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Color Gradients in M99: Stellar Populations or Dust?

  • Rosa A. González
  • A. Gustavo Bruzual
  • C. Gladis Magris
  • James R. Graham
Part of the Astrophysics and Space Science Library book series (ASSL, volume 209)

Abstract

González & Graham (1996a, b) discovered an azimuthal age gradient in the stellar population across one of the arms of M99, in what amounts to the first observational confirmation of a fundamental prediction of spiral density wave theory. A more exhaustive comparison of the color gradient with stellar population synthesis models seems to rule out a wave as old as 1010 yr, in favor of a duration of a few times 108 yr. By using new models that include the effects of mixed-in dust, we confirm that dust plays a minor role in the determination of the azimuthal color changes in this region of M99. We advance some possible new explanations for the overwhelming non-detection of convincing stellar population gradients across spiral arms.

Keywords

Star Formation Stellar Population Young Star Initial Mass Function Color Gradient 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • Rosa A. González
    • 1
  • A. Gustavo Bruzual
    • 2
  • C. Gladis Magris
    • 2
  • James R. Graham
    • 1
  1. 1.Astronomy DepartmentUniversity of CaliforniaBerkeleyUSA
  2. 2.Centro de Investigaciones de AstronomíaMéridaVenezuela

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