Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The baryonic mass function of galaxies   In the Big Bang about 5% of the mass that was created was in the form of
normal baryonic matter (neutrons and protons). Of this about 10% ended up in
galaxies in the form of stars or of gas (that can be in molecules, can be
atomic, or can be ionised).
  In this work, we measure the baryonic mass function of galaxies, which
describes how the baryonic mass is distributed {\it within} galaxies of
different types (e.g. spiral or elliptical) and of different sizes. This can
provide useful constraints on our current cosmology, convolved with our
understanding of how galaxies form. This work relies on various large
astronomical surveys, for example the optical Sloan Digital Sky Survey (to
observe stars) and the HIPASS radio survey (to observe atomic gas). We then
perform an integral over our mass function to determine the cosmological
density in baryons in galaxies: $\Omega_{\rm b, gal} = 0.0035$. Most of these
baryons are in stars: $\Omega_{*} = 0.0028$. Only about 20% are in gas. The
error on the quantities, as determined from the range obtained between
different methods, is $\sim 10$%; systematic errors may be much larger.
  Most ($\sim 90$%) of the baryons in the Universe are not in galaxies. They
probably exist in a warm/hot intergalactic medium. Searching for direct
observational evidence and deeper theoretical understanding for this will form
one of the major challenges for astronomy in the next decade.

27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
9
The categories of this paper are: nlin
15
The categories of this paper are: nucl-ex
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The categories of this paper are: eess
31
The categories of this paper are: ao-sci
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The categories of this paper are: math-ph
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The categories of this paper are: econ
3
The categories of this paper are: physics