The Effects of Supergiants on the Infrared Light Distribution in Galaxies
Dynamical models require good estimates of the stellar surface mass density in galaxies. Surface brightness measurements in principle can trace the locations of the stars, but optical wavelength images are often confused by dust extinction and dominated by the light from a relatively few, bright young stars. Near–infrared images are much less affected by dust extinction (A k ≈ 0.1A v ) and, for a normal stellar population, relatively unaffected by the presence of young stars. For example, in a population of stars similar to that found in the disk of the Milky Way ∼92% of the total light at K is due to giant stars, ∼ 7% due to main sequence stars, and only ∼ 1% due to supergiants. Since main sequence stars, which dominate the mass, and giants are well–mixed in older populations (see Aaronson 1977 and Frogel 1988), K images should trace the mass effectively.
KeywordsStar Formation Equivalent Width Spiral Galaxy Young Star Main Sequence Star
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- Aaronson, M. 1977, Ph.D. Thesis, Harvard UniversityGoogle Scholar