Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thermodynamic perfect fluid spheres admitting an orthogonal flat
  synchronization   We analyze the interpretation as a thermodynamic perfect fluid in local
thermal equilibrium of the spherically symmetric perfect fluid solutions that
admit a flat synchronization orthogonal to the fluid flow. The ideal gas sonic
condition is examined for this family of metrics, and the macroscopic
conditions for physical reality are accurately tested for some specifc
solutions.

25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
3
The categories of this paper are: physics
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga