Spectroscopic monochromatic luminosities at 7.7 μm, νL_{ν spec} (7.7 μm), as a function of redshift. The SPICY PAH galaxies are shown with black diamonds with one-sigma error bars, and the IRS galaxies in a sample of Weedman & Houck (2008) are shown with red pluses and blue triangles for starburst-component of the IRAS-selected ULIRGs and all other starburst galaxies, respectively. A black broken line represents a limit of “maximum starburst” of Weedman & Houck (2008) fitted at z = 0.0–2.5.