Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Challenges of Relativistic Astrophysics   I discuss some of the most outstanding challenges in relativistic
astrophysics in the subjects of: compact objects (Black Holes and Neutron
Stars); dark sector (Dark Matter and Dark Energy); plasma astrophysics (Origin
of Jets, Cosmic Rays and Magnetic Fields) and the primordial universe (Physics
at the beginning of the Universe). In these four subjects, I discuss twelve of
the most important challenges. These challenges give us insight into new
physics that can only be studied in the large scale Universe. The near future
possibilities, in observations and theory, for addressing these challenges, are
also discussed.

33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat
3
The categories of this paper are: physics
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat