Nearby starburst galaxies

New multiaperture 1.65 and 2.2 micron photometry has been obtained for the central region of 132 nearby spirals which exhibit 2 orders of magnitude range in central 10 micron luminosity. The 1.65, 2.2, and 10 micron photometry together with optical spectroscopy indicate that the high, ~ 10^9^ L-sun_, central 10 micron luminosity is powered by massive star formation for the majority of objects in this sample. The large data base has led to the definition of a complete sample of 20 nearby, 15 <= D(Mpc) <= 40, "M82 type" starburst galaxies, the majority of which have not been previously recognized as such. The near-infrared properties of the central region of the starburst galaxies differ markedly from spirals of lower nuclear star formation activity, in the sense that they exhibit, on average, a higher central 2.2 micron luminosity, a more centrally peaked 2.2 micron luminosity profile, and slightly redder H-K colors. The results support the interpretation that, like M82, the central 2.2 micron luminosity of the starbursts is dominated by red supergiants. On the other hand, comparison with starburst models has revealed that, in contrast to the case of M82, it is not necessary to invoke a truncated initial mass function in order to match the starburst nuclei properties. M82 is anomalous in comparison with the starbursts identified in this study by virtue of an uncharacteristically high central 2.2 micron luminosity. If reddening to the late-type stars in M82 has been previously overestimated, however, the distinction between M82 and the other starbursts would be less obvious. The case for a truncated initial mass function in M82 would also be considerably weakened.