Related papers: Constraining the Neutron Star Mass--Radius Relatio…
Pulse profile modelling (PPM) is a technique for inferring mass, radius and hotspot properties of millisecond pulsars. PPM is now regularly used for analysis of rotation-powered millisecond pulsars (RMPs) with data from the Neutron Star…
NICER has observed a few millisecond pulsars where the geometry of the X-ray emitting hotspots on the neutron star is analyzed in order to constrain the mass and radius from X-ray light curve modeling. One example, PSR J0030+0451, is shown…
We present a reanalysis of NICER observations of PSR J0740+6620 and PSR J0030+0451 to test the consistency of various nuclear equations of state (EoS) within the framework of hybrid star models. In particular, we examine how different…
We report the detection of 376.05 Hz (2.66 ms) coherent X-ray pulsations in NICER observations of a transient outburst of the low-mass X-ray binary IGR J17494-3030 in 2020 October/November. The system is an accreting millisecond X-ray…
Recently, the radius of neutron star (NS) PSR J0740+6620 was measured by Neutron Star Interior Composition Explorer (NICER) and an updated measurement of neutron skin thickness of ${}^{208}$Pb ($R_{\rm skin}^{208}$) was reported by the…
We demonstrate that future radius measurement of the NICER mission have the potential to reveal the existence of a strong phase transition in dense neutron star matter by confirming the existence of so called twin stars, compact star…
We report on the discovery by the Nuclear Spectroscopic Telescope Array (NuSTAR) and the Neutron Star Interior Composition Explorer (NICER) of the accreting millisecond X-ray pulsar IGR J17591-2342, detecting coherent X-ray pulsations…
Neutron stars exhibit magnetic fields and densities far beyond those achievable in terrestrial laboratories, offering a natural probe of strongly interacting matter under extreme conditions. Using observationally anchored mass-radius…
Recent NICER observation data on PSR J0030+0451 has recently added a unique mass-radius constraint on the properties of the superdense nuclear matter existing in the interior of compact stars. Such a macroscopic data restrict further the…
Recent modeling of Neutron Star Interior Composition Explorer(NICER) observations of the millisecond pulsar PSR J0030+0451 suggests that the magnetic field of the pulsar is non-dipolar. We construct a magnetic field configuration where foot…
Thermally emitting X-ray isolated neutron stars represent excellent targets for testing cooling surface emission and atmosphere models, which are used to infer physical parameters of the neutron star. Among the seven known members of this…
We present a new numerical algorithm for the calculation of pulse profiles from spinning neutron stars in the Hartle-Thorne approximation. Our approach allows us to formally take into account the effects of Doppler shifts and aberration, of…
We present the results obtained from the spectral and temporal study of thermonuclear bursts from the millisecond X-ray pulsar SRGA J144459.2-604207 detected with NICER. The dynamic evolution of the spectral parameters in a broad energy…
The Neutron Star Interior Composition Explorer (NICER) recently measured the mass and equatorial radius of the isolated neutron star PSR J0030+0451. We use these measurements to infer the moment of inertia, the quadrupole moment, and the…
The accretion-powered (non-X-ray burst) pulsations of XTE J1814-338 are modeled to determine neutron star parameters and their uncertainties. The model is a rotating circular hot spot and includes: (1) an isotropic blackbody spectral…
We search for possible correlations between neutron star observables and thermodynamic quantities that characterize high density nuclear matter. We generate a set of model-independent equations of state describing stellar matter from a…
The nuclear matter equation of state is relatively well constrained at sub-saturation densities thanks to the knowledge from nuclear physics. However, studying its behavior at supra-saturation densities is a challenging task. Fortunately,…
Equilibrium sequences were developed for rotating NS in the relativistic mean-field interaction framework using four density-dependent equations of state for the NS matter. These sequences were constructed for the observed rotation…
We investigate the nuclear symmetry energy and neutron star properties using a Bayesian analysis based on constraints from different chiral effective field theory calculations using new energy density functionals that allow for large…
The inner structure of neutron star is considered from theoretical point of view and is compared with the observed data. We have proposed a form of an equation of state relating pressure with matter density which indicates the stiff…