Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Extreme Matter meets Extreme Gravity: Ultra-heavy neutron stars with
  crossovers and first-order phase transitions   The speed of sound of the matter within neutron stars may contain non-smooth
structure related to first-order phase transitions or or crossovers. Here we
investigate what are the observable consequences of structure, such as bumps,
spikes, step functions, plateaus, and kinks. One of the main consequences is
the possibility of ultra-heavy neutron stars, i.e.~stars with masses
significantly heavier than two solar masses. These stars pass all observational
and theoretical constraints, including those imposed by recent LIGO/Virgo
gravitational-wave observations and NICER X-ray observations. We thoroughly
investigate other consequences of this structure in the speed of sound to
develop an understanding of how non-smooth features affect astrophysical
observables, such as stellar radii, tidal deformability, moment of inertia, and
Love number. Our results have important implications to future gravitational
wave and X-ray observations of neutron stars and their impact in nuclear
astrophysics.

34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs