Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Astro2020 Decadal Science White Paper: The state of gravitational-wave
  astrophysics in 2020   While still in its infancy, the budding field of gravitational-wave astronomy
has so far exceeded most expectations, and the achievements that have already
been made bode well for the decade to come. While the discoveries made possible
by LIGO have captured the imagination of experts and nonexperts alike, it is
important when looking ahead to consider those discoveries in the context of
the field as a whole. Just as radio, optical, and x-ray radiation probe
different physical phenomena occurring on a range of length and energy scales,
the future of gravitational-wave astrophysics depends on our ability to open up
the entire spectrum. We will describe the scientific prospects for the field of
gravitational-wave astronomy as a whole as we enter the coming decade, and we
will place the specific contributions from a future space-based
gravitational-wave observatory within this context.

30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg