Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Testing dissipative dark matter in causal thermodynamics   In this paper we study the consistency of a cosmological model representing a
universe filled with a one-component dissipative dark matter fluid, in the
framework of the causal Israel-Stewart theory, where a general expression
arising from perturbation analysis for the relaxation time $\tau$ is used. This
model is described by an exact analytic solution recently found in [N. Cruz, E.
Gonz\'alez and G. Palma, Gen. Rel. Grav. \textbf{52}, 62 (2020), which depends
on several model parameters as well as integration constants, allowing the use
of Type Ia Supernovae and Observational Hubble data to perform an astringent
observational test. The constraint regions found for the parameters of the
solution allow the existence of an accelerated expansion of the universe at
late times, after the domination era of the viscous pressure, which holds
without the need of including a cosmological constant. Nevertheless, the fitted
parameter values lead to drawbacks as a very large non-adiabatic contribution
to the speed of sound, and some inconsistencies, not totally conclusive, with
the description of the dissipative dark matter as a fluid, which is
nevertheless a common feature of these kind of models.

1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
35
The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th