The effect of gas accretion on the radial abundance profiles of galaxies

COLLACCHIONI, FLORENCIA; CORA, SOFÍA A; MITCHELL, PETER D.; LAGOS, CLAUDIA

Viedma

Congreso; 61° Reunión Anual de la Asociación Argentina de Astronomía; 2019

Instituto Argentino de Radioastronomía (IAR)

The advent of integral field spectroscopy has allowed the characterization of radial gas metallicity profiles (RMPs) in many thousands of local galaxies and several dozens at high redshift. This has helped in finding that radial gradients change as a function of stellar mass and star formation rate and, more surprisingly, that they flatten in the outskirts of galaxies. We study the physical causes of these trends using the state-of-the-art hydrodynamic simulation EAGLE and focusing specifically on central galaxies of M∗ ≥ 1010 M⊙. We find clear correlations between the gas accretion rate (dotMaccr) and the internal (within an effective radius) gradient of the RMP, in a way that higher dotMaccr are associated to larger gradients. The gradient of the RMPs is found to depend more strongly on dotMaccr than on stellar mass or star formation rate, suggesting the gas accretion to be a more fundamental driver of the RMP of galaxies. These trends are present in the simulation for the full range of redshift studied here (z ≤ 1).