Conveners
Dense Matter in Compact Stars: Block 1
- Jorge Armando Rueda Hernandez (ICRANet)
- Alessandro Drago (University of Ferrara)
Dense Matter in Compact Stars: Block 2
- Alessandro Drago (University of Ferrara)
- Jorge Armando Rueda Hernandez (ICRANet)
Description
This session is devoted to reporting advances in the theoretical understanding of microphysics (equation of state, particle composition, etc) and macrophysical structure of high-dense compact stars such as neutron stars, hybrid stars, and quark stars. In recent years, multimessenger observations of these compact stars in binaries as well as isolated, e.g. in the X-rays (e.g. NICER, HXMT, XMM-Newton, Chandra, Swift), gamma-rays (e.g. Fermi), and radio facilities, together with synergic analyses of gravitational waves, neutrinos, and dark matter have given rise to new observational windows and constraints on compact stars' structure on which this session welcomes discussions, including perspectives from forthcoming experimental facilities.
Rotational irregularities in neutron stars, principally glitches and timing noise, are often regarded as nuisance phenomena which are subtracted from electromagnetic pulsar timing data in order to reveal the underlying, secular rotational evolution. This represents a missed opportunity. Glitches and timing noise excite internal degrees of freedom in the star impulsively and stochastically. The...
Timing noise in a pulsar is the stochastic deviation of the pulse arrival times of the pulsar away from its long term spin down trend. In the classic two-component neutron star model, interactions between the crust and superfluid cause these perturbations to decay exponentially with a characteristic timescale. This research uses a Kalman filter to track the pulsar frequency through time and to...
We investigate the properties of anisotropic, spherically symmetric compact stars, especially neutron stars and strange quark stars, made of strongly magnetized matter. The neutron stars are described by a polytropic equation of state, the strange quark stars by an equation of state based on the MIT Bag model. The stellar models are based on an a priori assumed density dependence of the...
Neutron stars (NSs) harbour extremely powerful magnetic fields, leading to their shape being deformed. The magnetic deformation of NSs depends both on the geometry - and strength - of their internal magnetic field and on their composition, encoded by the equation of state (EoS). However, both the details of the internal magnetic structure and the EoS of the innermost part of NSs are mostly...
Gravitational waves from the late inspiral, merger, and post-merger of a binary neutron star coalescence provide complementary information about the cold and hot equations of state of neutron star matter. These signals dominate in the kHz range, higher than the most sensitive part of the current generation of gravitational-wave interferometers. I will present the design concept and science...
The composition of neutron stars is an open research problem. In particular, the lack of information on the behavior of the symmetry energy above saturation density has prevented a reliable first-principle calculation of neutron stars equation of state. However, recently, new observational data has become available, which allows for better constraining of the internal properties of the star,...
PSR J0537-6910 is a young neutron star that regularly experiences pulsar glitches, and shows a rather high braking rate between them. Observed spin-down of the pulsar could be due to the r-mode oscillations, which in turn may generate gravitational waves in the sensitivity range of the LIGO and Virgo detectors.
Based on the analysis of the LIGO-Virgo-KAGRA observing run O3, and taking into...
Gravitational wave astronomy is expected to provide independent constraints on neutron star properties, such as their equation of state. This is possible with the measurements of binary components' tidal deformability, which alter the point-particle gravitational waveforms of neutron-star binaries. I'll discuss some tidal deformability effects due to the elasticity/solidity of the hadronic...
We calculate the elastic properties of the outer crust of Neutron Stars (NSs) under the approximation of the one component plasma (OCP) in the high density limit. An electron sector under a degenerate Fermi sea is considered. This is of interest for the modelling of the gravitational wave signal strength emitted in the violent events of NS mergers and NS continuous emission. We use Molecular...
Neutron star observations offer us an excellent testbed to measure nuclear parameters that are difficult to access with terrestrial experiments. Some of these nuclear parameters have strong correlations with radii and tidal deformabilities of neutron stars. In this talk, I focus on one of such parameters, K_{sym,0}, that corresponds to the curvature of symmetry energy at nuclear saturation...
After three decades, the neutron star formed by SN 1987A has likely given us a first sign of its presence: a blob of warm dust near the center of the explosion. I will summarize our understanding of the explosion, the structure of the supernova remnant, and the characteristics of "the blob”. I will describe in detail the possible explanations for the excess of energy coming out of the blob:...
The gravitational waves event GW190814 originated from the merger of a 23Msun black – hole and a compact object of 2.6 Msun. The nature of the low mass companion is quite puzzling since it could be either the lightest black -hole or the heaviest neutron star ever known. In particular, if such massive neutron stars do exist, it seems to be difficult to reconcile the indications from data...
With recent observations of gravitational wave signals from binary neutron star(BNS) mergers and observations by NICER, the nuclear equation of state(EoS) is becoming increasingly testable by numerical simulations. Numerous simulations currently exist exploring the equations of state at different density regimes for the constituent neutron stars. In this work we perform full GR...
A hybrid star consisting of a defined quark matter core and a hadronic matter envelope has a unique internal structure that can have some influence on its observable properties. One possibility is the tidal effect during binary compact star coalescence, which is encoded in the phase of the emitted gravitational wave signal. In particular, the dynamical part of the tide which comes from the...
Hypermassive hybrid stars (HMHS) are extreme astrophysical objects that could be produced in the merger of a binary system of two neutron stars. In contrast to their purely hadronic counterparts, hypermassive neutron stars (HMNS), these highly differentially rotating objects contain deconfined strange quark matter in their slowly rotating inner region. HMHS and HMNS are both metastable...
The equation of state (EoS) of matter at supranuclear densities in the core of neutron stars (NSs) contains key information on the properties of the strong force and the possible existence of exotic states of matter; however it is only poorly constrained from earth-based experiments and theory. NS properties, the precise values of M and R in particular, encode unique information on the EoS,...
Compact astrophysical objects such as neutron stars (NSs) offer natural laboratories that can accrete sizable amount of Dark Matter (DM) in extreme density regimes. In this work, we study the presence of self-interacting bosonic DM in NSs through its effect on various properties of NSs. In our scenario, the bosonic DM and baryonic matter (BM) are mixed together which are interacting only...
