Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Galaxy alignments: Theory, modelling and simulations   The shapes of galaxies are not randomly oriented on the sky. During the
galaxy formation and evolution process, environment has a strong influence, as
tidal gravitational fields in the large-scale structure tend to align nearby
galaxies. Additionally, events such as galaxy mergers affect the relative
alignments of both the shapes and angular momenta of galaxies throughout their
history. These "intrinsic galaxy alignments" are known to exist, but are still
poorly understood. This review will offer a pedagogical introduction to the
current theories that describe intrinsic galaxy alignments, including the
apparent difference in intrinsic alignment between early- and late-type
galaxies and the latest efforts to model them analytically. It will then
describe the ongoing efforts to simulate intrinsic alignments using both N-body
and hydrodynamic simulations. Due to the relative youth of this field, there is
still much to be done to understand intrinsic galaxy alignments and this review
summarises the current state of the field, providing a solid basis for future
work.

10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys