Speaker
Description
Neutron stars are laboratories for the properties of
supra-dense matter and large isospin asymmetries, requiring expertise
from nuclear physics, particle physics, and astrophysics. Terrestrial
experiments are complementary since they probe the properties of
supra-dense matter close to nuclear saturation density (the average
density of atomic nuclei), or above but remaining close to isospin
symmetry. Since it connects isospin symmetric matter from terrestrial
experiments to neutron-rich matter in neutron stars, the symmetry energy
is instrumental. In this talk, I will present a theoretical approach
that can be employed to describe the properties of atomic nuclei and the
astrophysical observations, e.g., gravitational waves (LVK) and x-ray
emission from multi-second pulsars (NICER).
The impact of the symmetry energy on compact stars' properties is then
analyzed considering constraints from nuclear physics and astrophysics.
A compact star can be a neutron star composed only of nuclear matter or
a hybrid star with a quark core. Two typical models (soft and stiff) are
considered for the nuclear equation of state, and for the hybrid's one,
a parameterized first-order phase transition approach, completed with a
linear quark matter equation of state, is implemented.
In this talk, I will show that the phase transition reduces the tension
between GW170817 and NICER observations, and I will illustrate the
impact of the symmetry energy for the understanding of the nature of the
binary system in GW170817, confirming previous findings that the
GW170817 waveform is best described as a binary HS with stiff quark
matter at low density. This could also mark the presence of a quarkyonic
cross-over.
| Presentation Style | Invited Speaker |
|---|