The stellar and sub-stellar IMF of simple and composite populations

Understand

The current knowledge on the stellar IMF is documented.

• It appears to become top-heavy when the star-formation rate density surpasses about 0.1Msun/(yr pc^3) on a pc scale and it may become increasingly bottom-heavy with increasing metallicity and in increasingly massive early-type galaxies.
• It declines quite steeply below about 0.07Msun with brown dwarfs (BDs) and very low mass stars having their own IMF.
• The most massive star of mass mmax formed in an embedded cluster with stellar mass Mecl correlates strongly with Mecl being a result of gravitation-driven but resource-limited growth and fragmentation induced starvation.