For star-forming galaxies, we investigated a global relation between the polycyclic aromatic hydrocarbon (PAH) emission luminosity at 3.3um, L_PAH3.3_, and the infrared (8-1000um) luminosity, L_IR_, to understand how the PAH 3.3um feature relates to star-formation activity. With AKARI, we performed near-infrared (2.5-5um) spectroscopy of 184 galaxies having L_IR_~10^8^-10^13^L_{sun}. We classified the samples into infrared galaxies (IRGs: L_IR_10^12^L{sun}). We excluded sources likely to be contaminated by AGN activity, based on the rest-frame equivalent width of the PAH emission feature (; F{nu}{prop.to}{lambda}^{Gamma}). Of these samples, 13 IRGs, 67 LIRGs, and 20 ULIRGs show the PAH emission feature at {lambda}_rest=3.3um in their spectra. We find that the L_PAH3.3_/L_IR_ ratio considerably decreases toward the luminous end. Utilizing the mass and temperature of dust grains as well as the Br{alpha} emission for the galaxies, we discuss the cause of the relative decrease in the PAH emission with L_IR_.
Cone search capability for table J/PASJ/65/103/pah3 (Basic properties of the galaxies with a significant (table1) or non-significant (table2) detection of the PAH 3.3{mu}m emission feature)
Cone search capability for table J/PASJ/65/103/ir_gal (Properties of infra-red galaxies (table3), and Luminous Infra-Red Galaxies (table4))
