The Typical Massive Quiescent Galaxy at z ∼ 3 is a Post-starburst

D’Eugenio, C.; Daddi, E.; Gobat, R.; Strazzullo, V.; Lustig, P.; Delvecchio, I.; Jin, S.; Puglisi, A.; Calabró, A.; Mancini, C.; Dickinson, M.; Cimatti, A.; Onodera, M.

Abstract

We have obtained spectroscopic confirmation with Hubble Space Telescope WFC3/G141 of a first sizeable sample of nine quiescent galaxies at 2.4 < z < 3.3. Their average near-UV/optical rest-frame spectrum is characterized by low attenuation (AV ~ 0.6 mag) and a strong Balmer break, larger than the 4000 Å break, corresponding to a fairly young age of ~300 Myr. This formally classifies a substantial fraction of classically selected quiescent galaxies at z ~ 3 as post-starbursts, marking their convergence to the quenching epoch. The rapid spectral evolution with respect to z ~ 1.5 quiescent galaxies is not matched by an increase of residual star formation, as judged from the weak detection of [O ii]λ3727 emission, pointing to a flattening of the steep increase in gas fractions previously seen from z ~ 0 to 1.8. However, radio 3 GHz stacked emission implies either much stronger dust-obscured star formation or substantial further evolution in radio-mode AGN activity with respect to z ~ 1.5.

Citation

D’Eugenio, C., Daddi, E., Gobat, R., Strazzullo, V., Lustig, P., Delvecchio, I., …Onodera, M. (2020). The Typical Massive Quiescent Galaxy at z ∼ 3 is a Post-starburst. Astrophysical Journal Letters, 892(1), Article L2. https://doi.org/10.3847/2041-8213/ab7a96

• Journal Article Type: Article
• Acceptance Date: Feb 27, 2020
• Online Publication Date: Mar 20, 2020
• Publication Date: Mar 20, 2020
• Deposit Date: Apr 17, 2020
• Publicly Available Date: Apr 17, 2020
• Journal: Astrophysical Journal
• Print ISSN: 2041-8205
• Publisher: American Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 892
• Issue: 1
• Article Number: L2
• DOI: https://doi.org/10.3847/2041-8213/ab7a96
• Public URL: https://durham-repository.worktribe.com/output/1303926