The cores of neutron stars contain matter at densities and neutron-proton asymmetries that are inaccessible in laboratories. Thus astronomical observations of neutron stars are the only source of information we have about this state of matter, which is a key part of the QCD phase diagram. One of the most important such measurements is of the mass and radius of these stars. Recently, NASA's...
This talk will review the effect that superconductivity has on a neutron star's magnetic field and its evolution. We will discuss some of the many open issues and uncertainties, and possible ways future observations may help reduce our collective ignorance.
The coupled evolution of magnetism and temperature inside neutron stars has a direct imprint on the rotational and spectral properties observed in their population. These different manifestations of isolated neutron stars can be unified under an evolutionary scenario where the magnetic field and its long-term evolution plays a key role in shaping the X-ray detectability. In addition, the...
Multi-wavelength observations over the last decades proved the existence of observationally very diverse manifestations of isolated NSs (INSs): radio-pulsars, Magnetars, X-ray Dim INSs (XDINSs), high-B rotation powered pulsars, Rotating radio transients (RraTs) , and Central Compact Objects (CCOs). Among them magnetars and XDINSs are the most highly magnetized NSs and they also represent key...
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The origin of the pulsed high-energy emission in pulsars is an outstanding open question since the early days of gamma-ray astronomy. Today, the combination of sensitive observations in the GeV domain and increasingly sophisticated numerical simulations have recently brought new insights into our understanding of the pulsed emission and particle acceleration processes in pulsars. I will review...
When residing in an X-ray binary, a neutron star accretes gas from a companion star. As matter accumulates on the neutron star surface, the underlying crust is compressed and heated due to nuclear reactions induced by this compression. These heating processes play an important role in setting the observable properties of thermonuclear bursts and rapid variability (mHz QPOs) observed from...
Thermal evolution of neutron stars in soft X-ray transients (SXTs) is sensitive to neutron-star equation of state (EoS), neutrino emission rates, and structure of the neutron-star crust. Therefore, comparison of observations of quiescent thermal emission of SXTs with numerical simulations of their heating and cooling is useful for verification of theoretical models of the dense matter in...
Observing binary neutron star mergers with gravitational-wave observatories allows for new constraints to be set on the properties of high-density matter in the core of neutron stars. I will discuss an absolute constraint on the minimum radius of neutron stars, based on source characteristics derived by the GW170817 event and on a minimal set of assumptions. Upgraded or third-generation...
Compact binary mergers are multi-dimensional, multi-physics, multi-scale phenomena that possibly produce a large variety of signals, including gravitational, electromagnetic and neutrino radiations. Moreover, they are major sites for the synthesis of heavy elements through the so called r-process nucleosynthesis. The outcome and the observables associated to these events have a non-trivial...
The discovery of the gravitational wave transient GW170817 and its electromagnetic counterparts ushered in a new era of multi-messenger. astrophysics, in which both gravitational waves and light provide complementary views of the same source. These observations gave astronomers an unprecedented opportunity to probe the merger of two neutron stars, solving decade-long mysteries about the origin...
Over 50 years of pulsar observations has proven that understanding the structure of pulsars magnetospheres and the exotic processes taking in it is difficult. This includes the lack of understanding of how they generate radio emission. Nevertheless, radio observations provides a wealth of information related to variability, polarization and their spectral dependence. Important lessons can be...
The observational evidence for superfluidity in neutron stars will be reviewed. Rotational and
magnetic properties of superfluids and superconductors will be discussed, to lead to the
current understanding of neutron star dynamics. In particular pulsar glitches and interglitch
relaxation will be addressed in terms of superfluid vortex pinning, unpinning and creep.
Extraction of information...
Timing of neutron stars leads to information about their energy losses, magnetic field and internal dynamics including superfluid phenomena. In young pulsars, the long-term evolution of the spin-down rate can often be probed, in addition to irregularities such as timing noise and spin-up glitches. We will review the main observational attributes of their rotation and discuss some of the most...
In 2016, Parfreyman et al obtained exquisitely detailed observations of Vela during the epoch of one of its large glitches. One remarkable feature was a clear observation of a short-lived magnetospheric disturbance. I will advance a theory for the disturbance and discuss its implications for the physics of glitches.
FRBs are currently one of the biggest unsolved and most tantalizing enigmas of astrophysics. They manifest themselves as millisecond duration pulses at cosmological distances. Over 100 FRBs have been discovered to date with a remarkable diversity of observed properties, but no consensus has emerged regarding the nature of their progenitor(s). Almost every radio telescope in the world is...
A good knowledge of the neutron star population of the Universe has important implications for our understanding of the sources that may be detected as gravitational wave emitters, gamma ray bursts, and FRBs, to name a few. It has been highlighted in the past that the current rate of core-collapsed supernovae is not large enough to explain the combined birth rates of various types of neutron...
The equation of state (EoS) of dense hadronic matter is of crucial importance for the description of the static and dynamical properties of neutron stars. In this talk I will review the current status of the hadronic EoS for neutron stars, from the point of both ab-initio many-body approaches and phenomenological models, paying a special attention to recent mean-field phenomenological...
Resonant Shattering Flares (RSFs) are expected to occur during the inspiral phase for some NS-NS and NS-BH mergers. They result from the resonant tidal excitation of the NS crust-coreinterface mode fracturing the crust and sparking a relativistic pair-photon fireball, emitted seconds before the merger.
RSFs are prompt, bright, and isotropic, allowing potential detection and triggering from...