A5091290790- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Nuclear physics research studies
- High-pressure geophysics and materials
- Astro and Planetary Science
- Quantum Chromodynamics and Particle Interactions
- Solar and Space Plasma Dynamics
- Atomic and Subatomic Physics Research
- Stellar, planetary, and galactic studies
- High-Energy Particle Collisions Research
- Quantum, superfluid, helium dynamics
- Nuclear Physics and Applications
- Geophysics and Sensor Technology
- earthquake and tectonic studies
- Astrophysical Phenomena and Observations
- Neutrino Physics Research
- Superconducting Materials and Applications
- Advanced NMR Techniques and Applications
- Inertial Sensor and Navigation
- Astronomical and nuclear sciences
- Particle accelerators and beam dynamics
- Planetary Science and Exploration
- Geomagnetism and Paleomagnetism Studies
- Seismology and Earthquake Studies
Texas A&M University – Commerce
2014-2025
University of Oxford
2004-2008
The first results of a new three-dimensional, finite temperature Skyrme-Hartree-Fock$+$BCS study the properties inhomogeneous nuclear matter at densities and temperatures leading to transition uniform are presented. Calculations carried out in cubic box representing unit cell locally periodic structure matter. A constraint is placed on two independent components quadrupole moment neutron density investigate dependence total energy geometry cell. This approach allows self-consistent modeling...
We perform a systematic assessment of models for the equation state (EOS) dense matter in context recent neutron star mass and radius measurements to obtain broad picture structure stars. demonstrate that currently available provide strong constraints on moments inertia, tidal deformabilities, crust thicknesses. A measurement moment inertia PSR J0737-3039A with 10% error, without any other information from observations, will constrain EOS over range densities within 50%--60%. find...
Using a set of model equations state satisfying the latest constraints from both terrestrial nuclear experiments and astrophysical observations as well state-of-the-art many-body calculations pure neutron matter equation state, tidal polarizability canonical stars in coalescing binaries is found to be very sensitive probe high-density behavior symmetry energy which among most uncertain properties dense neutron-rich nucleonic matter. Moreover, it changes less than $\pm 10%$ by varying various...
The effects of the existence exotic nuclear shapes at bottom neutron star inner crust - `pasta' on observational phenomena are estimated by comparing limiting cases that those phases have a vanishing shear modulus and they crystalline solid . We estimate effect torsional crustal vibrations maximum quadrupole ellipticity sustainable crust. composition transition densities calculated consistently with global properties, using liquid drop model bulk equation state (EoS) which allows systematic...
The critical densities and impact of forming \D resonances in neutron stars are investigated within an extended nonlinear relativistic mean-field (RMF) model. for the formation four different charge states found to depend differently on separate kinetic potential parts nuclear symmetry energy, first example a microphysical property do so. Moreover, they sensitive in-medium Delta mass $m_{\Delta}$ completely unknown $\Delta$-$\rho$ coupling strength $g_{\rho\Delta}$. In universal baryon-meson...
The neutron-proton effective $k$-mass splitting in asymmetric nucleonic matter of isospin asymmetry $δ$ and normal density is found to be $m^{*}_{n-p}\equiv(m^{*}_{n}-m^{*}_{p})/m=(0.41 \pm0.15)δ$ from analyzing globally 1088 sets reaction angular differential cross sections proton elastic scattering on 130 targets with beam energies 0.783 MeV 200 MeV, 1161 data neutron 104 0.05 within an dependent non-relativistic optical potential model. It a useful reference for testing model predictions...
Much effort is devoted to measuring the nuclear symmetry energy through neutron star (NS) and observables. Since matter in NS core may be nonhadronic, observables like radii tidal deformability not provide reliable constraints on properties of nucleonic matter. By performing first consistent inference using ensembles crust equations state from astrophysical data, we demonstrate that coincident timing a resonant shattering flare (RSF) gravitational wave signal during binary inspiral probes...
The double pulsar J0737--3039 has become an important astrophysical laboratory for testing fundamental physics. Here we demonstrate that the low measured mass of Pulsar B can be used to constrain equation state neutron star matter {\em under assumption} it formed in electron-capture supernova. We show observed orbital parameters as well likely evolutionary history system support such a hypothesis and discuss future refinements will improve constraints this test may provide.
We study the nuclear symmetry energy S(rho) and related quantities of physics astrophysics predicted generically by relativistic mean-field (RMF) Skyrme-Hartree-Fock (SHF) models. establish a simple prescription for preparing equivalent RMF SHF parametrizations starting from minimal set empirical constraints on symmetric matter, binding charge radii, enforcing equivalence their Lorenz effective masses, then using pure neutron matter (PNM) equation state (EoS) obtained ab-initio calculations...
We present a systematic survey the range of predictions neutron star inner crust composition, crust-core transition densities and pressures, density nuclear `pasta' phases at bottom provided by compressible liquid drop model in light current experimental theoretical constraints on parameters. Using Skyrme-like for matter, we construct baseline sequences models consistently varying dependence bulk symmetry energy saturation density, $L$, under two conditions: (i) that magnitude $J$ is held...
Using a simple model of neutron star with perfectly rigid crust constructed and set core equations state that span the range nuclear experimental uncertainty in density dependence symmetry energy from 25 MeV (soft EOS) to 115 (stiff EOS), we calculate instability window for onset Chandrasekhar-Friedmann-Schutz (CFS) r-mode oscillations canonical stars (1.4 M_{\odot}) massive (2.0 M_{\odot}). In these models crust-core transition density, thus crustal thickness, is calculated consistently...
We present an inference of the nuclear symmetry energy magnitude $J$, slope $L$, and curvature ${K}_{\mathrm{sym}}$ from combining neutron skin data on calcium, lead tin isotopes, our best theoretical information about pure matter. A Bayesian framework is used to consistently incorporate prior knowledge matter equation state chiral effective field theory calculations. Neutron skins are modeled in a fully quantum Skyrme-Hartree-Fock approach using extended Skyrme energy-density functional...
There is a degeneracy between the equation of state (EOS) superdense neutron-rich nuclear matter and strong-field gravity in understanding properties neutron stars. While EOS still poorly known, there are also longstanding ambiguities choosing Einstein's general relativity (GR) or alternative theories not-so-well-tested regime. Besides possible appearance hyperons new phases, most uncertain part nucleonic currently density dependence symmetry energy especially at suprasaturation densities....
X-ray observations of the neutron star (NS) in Cas A supernova remnant over past decade suggest is undergoing a rapid drop surface temperature ≈2%–5.5%. One explanation suggests cooling triggered by onset superfluidity core star, causing enhanced neutrino emission from Cooper pair breaking and formation (PBF). Using consistent NS crust equations state (EOSs) compositions, we explore sensitivity this interpretation to density dependence symmetry energy L EOS used, presence bubble phases...
Abstract In this review article, we discuss selected developments regarding the role of equation state in simulations core-collapse supernovae. There are no first-principle calculations matter under supernova conditions since a wide range is covered, terms density, temperature, and isospin asymmetry. Instead, model commonly employed studies. These can be divided into regimes with intrinsically different degrees freedom: heavy nuclei at low temperatures, inhomogeneous nuclear where light...
ABSTRACT Resonant shattering flares (RSFs) are bursts of gamma-rays expected to be triggered by tidal resonance a neutron star (NS) during binary inspiral. They strongly dependent on the magnetic field strength at surface NS. By modelling these as being result multiple colliding relativistic shells launched window, we find that prompt non-thermal gamma-ray emission may have luminosity up few $\times 10^{48}\rm{ erg\,s}^{-1}$, and broad-band afterglow could produced. We compute rates...
Nuclear pasta is an exotic form of nuclear matter that occurs in the crust neutron stars below saturation density. Various structures with cylindrical, planar, and more complicated geometries evolve from Coulomb lattice nuclei immersed a fluid neutrons. Such should not only affect how star cools rotates but also height ``mountains'' can sustain---potentially detectable as persistent sources gravitational waves. By performing large set quantum calculations authors show energy landscape...
Chiral effective field theory (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mi>χ</a:mi><a:mi>EFT</a:mi></a:mrow></a:math>) has proved to be a powerful microscopic framework for predicting the properties of neutron-rich nuclear matter with quantified theoretical uncertainties up about twice saturation density. Tests <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mrow><b:mi>χ</b:mi><b:mi>EFT</b:mi></b:mrow></b:math> predictions are typically performed at low...
We show that the gravitational binding energy of a neutron star given mass is correlated with slope nuclear symmetry at 1-2 times saturation density for equations state without significant softening (i.e., those predict maximum masses $M_{\rm max} > 1.44M_{\odot}$ in line largest accurately measured mass). Applying recent laboratory constraints on to this correlation we extract constraint baryon lower member double pulsar binary system, PSR J0737-3039B. compare independent derived from...
We demonstrate that observations of glitches in the Vela pulsar can be used to investigate strength crust–core coupling a neutron star and provide powerful probe internal structure stars. assume glitch recovery is dominated by torque exerted mutual friction-mediated recoupling superfluid components core were decoupled from crust during glitch. Then we use recoveries two recent infer fraction coupled then analyse whether crustal neutrons alone are sufficient drive pulsar, taking into account...
The behaviour of the nuclear symmetry energy near saturation density is important for our understanding dense matter. This dependence can be parameterised by and its derivatives evaluated at density. In this work we show that core-crust interface mode a neutron star sensitive to these parameters, through (density-weighted) shear-speed within crust, which in turn dependent on profile We calculate frequency quadrupole ($\ell = 2$) crust-core must driven tidal field binary partner trigger...
ABSTRACT With current and planned gravitational-wave (GW) observing runs, coincident multimessenger timing of resonant shattering flares (RSFs) GWs may soon allow for neutron star (NS) asteroseismology to be used constrain the nuclear symmetry energy, an important property fundamental physics that influences composition equation state NSs. In this work, we examine effects combining multiple RSF detections on these energy constraints, consider how realistic uncertainties in masses progenitor...