A longstanding question in extragalactic astronomy is how many dusty galaxies and accreting black holes remain undetected, even in the deepest observational surveys. A substantial population of faint, dust-obscured sources lies below the sensitivity limits of previous space-based infrared facilities such as Spitzer (85 cm) and AKARI (65 cm). The advent of the 6.5 m James Webb Space Telescope (JWST) represents a transformative advance in infrared astronomy. With sensitivities more than two orders of magnitude greater than its predecessors, JWST enables the detection of a previously inaccessible population of faint infrared sources.

Dusty galaxies and active galactic nuclei (AGN) exhibit distinct mid-infrared signatures. AGN are characterized by strong emission from hot dust, while dusty star-forming galaxies are dominated by prominent polycyclic aromatic hydrocarbon (PAH) features. The JWST PRIMER/SMILES fields provide a mid-infrared survey area approximately 17 times larger than that of the Early Release Observations, offering an unprecedented combination of depth and areal coverage. Leveraging this capability, we aim to identify dusty galaxies, accreting black holes, and brown dwarfs that have remained beyond the reach of previous facilities.