Regulating Star Formation in Nearby Dusty Galaxies: Low Photoelectric Efficiencies in the Most Compact Systems

Star formation in galaxies is regulated by the heating and cooling interstellar medium. In particular, processing of molecular gas into stars will depend strongly on ratio to neutral around sites recent star-formation. this work, we combine mid-infrared (mid-IR) observations Polycyclic Aromatic Hydrocarbons (PAHs), dominant mechanism medium (ISM), with [C II], [O I], [Si II] fine-structure emission, strongest channels dense, gas. The IR line emission PAH measures photoelectric efficiency, a property ISM which dictates how much energy carried ultraviolet photons gets transferred We find that star-forming, luminous Great Observatories All-Sky LIRG Survey (GOALS) high surface densities have low efficiencies. These systems also have, average, higher ratios radiation field strength densities, larger average dust grain size distributions. data support scenario most compact more young star-forming regions per unit area, exhibit less efficient heating. conditions may be common at high-z, help explain star-formation rates cosmic noon. make predictions can investigated JWST.