Morphological and Star Formation Properties of Cosmic Noon Massive Quiescent Galaxies

Abstract

We analyze the star formation and morphological properties of massive quiescent galaxies at cosmic noon ($2<z<3$) in the Abell 2744 field, using deep JWST NIRCam broadband and medium-band imaging from the UNCOVER Treasury program and the MegaScience survey, complemented by archival HST data. Using BAGPIPES SED modeling, we select 14 unique massive quiescent galaxies ($M_{\ast }\gtrsim 10^{10}$ M${}_{\odot }$, $\mathrm{sSFR}<0.2/t_{\mathrm{age}}$). Morphological analysis with statmorph and pysersic reveals that most galaxies are intermediate type or S0s with a median Sérsic index $n\sim 4$, consistent with bulge-dominated systems. This value remains constant over $z\sim 1.5$--$4$, indicating that the morphology of massive galaxies is linked to their quiescence since at least $z\sim 4$. Spatially resolved SED modeling with piXedfit shows that 11 out of 14 galaxies exhibit positive radial sSFR gradients, providing direct evidence for inside-out quenching, with the mean sSFR increasing by $\sim 2$ dex from $R/R_e=0.5$ to $4.5$. Formation time ($t_{50}$) profiles confirm that inner regions formed $\approx 0.5$ Gyr earlier, on average, than the outer regions, and quenching timescale profiles show that the cores were quenched more rapidly than the outskirts. Most galaxies are compact, with a mean half-mass radius of $R_e=1.95\pm 0.13$ kpc. The observed inside-out quenching pattern is consistent with quenching driven by AGN feedback, while the bulge-dominated morphologies suggest morphological quenching may also contribute.

28 pages, 13 figures, Accepted for publication in the Astrophysical Journal (ApJ)