Chemical Abundances of Early Quiescent Galaxies: New Observations and Modelling Impacts

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Autori principali: Jafariyazani, Marziye, Newman, Andrew B., Mobasher, Bahram, Belli, Sirio, Ellis, Richard S., Faisst, Andreas L.
Natura: Preprint
Pubblicazione: 2024
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author Jafariyazani, Marziye
Newman, Andrew B.
Mobasher, Bahram
Belli, Sirio
Ellis, Richard S.
Faisst, Andreas L.
author_facet Jafariyazani, Marziye
Newman, Andrew B.
Mobasher, Bahram
Belli, Sirio
Ellis, Richard S.
Faisst, Andreas L.
contents Recent stellar chemical abundance measurements of a handful of $z\sim2$ quiescent galaxies have suggested these galaxies exhibit a remarkably strong $α$-enhancement compared to their local and intermediate redshift counterparts. This apparent chemical evolution following quenching suggests that even the innermost regions of massive early-type galaxies may have experienced substantial mixing of stars in mergers, challenging a purely inside-out growth model. However, larger samples are needed to determine whether a high $α$-enhancement ([Mg/Fe] $\approx 0.5$) is common in $z \sim 2$ quiescent galaxies, and a comparative analysis is needed to determine whether it is consistently inferred using different stellar population synthesis models. We report age and stellar chemical abundance measurements for a sample of four gravitationally lensed quiescent galaxies at $z\sim2.1-2.65$ based on Magellan/FIRE spectroscopy. For three of these galaxies we constrain the $α$-enhancement, and in two cases we measure high values comparable to earlier results when the spectra are analyzed consistently. We also find that the choice of modeling approach can exert a significant effect on the measured abundances. This model dependence can be partly, but not entirely, explained by the complex abundance patterns of $α$ elements in galaxies, which has been observed at lower redshifts and in one $z \sim 2$ quiescent galaxy. Our investigation highlights the importance of independently varying abundance of $α$ elements when fitting the spectra of such galaxies. Observations with JWST will soon deliver precise and spatially resolved abundances of these and other quiescent galaxies at cosmic noon, opening a new window into their evolution.
format Preprint
id arxiv_https___arxiv_org_abs_2406_03549
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Chemical Abundances of Early Quiescent Galaxies: New Observations and Modelling Impacts
Jafariyazani, Marziye
Newman, Andrew B.
Mobasher, Bahram
Belli, Sirio
Ellis, Richard S.
Faisst, Andreas L.
Astrophysics of Galaxies
Recent stellar chemical abundance measurements of a handful of $z\sim2$ quiescent galaxies have suggested these galaxies exhibit a remarkably strong $α$-enhancement compared to their local and intermediate redshift counterparts. This apparent chemical evolution following quenching suggests that even the innermost regions of massive early-type galaxies may have experienced substantial mixing of stars in mergers, challenging a purely inside-out growth model. However, larger samples are needed to determine whether a high $α$-enhancement ([Mg/Fe] $\approx 0.5$) is common in $z \sim 2$ quiescent galaxies, and a comparative analysis is needed to determine whether it is consistently inferred using different stellar population synthesis models. We report age and stellar chemical abundance measurements for a sample of four gravitationally lensed quiescent galaxies at $z\sim2.1-2.65$ based on Magellan/FIRE spectroscopy. For three of these galaxies we constrain the $α$-enhancement, and in two cases we measure high values comparable to earlier results when the spectra are analyzed consistently. We also find that the choice of modeling approach can exert a significant effect on the measured abundances. This model dependence can be partly, but not entirely, explained by the complex abundance patterns of $α$ elements in galaxies, which has been observed at lower redshifts and in one $z \sim 2$ quiescent galaxy. Our investigation highlights the importance of independently varying abundance of $α$ elements when fitting the spectra of such galaxies. Observations with JWST will soon deliver precise and spatially resolved abundances of these and other quiescent galaxies at cosmic noon, opening a new window into their evolution.
title Chemical Abundances of Early Quiescent Galaxies: New Observations and Modelling Impacts
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2406.03549