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

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.

10 pages, 3 figures, submitted to MNRAS

References in corpus (10)

• On the variation of the Initial Mass Function
• The Evolution of the Elemental Abundances in the Gas and Dust Phases of the Galaxy
• The Age of the Solar Neighbourhood
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• Chemical Evolution of Galaxies

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• Bolocam Survey for 1.1 mm Dust Continuum Emission in the c2d Legacy Clouds. II. Ophiuchus
• Comparing Star Formation on Large Scales in the c2d Legacy Clouds: Bolocam 1.1 mm Dust Continuum Surveys of Serpens, Perseus, and Ophiuchus
• The Emergence of the Thick Disk in a CDM Universe II: Colors and Abundance Patterns
• Recovering the star formation rate in the solar neighborhood
• BANYAN. IX. The Initial Mass Function and Planetary-Mass Object Space Density of the TW Hya Association
• A critical test of empirical mass loss formulae applied to individual giants and supergiants
• The Effect of Star Formation History on the Inferred Initial Stellar Mass Function
• What a Local Sample of Spectroscopic Binaries can tell us about the Field-Binary Population
• Born Again Protoplanetary Disk Around Mira B
• Consequences of Disk Scale Height on LISA Confusion Noise from Close White Dwarf Binaries
• The stellar metallicity distribution of disc galaxies and bulges in cosmological simulations
• Metallicity gradients of disc stars for a cosmologically simulated galaxy
• Fifty Years of IMF Variation: The Intermediate-Mass Stars
• The High Mass Slope of the IMF
• Pairing function of visual binary stars
• The Small Magellanic Cloud through the lens of the James Webb Space Telescope : binaries and mass function within the galaxy outskirts
• A deep HST view of the open cluster NGC2158: binaries, mass functions, and M-dwarf discontinuity