The Evolution of Post-Starburst Galaxies from $z\sim1$ to the Present

TL;DR

This study presents the largest sample of post-starburst galaxies from SDSS, analyzing their luminosity functions and evolution from redshift 1 to the present, revealing insights into galaxy quenching and downsizing.

Contribution

It provides a comprehensive analysis of post-starburst galaxy evolution over cosmic time using an unprecedented large spectroscopic dataset.

Findings

Luminosity functions are well fit by half-Gaussian functions.

Peak magnitudes shift with redshift, supporting downsizing.

Luminous post-starburst galaxies account for only about 1% of star-formation quenching.

Abstract

Post-starburst galaxies are in the transitional stage between blue, star-forming galaxies and red, quiescent galaxies, and therefore hold important clues for our understanding of galaxy evolution. In this paper, we systematically searched for and identified a large sample of post-starburst galaxies from the spectroscopic dataset of the Sloan Digital Sky Survey (SDSS) Data Release 9. In total, we found more than 6000 objects with redshifts between $z\sim0.05$ and $z\sim1.3$, making this the largest sample of post-starburst galaxies in the literature. We calculated the luminosity function of the post-starburst galaxies using two uniformly selected subsamples: the SDSS Main Galaxy Sample and the Baryon Oscillation Spectroscopic Survey CMASS Sample. The luminosity functions are reasonably fit by half-Gaussian functions. The peak magnitudes shift as a function of redshift from $M\sim-23.5$ at $z\sim0.8$ to $M\sim-20.3$ at $z\sim0.1$. This is consistent with the downsizing trend, whereby more massive galaxies form earlier than low-mass galaxies. We compared the mass of the post-starburst stellar population found in our sample to the decline of the global star-formation rate and found that only a small amount ($\sim1\%$) of all star-formation quenching in the redshift range $z=0.2-0.7$ results in post-starburst galaxies in the luminosity range our sample is sensitive to. Therefore, luminous post-starburst galaxies are not the place where most of the decline in star-formation rate of the universe is happening.