Physical Properties of Local Star-Forming Analogues to z~5 Lyman Break Galaxies

TL;DR

This study identifies local star-forming galaxies with properties similar to high-redshift z~5 Lyman break galaxies, providing a valuable nearby analogue for understanding early galaxy evolution.

Contribution

We present a detailed analysis of local galaxies that closely resemble high-redshift LBGs, offering new insights into their physical properties and evolution.

Findings

Local analogues have similar stellar masses and star formation rates as z~5 LBGs.

These galaxies are young, moderately massive, with low dust extinction.

Their specific star formation rates match those of distant LBGs.

Abstract

Intense, compact, star-forming galaxies are rare in the local Universe but ubiquitous at high redshift. We interpret the 0.1-22 um spectral energy distributions (SED) of a sample of 180 galaxies at 0.05<z<0.25 selected for extremely high surface densities of inferred star formation in the ultraviolet. By comparison with well-established stellar population synthesis models we find that our sample comprises young (~ 60 - 400 Myrs), moderate mass (~ $6\times 10^9$ Msun) star-forming galaxies with little dust extinction (mean stellar continuum extinction $E_\mathrm{cont}$(B-V) ~ 0.1) and find star formation rates of a few tens of Solar masses per year. We use our inferred masses to determine a mean specific star formation rate for this sample of ~ $10^{-9}$ yr$^{-1}$, and compare this to the specific star formation rates in distant Lyman break galaxies (LBGs), and in other low redshift populations. We conclude that our sample's characteristics overlap significantly with those of the z~5 LBG population, making ours the first local analogue population well tuned to match those high redshift galaxies. We consider implications for the origin and evolution of early galaxies.