Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Active Gravitational Mass of a Heat Conducting Sphere Out of
  Hydrostatic Equilibrium   We obtain an expression for the active gravitational mass of a relativistic
heat conducting fluid, just after its departure from hydrostatic equilibrium,
on a time scale of the order of relaxation time. It is shown that an increase
of a characteristic parameter leads to larger (smaller) values of active
gravitational mass of collapsing (expanding) spheres, enhacing thereby the
instability of the system.

17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
19
The categories of this paper are: eess
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg