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The Galactic HII region luminosity function (LF) is an important metric forunderstanding global star formation properties of the Milky Way, but only a fewstudies have been done and all use relatively small numbers of HII regions. Weuse a sample of 797 first Galactic quadrant HII regions compiled from the WISECatalog of Galactic HII Regions to examine the form of the LF at multipleinfrared and radio wavelengths. Our sample is statistically complete for allregions powered by single stars of type O9.5V and earlier. We fit the LF ateach wavelength with single and double power laws. Averaging the results fromall wavelengths, the mean of the best-fit single power law index is$\langle\alpha\rangle=-1.75\,\pm\,0.01$. The mean best-fit double power lawindices are $\langle\alpha_1\rangle=-1.40\,\pm\,0.03$ and$\langle\alpha_2\rangle=-2.33\,\pm\,0.04$. We conclude that neither a singlenor a double power law is strongly favored over the other. The LFs show somevariation when we separate the HII region sample into subsets by heliocentricdistance, physical size, Galactocentric radius, and location relative to thespiral arms, but blending individual HII regions into larger complexes does notchange the value of the power law indices of the best-fit LF models. Theconsistency of the power law indices across multiple wavelengths suggests thatthe LF is independent of wavelength. This implies that infrared and radiotracers can be employed in place of H$\alpha$.

The Galactic HII Region Luminosity Function at Radio and Infrared Wavelengths