Do fragmentation and accretion affect the stellar Initial Mass Function?
  While the stellar Initial Mass Function (IMF) appears to be close to
universal within the Milky Way galaxy, it is strongly suspected to be different
in the primordial Universe, where molecular hydrogen cooling is less efficient
and the gas temperature can be higher by a factor of 30. In between these
extreme cases, the gas temperature varies depending on the environment,
metallicity and radiation background. In this paper we explore if changes of
the gas temperature affect the IMF of the stars considering fragmentation and
accretion. The fragmentation behavior depends mostly on the Jeans mass at the
turning point in the equation of state where a transition occurs from an
approximately isothermal to an adiabatic regime due to dust opacities. The
Jeans mass at this transition in the equation of state is always very similar,
independent of the initial temperature, and therefore the initial mass of the
fragments is very similar. Accretion on the other hand is strongly temperature
dependent. We argue that the latter becomes the dominant process for star
formation efficiencies above 5 - 7 %, increasing the average mass of the stars.
