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arXiv · 2305.04953

CLEAR: The Morphological Evolution of Galaxies in the Green Valley

Vicente Estrada-Carpenter·Casey Papovich·Ivelina Momcheva·Gabriel Brammer·Raymond C. Simons·Nikko J. Cleri·Mauro Giavalisco·Jasleen Matharu·Jonathan R. Trump·Benjamin Weiner·Zhiyuan Ji
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Abstract

Quiescent galaxies having more compact morphologies than star-forming galaxies has been a consistent result in the field of galaxy evolution. What is not clear is at what point this divergence happens, i.e. when do quiescent galaxies become compact, and how big of a role does the progenitor effect play in this result? Here we aim to model the morphological and star-formation histories of high redshift (0.8 $<$ z $<$ 1.65) massive galaxies (log(M/M$\odot$) $>$ 10.2) with stellar population fits using HST/WFC3 G102 and G141 grism spectra plus photometry from the CLEAR (CANDELS Lyman-alpha Emission at Reionization) survey, constraining the star-formation histories for a sample of $\sim$ 400 massive galaxies using flexible star-formation histories. We develop a novel approach to classifying galaxies by their formation activity in a way that highlights the green valley population, by modeling the specific star-formation rate distributions as a function of redshift and deriving the probability that a galaxy is quiescent (PQ). Using PQ and our flexible star-formation histories we outline the evolutionary paths of our galaxies in relation to stellar mass, Sersic index, $R_{eff}$, and stellar mass surface density. We find that galaxies show no appreciable stellar mass growth after entering the green valley (a net decrease of 4$\%$) while their stellar mass surface densities increase by $\sim$ 0.25 dex. Therefore galaxies are becoming compact during the green valley and this is due to increases in Sersic index and decreases in $R_{eff}$.

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Vicente Estrada-Carpenter, Casey Papovich, Ivelina Momcheva, Gabriel Brammer, Raymond C. Simons, Nikko J. Cleri, Mauro Giavalisco, Jasleen Matharu, Jonathan R. Trump, Benjamin Weiner, Zhiyuan Ji. 2023-05-08. CLEAR: The Morphological Evolution of Galaxies in the Green Valley. https://doi.org/10.3847/1538-4357%2Facd4be

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