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The stellar populations of gravitationally lensed quiescent galaxies at z ~ 2

Presentation #342.21 in the session “Galaxy Evolution & Populations”.

Published onJan 11, 2021
The stellar populations of gravitationally lensed quiescent galaxies at z ~ 2

Recent stellar chemical abundance measurements of two z ~ 2 quiescent galaxies have shown that these galaxies are α-enhanced compared to their local and intermediate redshift counterparts. This suggested that even the inner regions of massive early-type galaxies might have experienced mixing of stars in mergers, in contrast to a purely inside-out growth model. Moreover, for one of these galaxies (MRG-M0138), the high α-enhancement is observed simultaneously with a high [Fe/H]. This also challenges simple galactic chemical evolution models that vary only the star formation timescale because simply truncating the star formation can explain a high [α/Fe] but will require a low [Fe/H]. These show the need for further observations to understand if these two galaxies are representative of high redshift quiescent galaxies populations in general. Although, the compactness and faintness of these sources make spectroscopic analysis pretty challenging, thanks to the strong gravitational lensing we have the opportunity to study a few more sources. Here we present the new results of analyzing spectroscopic and photometric data of a handful of lensed quiescent galaxies at z ~ 2. Combining absorption line analysis with color gradients deduced from HST multiband images of these galaxies, we will further investigate the chemical composition and star formation history of quiescent galaxies near the epoch of quenching.


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