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JWST CEERS probes the role of stellar mass and morphology in obscuring galaxies Published: 4/17/2023 9:00:01 PM Updated: 9/4/2023 1:26:17 PM

Paper abstract: In recent years, observations have uncovered a population of massive galaxiesthat are invisible or very faint in deep optical/near-infrared (near-IR)surveys but brighter at longer wavelengths. However, the nature of theseoptically dark or faint galaxies (OFGs; one of several names given to theseobjects) is highly uncertain. In this work, we investigate the drivers of dustattenuation in the JWST era. In particular, we study the role of stellar mass,size, and orientation in obscuring star-forming galaxies (SFGs) at 3 < z <7.5, focusing on the question of why OFGs and similar galaxies are so faint atoptical/near-IR wavelengths. We find that stellar mass is the primary proxy fordust attenuation, among the properties studied. Effective radius and axis ratiodo not show a clear link with dust attenuation, with the effect of orientationbeing close to random. However, there is a subset of highly dust attenuated(A_V > 1, typically) SFGs, of which OFGs are a specific case. For thissubset, we find that the key distinctive feature is their compact size (formassive systems with \log (M_{*}/M_{\odot}) > 10); OFGs exhibit a 30% smallereffective radius than the average SFG at the same stellar mass and redshift. Onthe contrary, OFGs do not exhibit a preference for low axis ratios (i.e.,edge-on disks). The results in this work show that stellar mass is the primaryproxy for dust attenuation and compact stellar light profiles behind the thickdust columns obscuring typical massive SFGs.