Galactic archaeology: IMF and depletion in the "thin disk"

K. -P. Schröder; B. Pagel

doi:10.1046/j.1365-8711.2003.06763.x

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arXiv · astro-ph/0303013

Galactic archaeology: IMF and depletion in the "thin disk"

K. -P. Schröder·B. Pagel

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Abstract

We determine the initial mass function (IMF) of the ``thin disk'' by means of a direct comparison between synthetic stellar samples (for different matching choices of IMF, star formation rate SFR and depletion) and a complete (volume-limited) sample of single stars near the galactic plane (|z| < 25pc), selected from the Hipparcos catalogue (d < 100pc, M_v < +4.0). Our synthetic samples are computed from first principles: stars are created with a random distribution of mass M_* and age t_* which follow a given (genuine) IMF and SFR(t_*). They are then placed in the HR diagram by means of a grid of empirically well-tested evolution tracks. The quality of the match (synthetic versus observed sample) is assessed by means of star counts in specific regions in the HR diagram. 7 regions are located along the MS (main sequence, mass sensitive), while 4 regions represent different evolved (age-sensitive) stages of the stars. The counts of evolved stars, in particular, give valuable evidence of the history of the ``thin disk'' (apparent) star formation and lift the ambiguities in models restricted to MS star counts.

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K. -P. Schröder, B. Pagel. 2003-03-02. Galactic archaeology: IMF and depletion in the "thin disk". https://doi.org/10.1046/j.1365-8711.2003.06763.x

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