PRIMER and JADES reveal an abundance of massive quiescent galaxies at 2 < z < 5

Le résumé fourni par la source

ABSTRACT We select a mass-complete sample of 225 quiescent galaxies at $z>2$ with $M_*>10^{10}\, \mathrm{M}_\odot$ from PRIMER and JADES photometry spanning a total area of $\simeq 320$ sq. arcmin. Our analysis is restricted to only area with optical coverage in three Hubble Space Telescope (HST) ACS filters, which we show is important for selecting the most complete and clean samples. We investigate the contamination in our sample via James Webb Space Telescope (JWST) NIRSpec spectroscopy, $Chandra$ X-ray imaging, and ALMA interferometry, calculating a modest contamination fraction of $12.9_{-3.1}^{+4.0}$ per cent. The removal of HST data increases star-forming galaxy contamination by $\simeq 10$ per cent and results in a $\simeq 20$ per cent loss of candidates recovered from HST + JWST data combined. We calculate massive quiescent galaxy number densities at $2< z< 5$, finding values three times larger than pre-JWST estimates, but generally in agreement with more-recent and larger-area JWST studies. In comparison with simulations, we find that most can now reproduce the observed number density at $2< z < 3$; however, they still increasingly fall short at $z>3$, up to $\simeq 1$ dex. We place 14 of our $z>3$ massive quiescent galaxies on the BPT and WHaN diagrams using medium-resolution spectroscopic data from the EXCELS survey, finding a very high incidence of weak active galactic nucleus ($\simeq 50$ per cent), consistent with recent results at cosmic noon. This is interesting in the context of ‘maintenance-mode’ feedback, which is invoked in many simulations to prevent the re-ignition of quenched galaxies. To properly characterize the evolution of early massive quiescent galaxies, greater coverage in optical filters and significantly larger spectroscopic samples will be required.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.