SED-inferred properties and morphology of Lyman-break galaxies at $z\sim 1$ in the CDF-S

TL;DR

This study refines a sample of Lyman-break galaxies at redshift ~1, analyzing their properties, morphology, and star formation, revealing a dominance of disk-like structures and a size-mass relation linked to galaxy evolution.

Contribution

It provides an updated, detailed analysis of LBGs at z~1, combining photometric, morphological, and evolutionary insights with new correlations and a focus on disk-like galaxy dominance.

Findings

LBGs at z~1 are mainly disk-like galaxies.

Strong size-stellar mass correlation exists among LBGs.

A clear 'downsizing' effect is observed in the galaxy population.

Abstract

After carefully cross-identifying a previously discovered GALEX-selected Lyman Break Galaxy (LBG) candidates one-to-one with their optical counterparts in the field of the CDF-S, we re-estimate their photometric redshifts using multi-wavelength data from UV, optical to NIR. We refine a new updated sample of 383 LBGs at $0.7\la z \la 1.4$. Most LBGs are classified as starburst and irregular types. Ages spread from several Myr to 1.5Gyr. Their dust-corrected star formation rates (SFRs) and stellar masses ($M_*$) are from $4\my$ to $220\my$ and from $2.3\times 10^8 \msun$ to $4 \times 10^{11} \msun$. The rest-frame FUV luminosity function of LBGs are presented. LBGs of irregular types mainly distribute along the "main sequence" of star forming galaxies while most LBGs of starburst types locate in the starburst region. A "downsizing" effect is clearly found and LBGs distribute in the "blue" cloud. HST images in F606W ($V$ band) and F850LP ($z$ band) are taken from the GEMS and GOODS-S surveys. SExtractor and GALFIT are applied to get their morphological parameters. A morphological sample of 142 LBGs with reliable results of $\sersic$ and sizes in both bands is defined. We find that LBGs at $z\sim 1 $ are dominated by disk-like galaxies. Correlations between photometric and morphological properties of LBGs are investigated. Strong correlations between their half-light radii and $M_*$, i.e., size-stellar mass relations, are found in both bands. Physical connections between correlations and the "downsizing" effect are discussed.