A population of massive galaxies invisible or very faint in deep
optical/near-infrared surveys, but brighter at longer wavelengths has been
uncovered in the past years. However, the nature of these optically dark/faint
galaxies (OFGs, among other nomenclatures) is highly uncertain. In this work,
we investigate the drivers of dust attenuation in the JWST era. Particularly,
we study the role of stellar mass, size, and orientation in obscuring
star-forming galaxies (SFGs) at 3<z<7.5, focusing on understanding why
galaxies like OFGs are so faint at optical/near-infrared wavelengths. We find
that stellar mass is the primary proxy of dust attenuation among those studied.
Effective radius and axis ratio do not show a clear link with dust attenuation,
with the effect of orientation close to random. However, there is a subset of
highly dust attenuated (AV>1, typically) SFGs, of which OFGs are a
specific case. For this subset, we find that the key distinctive feature is
their compact size (for massive systems with log(M∗/M⊙)>10),
exhibiting 30% smaller effective radius than the average SFGs at the same
stellar mass and redshift. On the contrary, they do not exhibit a preference
for low axis ratios (i.e., edge-on disks). The results in this work show
stellar mass as a primary proxy of dust attenuation and compact stellar light
profiles behind thick dust columns obscuring typical massive SFGs.Comment: Submitted to A&A. 13 pages, 9 figure