Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gravitational Waves: A New Astronomy   Contemporary astronomy is undergoing a revolution, perhaps even more
important than that which took place with the advent of radioastronomy in the
1960s, and then the opening of the sky to observations in the other
electromagnetic wavelengths. The gravitational wave detectors of the LIGO/Virgo
collaboration have observed since 2015 the signals emitted during the collision
and merger of binary systems of massive black holes at a large astronomical
distance. This major discovery opens the way to the new astronomy of
gravitational waves, drastically different from the traditional astronomy based
on electromagnetic waves. More recently, in 2017, the detection of
gravitational waves emitted by the inspiral and merger of a binary system of
neutron stars has been followed by electromagnetic signals observed by the
$\gamma$ and X satellites, and by optical telescopes. A harvest of discoveries
has been possible thanks to the multi-messenger astronomy, which combines the
information from the gravitational wave with that from electromagnetic waves.
Another important aspect of the new gravitational astronomy concerns
fundamental physics, with the tests of general relativity and alternative
theories of gravitation, as well as the standard model of cosmology.

1
The categories of this paper are: cs
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th