Related papers: Neutron Dark Decay and Exotic Compact Objects
The recent precise measurement of the mass of pulsar PSR J1614$-$2230, as well as observational indications of even more massive neutron stars, has revived the question of the composition of matter at the high densities prevailing inside…
IGR J18214-1318, a Galactic source discovered by the International Gamma-Ray Astrophysics Laboratory, is a high-mass X-ray binary (HMXB) with a supergiant O-type stellar donor. We report on the XMM-Newton and NuSTAR observations that were…
The trace anomaly $\Delta$ is an important quantity that measures the broken conformal symmetry in neutron star matter. In this work, we present quasi-universal relations that connect the stellar profile of $\Delta$ to the compactness,…
The possible signatures of the presence of hyperons inside neutron stars are discussed within a Bayesian inference framework applied to a set of models based on a density-dependent relativistic mean-field description of hadronic matter.…
We report on a series of spectroscopic observations of PSR J1311-3430, an extreme black-widow gamma-ray pulsar with a helium-star companion. In a previous study we estimated the neutron star mass as M_NS= 2.68+/-0.14M_Sun (statistical…
The mirror twin Higgs model is a candidate for (strongly-interacting) complex dark matter, which mirrors SM interactions with heavier quark masses. A consequence of this model are mirror neutron stars -- exotic stars made entirely of mirror…
It has been suggested for a long time that dark matter would form a density spike around a black hole. However, no promising evidence has been observed so far to verify this theoretical suggestion. Here, we report the existence of a dark…
With central densities way above the density of atomic nuclei, neutron stars contain matter in one of the densest forms found in the universe. Depending of the density reached in the cores of neutron stars, they may contain stable phases of…
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…
Bursting X-ray binaries in globular clusters are ideal sources for measuring neutron star masses and radii, and hence, for determining the equation of state of cold, ultradense matter. We use time-resolved spectroscopic data from EXO…
Within the parameter space of equation of state (EOS) of dense neutron-rich matter limited by existing constraints mainly from terrestrial nuclear experiments, we investigate how the neutron star maximum mass $M_{\rm{max}}>2.01\pm0.04$…
The recent measurements of the masses of the pulsars PSR J1614-2230 and PSR J0348-0432 provide independent proof for the existence of neutron stars with masses in range of 2 $M_\odot$. This fact has significant implications for the physics…
The nearby isolated neutron stars are a group of seven relatively slowly rotating neutron stars that show thermal X-ray spectra, most with broad absorption features. They are interesting both because they may allow one to determine…
Inspired by the well known anomaly in the life time of the neutron, we investigate its consequences inside neutron stars. We first assess the viability of the neutron decay hypothesis suggested by Fornal and Grinstein within neutrons tars,…
Neutrons stars are unique laboratories to discriminate between the various proposed equations of state of matter at and above nuclear density. One sub-class of neutron stars - those inside quiescent low-mass X-ray binaries (qLMXBs) -…
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…
We report on observations of the neutron star (NS) residing in the low-mass X-ray binary 1RXS J180408.9-34205 taken 2015 March by $\emph{NuSTAR}$ and $\emph{XMM-Newton}$ while the source was in the hard spectral state. We find multiple…
We discuss the impact of strange hadrons, in particular hyperons, on the gross features of compact stars and on core-collapse supernovae. Hyperons are likely to be the first exotic species which appears around twice normal nuclear matter…
The core of neutron-star matter is supposed to be at a much higher density than the normal nuclear matter density for which various possibilities have been suggested such as, for example, meson or hyperon condensation and/or deconfined…
Recent rapid progress in neutron-star (NS) observations offers great potential to constrain the properties of strongly interacting matter under the most extreme conditions. In order to fully exploit the current observational inputs and to…