Evolution of Lyman Alpha Galaxies: Stellar Populations at z ~ 0.3

TL;DR

This study analyzes the stellar populations of 30 Lyman alpha emitting galaxies at z ~ 0.3, revealing they are older and more massive than their high-redshift counterparts, indicating significant evolution over cosmic time.

Contribution

First comprehensive spectral energy distribution fitting of a large sample of low-redshift LAEs, filling an 8 Gyr gap in galaxy evolution studies.

Findings

LAEs at z ~ 0.3 have ages 200 Myr - 10 Gyr and stellar masses 10^9 - 10^11 Msol.

These LAEs are older and more massive than high-redshift LAEs.

Low-redshift LAEs show higher metallicity and less variation in dust attenuation.

Abstract

We present the results of a stellar population analysis of 30 Lyman alpha emitting galaxies (LAEs) at z ~ 0.3, previously discovered with the Galaxy Evolution Explorer (GALEX). With a few exceptions, we can accurately fit model spectral energy distributions to these objects, representing the first time this has been done for a large sample of LAEs at z < 3, a gap of ~ 8 Gyr in the history of the Universe. From the 26/30 LAEs which we can fit, we find an age and stellar mass range of 200 Myr - 10 Gyr and 10^9 - 10^11 Msol, respectively. These objects thus appear to be significantly older and more massive than LAEs at high-redshift. We also find that these LAEs show a mild trend towards higher metallicity than those at high redshift, as well as a tighter range of dust attenuation and interstellar medium geometry. These results suggest that low-redshift LAEs have evolved significantly from those at high redshift.