On the origin of the peak of the stellar initial mass function:
  exploring the tidal screening theory
  Classical theories for the stellar initial mass function (IMF) predict a peak
mass which scales with the properties of the molecular cloud. In this work, we
explore a new theory proposed by Lee & Hennebelle (2018). The idea is that the
tidal field around first Larson cores prevents the formation of other
collapsing clumps within a certain radius. The protostar can then freely
accrete the gas within this radius. This leads to a peak mass of roughly $10 \,
M_{\mathrm{1LC}}$, independent of the parent cloud properties. Using simple
analytical arguments, we derive a collapse condition for clumps located close
to a protostar. We then study the tidal field and the corresponding collapse
condition using a series of numerical simulations. We find that the tidal field
around protostars is indeed strong enough to prevent clumps from collapsing
unless they have high enough densities. For each newly formed protostar, we
determine the region in which tidal screening is dominant. We call this the
tidal bubble. The mass within this bubble is our estimate for the final mass of
the star. Using this formalism, we are able to construct a very good prediction
for the final IMF in our simulations. Not only do we correctly predict the
peak, but we are also able to reproduced the high and low mass end of the IMF.
We conclude that tidal forces are important in determining the final mass of a
star and might be the dominant effect in setting the peak mass of the IMF.
