DESI Survey Validation Spectra Reveal an Increasing Fraction of Recently Quenched Galaxies at z 1

DOI: 
10.3847/2041-8213/acc9b5
Publication date: 
13/04/2023
Main author: 
Setton, David J.
IAA authors: 
Prada, Francisco
Authors: 
Setton, David J.;Dey, Biprateep;Khullar, Gourav;Bezanson, Rachel;Newman, Jeffrey A.;Aguilar, Jessica N.;Ahlen, Steven;Andrews, Brett H.;Brooks, David;de la Macorra, Axel;Dey, Arjun;Eftekharzadeh, Sarah;Font-Ribera, Andreu;A Gontcho, Satya Gontcho;Kremin, Anthony;Juneau, Stephanie;Landriau, Martin;Meisner, Aaron;Miquel, Ramon;Moustakas, John;Pearl, Alan;Prada, Francisco;Tarlé, Gregory;Siudek, Małgorzata;Weaver, Benjamin Alan;Zhou, Zhimin;Zou, Hu
Journal: 
Astrophysical Journal Letters
Publication type: 
Article
Volume: 
947
Pages: 
L31
Abstract: 
We utilize ~17,000 bright luminous red galaxies (LRGs) from the novel Dark Energy Spectroscopic Instrument Survey Validation spectroscopic sample, leveraging its deep (~2.5 hr galaxy<SUP>-1</SUP> exposure time) spectra to characterize the contribution of recently quenched galaxies to the massive galaxy population at 0.4 &lt; z &lt; 1.3. We use Prospector to infer nonparametric star formation histories and identify a significant population of recently quenched galaxies that have joined the quiescent population within the past ~1 Gyr. The highest-redshift subset (277 at z &gt; 1) of our sample of recently quenched galaxies represents the largest spectroscopic sample of post-starburst galaxies at that epoch. At 0.4 &lt; z &lt; 0.8, we measure the number density of quiescent LRGs, finding that recently quenched galaxies constitute a growing fraction of the massive galaxy population with increasing look-back time. Finally, we quantify the importance of this population among massive ( $\mathrm{log}({M}_{\star }/{M}_{\odot })$ &gt; 11.2) LRGs by measuring the fraction of stellar mass each galaxy formed in the gigayear before observation, f <SUB>1 Gyr</SUB>. Although galaxies with f <SUB>1 Gyr</SUB> &gt; 0.1 are rare at z ~ 0.4 (≲0.5% of the population), by z ~ 0.8, they constitute ~3% of massive galaxies. Relaxing this threshold, we find that galaxies with f <SUB>1 Gyr</SUB> &gt; 5% constitute ~10% of the massive galaxy population at z ~ 0.8. We also identify a small but significant sample of galaxies at z = 1.1-1.3 that formed with f <SUB>1 Gyr</SUB> &gt; 50%, implying that they may be analogs to high-redshift quiescent galaxies that formed on similar timescales. Future analysis of this unprecedented sample promises to illuminate the physical mechanisms that drive the quenching of massive galaxies after cosmic noon.
Database: 
ADS
URL: 
https://ui.adsabs.harvard.edu/#abs/2023ApJ...947L..31S/abstract
ADS Bibcode: 
2023ApJ...947L..31S
Keywords: 
Post-starburst galaxies;Galaxies;E+A galaxies;Galaxy quenching;Quenched galaxies;Galaxy spectroscopy;Redshift surveys;2176;573;424;2040;2016;2171;1378;Astrophysics - Astrophysics of Galaxies