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Arxiv: JWST/CEERS sheds light on dusty star-forming galaxies: forming bulges, lopsidedness and outside-in quenching at cosmic noon Published: 7/14/2023 10:45:28 PM Updated: 5/16/2024 1:39:58 AM

Paper abstract: We investigate the morphology and resolved physical properties of a sample of22 IR-selected DSFG at cosmic noon using the JWST/NIRCam images obtained in theEGS field for the CEERS survey. The resolution of the NIRCam images allowed tospatially resolve these galaxies up to 4.4um and identify their bulge even whenextinguished by dust. The goal of this study is to obtain a betterunderstanding of the formation and evolution of FIR-bright galaxies byspatially resolving their properties using JWST in order to look through thedust and bridge the gap between the compact FIR sources and the larger opticalSFG. Based on RGB images from the NIRCam filters, we divided each galaxy intoseveral uniformly colored regions, fitted their respective SEDs, and measuredphysical properties. After classifying each region as SF or quiescent, weassigned galaxies to three classes, depending on whether active SF is locatedin the core, in the disk or in both. We find (i) that galaxies at a higher ztend to have a fragmented disk with a low core mass fraction. They are at anearly stage of bulge formation. When moving toward a lower z, the core massfraction increases, and the bulge growth is associated with a stabilization ofthe disk: the NIRCam data clearly point toward bulge formation in preexistingdisks. (ii) Lopsidedness is a common feature of DSFGs. It could have a majorimpact on their evolution; (iii) 23% of galaxies have a SF core embedded in aquiescent disk. They seem to be undergoing outside-in quenching, oftenfacilitated by their strong lopsidedness inducing instabilities. (iv) We showthat half of our galaxies with SF concentrated in their core are good SMGcounterpart candidates, demonstrating that compact SMGs are usually surroundedby a larger, less obscured disk. (v) Finally, we found surprising evidence forclump-like substructures being quiescent or residing in quiescent regions.