Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the emergent System Mass Function: the contest between accretion and
  fragmentation   We propose a new model for the evolution of a star cluster's System Mass
Function (SMF). The model involves both turbulent fragmentation and competitive
accretion. Turbulent fragmentation creates low-mass seed proto-systems (i.e.
single and multiple protostars). Some of these low-mass seed proto-systems then
grow by competitive accretion to produce the high-mass power-law tail of the
SMF. Turbulent fragmentation is relatively inefficient, in the sense that the
creation of low-mass seed proto-systems only consumes a fraction, $\sim 23\%$
(at most $\sim 50\%$), of the mass available for star formation. The remaining
mass is consumed by competitive accretion. Provided the accretion rate onto a
proto-system is approximately proportional to its mass ($dm/dt \propto m$), the
SMF develops a power-law tail at high masses with the Salpeter slope ($\sim
-2.3$). If the rate of supply of mass accelerates, the rate of proto-system
formation also accelerates, as appears to be observed in many clusters.
However, even if the rate of supply of mass decreases, or ceases and then
resumes, the SMF evolves homologously, retaining the same overall shape, and
the high-mass power-law tail simply extends to ever higher masses until the
supply of gas runs out completely. The Chabrier SMF can be reproduced very
accurately if the seed proto-systems have an approximately log-normal mass
distribution with median mass $\sim 0.11 {\rm M}_{_\odot}$ and logarithmic
standard deviation $\sigma_{\log_{10}(M/{\rm M}_\odot)}\sim 0.47$).

15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
16
The categories of this paper are: stat