovae. The predicted relations between the He mass fraction, Y, and the metallicity, Z, in the interstellar medium of our simulated disc galaxies depend on the galaxy star formation history. In particular, dY/dZ is not constant and evolves as a function of time, depending on the specific chemical element that we choose to trace Z; in particular, dY/dXO and dY/dXC increase as a function of time, whereas dY/dXN decreases. In the gas-phase, we find negative radial gradients of Y, due to the inside-out growth of our simulated galaxy discs as a function of time; this gives rise to longer chemical enrichment timescales in the outer galaxy regions, where we find lower average values for Y and Z. Finally, by means of chemical-evolution models, in the galactic bulge and inner disc, we predict steeper Y vs. age relations at high Z than in the outer galaxy regions. We conclude that for calibrating the assumed Y - Z relation in stellar models, C, N, and C+N are better proxies for the metallicity than O because they show steeper and less scattered relations.

Abstract Copyright: © ESO 2019

Journal keyword(s): galaxies: abundances - galaxies: evolution - ISM: abundances - stars: abundances - hydrodynamics

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024
1 NGC 6397 GlC 17 40 42.09 -53 40 27.6     5.17     ~ 1965 0
2 NGC 6791 OpC 19 20 53.0 +37 46 41   10.52 9.5     ~ 1030 0
3 M 30 GlC 21 40 22.12 -23 10 47.5     7.10     ~ 1041 0
4 NAME Galactic Bulge reg ~ ~           ~ 4252 0

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