Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A multimessenger view of galaxies and quasars from now to mid-century   In the next 30 years, a new generation of space and ground-based telescopes
will permit to obtain multi-frequency observations of faint sources and, for
the first time in human history, to achieve a deep, almost synoptical
monitoring of the whole sky. Gravitational wave observatories will detect a
Universe of unseen black holes in the merging process over a broad spectrum of
mass. Computing facilities will permit new high-resolution simulations with a
deeper physical analysis of the main phenomena occurring at different scales.
  Given these development lines, we first sketch a panorama of the main
instrumental developments expected in the next thirty years, dealing not only
with electromagnetic radiation, but also from a multi-messenger perspective
that includes gravitational waves, neutrinos, and cosmic rays. We then present
how the new instrumentation will make it possible to foster advances in our
present understanding of galaxies and quasars. We focus on selected scientific
themes that are hotly debated today, in some cases advancing conjectures on the
solution of major problems that may become solved in the next 30 years.

2
The categories of this paper are: math
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex