Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Future Evolution of the Intergalactic Medium in a Universe Dominated by
  a Cosmological Constant   We simulate the evolution of the intergalactic medium (IGM) in a universe
dominated by a cosmological constant. We find that within a few Hubble times
from the present epoch, the baryons will have two primary phases: one phase
composed of low-density, low-temperature, diffuse, ionized gas which cools
exponentially with cosmic time due to adiabatic expansion, and a second phase
of high-density, high-temperature gas in virialized dark matter halos which
cools much more slowly by atomic processes. The mass fraction of gas in halos
converges to ~40% at late times, about twice its calculated value at the
present epoch. We find that in a few Hubble times, the large scale filaments in
the present-day IGM will rarefy and fade away into the low-temperature IGM, and
only islands of virialized gas will maintain their physical structure. We do
not find evidence for fragmentation of the diffuse IGM at later times. More
than 99% of the gas mass will maintain a steady ionization fraction above 80%
within a few Hubble times. The diffuse IGM will get extremely cold and dilute
but remain highly ionized, as its recombination time will dramatically exceed
the age of the universe.

3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat