Mid-IR Luminosity Functions: Inferred Dusty Cosmic Star Formation and Black Hole Accretion Histories from the JWST SMILES

Abstract Mid-infrared (mid-IR) observations are crucial for understanding galaxy evolution, tracing star formation, and active galactic nuclei (AGN) activity via dust emission. This work presents mid-IR galaxy luminosity functions (LFs) at 0.5 < z < 6, derived from the JWST Systematic Mid-infrared Instrument Legacy Extragalactic Survey (SMILES) program. We combine 8 MIRI bands (5–25 μ m) of SMILES and archival 23-band HST+JWST NIRCam photometry to construct an extensive catalog containing 2813 galaxies with sub- μ Jy level completeness in the mid-IR. We obtain monochromatic (in 5.6, 7.7, 10, 12.8, 15, 18, 21, and 25.5 μ m), L IR , and AGN LFs, with a limiting luminosity down to 10 9.5 L ⊙ at z = 0.5–1.0, ∼10 10.5 L ⊙ at z = 2.0–4.0, and to ∼10 11 L ⊙ at z = 4.0–6.0. With the unprecedented sensitivity and resolution of JWST, here we better constrain the faint-end slope and its evolution of the mid-IR LFs, quantifying the dusty cosmic star formation and black hole accretion histories out to z ∼ 5. These results provide essential insights to refine our understanding of the obscured star formation and galaxy-AGN co-evolution over cosmic time.