Starburst Galaxies in Their Last Billion Years: An H${\delta}$ Absorption Line Selected Sample

TL;DR

This study investigates the final billion years of starburst galaxies using Hδ absorption lines, proposing a new classification method and analyzing spectral features to understand their evolution and the role of AGNs.

Contribution

It introduces a novel classification approach based on SFR and UVJ colors for starburst galaxies selected by Hδ absorption, and explores their spectral evolution and AGN influence.

Findings

Increase in F- and G-type stars during galaxy evolution

Identification of AGNs in late-stage starburst galaxies

Spectral analysis reveals evolutionary trends in stellar populations

Abstract

In this paper, we focus on the study of starburst galaxies in their final billion years. Our galaxy selection is based solely on the presence of the H${\delta}$ absorption line, which permits tracing the later evolution of starburst galaxies, coinciding with the emergence of A-type stars in these galaxies. We propose a novel method that utilizes star formation rate and UVJ colors to classify galaxies in the sample, and use the spectral features to mark their evolution stages. Our in-depth analysis of the MgII line indicates the substantial increasing of F- and G-type stars when a galaxy evolves from star forming to quiescent phase. Furthermore, we identify AGNs in this sample to explore their roles in the later stage of galaxy star formation history.