Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: X- and Gamma-ray Studies of Cas A: Exposing Core Collapse to the Core   In this review of X-ray and gamma-ray observations of Cas A, evidence is
discussed that Cas A was a Type Ib supernova of a Wolf-Rayet star with a main
sequence mass between 22-25 Msun, that exploded after stellar wind loss had
reduced its mass to ~6 Msun. The observed kinematics and the high Ti-44 yield
indicate that the supernova explosion was probably assymetric, with a kinetic
energy of ~2x10^51 erg.

8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th