Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A model for ultrarelativistic spherically symmetric Pre-Hawking
  radiating gravitational collapse   In this paper we present a simple but non-simplistic model of gravitational
collapse with thermal emission of pre-Hawking radiation. We apply Einstein
equations to a time-dependant spherically symmetric metric and an
ultrarelativistic stress-energy tensor. In our model, particles either radially
approach the center of the star as collapsing matter, or radially flee from it.

1
The categories of this paper are: cs
35
The categories of this paper are: mtrl-th
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci