On the sizes of z>2 Damped Lyman-alpha Absorbing Galaxies

TL;DR

This study analyzes the sizes and metallicities of z>2 Damped Lyman-alpha Absorbing Galaxies, supporting models where galaxy size correlates with metallicity and is influenced by feedback processes affecting star formation and gas outflows.

Contribution

It provides observational evidence linking galaxy size and metallicity at high redshift, supporting feedback-driven models of galaxy evolution.

Findings

Observed DLA galaxy sizes are consistent with metallicity-size predictions.

Strong correlation found between impact parameter and HI column density.

Results support feedback mechanisms influencing galaxy size and metallicity.

Abstract

Recently, the number of detected galaxy counterparts of z > 2 Damped Lyman-alpha Absorbers in QSO spectra has increased substantially so that we today have a sample of 10 detections. M{\o}ller et al. in 2004 made the prediction, based on a hint of a luminosity-metallicity relation for DLAs, that HI size should increase with increasing metallicity. In this paper we investigate the distribution of impact parameter and metallicity that would result from the correlation between galaxy size and metallicity. We compare our observations with simulated data sets given the relation of size and metallicity. The observed sample presented here supports the metallicity-size prediction: The present sample of DLA galaxies is consistent with the model distribution. Our data also show a strong relation between impact parameter and column density of HI. We furthermore compare the observations with several numerical simulations and demonstrate that the observations support a scenario where the relation between size and metallicity is driven by feedback mechanisms controlling the star-formation efficiency and outflow of enriched gas.