Chemodynamical properties of gas-rich galaxies: a comparison of observations and simulations

TL;DR

This study compares the chemical and dynamical properties of gas-rich galaxies from observations and chemodynamical simulations, revealing insights into galaxy mass, metallicity, and velocity relations across different redshifts.

Contribution

It provides a detailed comparison between observed DLA galaxy properties and GEAR chemodynamical simulations, highlighting areas of agreement and calibration needs.

Findings

Observed [{}/Fe] and [M/H] overlap with simulated trends.

DLAs with 90 below/above 100 km/s trace different galaxy mass ranges.

Velocity width and mass-metallicity relations match observations, but 90 vs. metallicity needs calibration.

Abstract

We perform a comprehensive analysis of the chemical and dynamical properties of quasar-damped Lyman-{\alpha} (DLA) galaxies and compare these to the GEAR chemodynamical simulations. Specifically, we aim to constrain the behavior of {\alpha}-element enhancements with metallicity, the dependence of [{\alpha}/Fe] on the specific star formation rate (sSFR), and the absorption-line velocity widths ({\Delta}v90) vs. stellar mass, {\Delta}v90 vs. metallicity, and mass-metallicity relations. For the comparison, we select five galaxies simulated with the chemodynamical Tree-SPH code GEAR with stellar masses in the range of log(M*/Msol) between 6.1 and 10.8, and at six different redshifts between 0.33 and 4.12. We find that the abundance ratios [{\alpha}/Fe] and [M/H] observed in the interstellar medium (ISM) of DLA galaxies overlap with the abundance trends in gas of the simulated galaxies. Our findings corroborate a picture in which DLAs with {\Delta}v90 below and above 100 km/s trace galaxies with masses in the ranges of log M* 6 - 8 and 8 - 11 solar masses, respectively. We suggest that observations should be used with caution when constraining the theoretical [{\alpha}/Fe] vs. sSFR relations because of systematics (if abundances are obtained from emission lines) or differences in the gas properties as probed by a DLA and its counterpart. So far, only the observations in absorption of inner gas of the LMC and SMC are in agreement with the simulated data. We confirm that DLAs detected at large impact parameters most likely probe the gas of satellite or other halo galaxies which are adjacent to the central galaxy. We further find that the velocity widths vs. stellar masses and mass-metallicity relations agree well with observations, while GEAR should be calibrated more carefully to reproduce the {\Delta}v90 vs. metallicity relation.