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short gamma-ray bursts (sgrbs) are generally thought to result from the merger of two neutron stars or the merger of a neutron star with a black hole. it is becoming standard practice to model these mergers with hydrodynamical simulations that employ equations of state that are derived, for example, for determining the... | short gamma-ray bursts and the decompression of neutron star matter in tidal streams |
recent research on the classical pulsar b0950+08 demonstrates that the explanation of its high surface temperature by roto-chemical heating encounters some difficulties. we assume that there is a fall-back disc around the newborn neutron star, which originates from the supernova ejecta and influences the spin and magne... | roto-chemical heating in a neutron star with fall-back disc accretion |
black hole-torus systems from compact binary mergers are possible engines for gamma-ray bursts (grbs). during the early evolution of the post-merger remnant, the state of the torus is determined by a combination of neutrino cooling and magnetically-driven heating processes, so realistic models must include both effects... | evolution of the magnetized, neutrino-cooled accretion disk in the aftermath of a black hole neutron star binary merger |
accreting neutron stars host a number of astronomical observables which can be used to infer the properties of the underlying dense matter. these observables are sensitive to the heating and cooling processes taking place in the accreted neutron star (ns) crust. within the past few years it has become apparent that ele... | the great wall: urca cooling layers in the accreted ns crust |
pulsed non-thermal quiescent emission between 10 kev and around 150 kev has been observed in $\sim10$ magnetars. for inner magnetospheric models of such hard x-ray signals, resonant compton upscattering of soft thermal photons from the neutron star surface is the most efficient radiative process. we present angle-depen... | magnetar hard spectral tails |
pairing gaps in neutron matter need to be computed in a wide range of densities to address open questions in neutron star phenomenology. traditionally, the bardeen-cooper-schrieffer approach has been used to compute gaps from bare nucleon-nucleon interactions. here, we incorporate the influence of short- and long-range... | beyond bcs pairing in high-density neutron matter |
the role of magnetic field decay in normal radio pulsars is still debated. in this paper, we present results which demonstrate that an episode of magnetic field decay in hot young neutron stars can explain anomalous values of braking indices recently measured for more than a dozen of sources. it is enough to have few t... | magnetic field decay in young radio pulsars |
the accretion behaviour in low-mass x-ray binaries (lmxbs) at low luminosities, especially at <e34 erg/s, is not well known. this is an important regime to study to obtain a complete understanding of the accretion process in lmxbs, and to determine if systems that host neutron stars with accretion-heated crusts can ... | erratum: uv and x-ray observations of the neutron star lmxb exo 0748-676 in its quiescent state |
two serious problems caused by a hyperon (y)-mixing in neutron stars (nss), (i) too-soft eos incompatible with 2m ⊙ -ns observations and (ii) too-rapid cooling inconsistent with surface temperature observations, are discussed. with a brief review as to the works to solve (i), it is stressed that the universal 3-body fo... | hyperon mixing and two serious problems in neutron stars |
11 of the gogny forces available in literature have been studied in order to evaluate their isovector properties and to comment on their viability for beyond 1s0 pairing channels, and neutron star cooling calculations. i find that, even within a relatively narrow set of gogny functionals, there is a large variation in ... | isovector and pairing properties of the gogny interaction in the context of neutron stars. |
with the observations from rossi x-ray timing explorer, we search and study the x-ray bursts of accreting millisecond x-ray pulsar sax j1748.9-2021 during its 2010 outburst. we find 13 x-ray bursts, including 12 standard type-i x-ray bursts and an irregular x-ray burst which lacks cooling tail. during the outburst, the... | the x-ray bursts within the 2010 outburst of the accreting millisecond x-ray pulsar sax j1748.9-2021 |
context. the recent discovery of long-period, low magnetic field pulsars in low-mass x-ray binaries (lmxbs) represents a challenge for the standard evolutionary scenario. these pulsars have a magnetic field strength comparable to that of millisecond pulsars (~108-109 g), but their period is at least an order of magnitu... | igr j17480-2446: a new class of accreting binaries? |
the binary neutron star (bns) merger event gw170817, followed by a low luminosity burst of γ-rays and an exceptional broadband afterglow with late onset and early brightening, has raised a heated debate concerning the post-merger outflow structure: a mildly relativistic quasi-spherical outflow or a relativistic structu... | investigating outflow structures of gamma-ray bursts |
we have studied shock in magnetized accretion flow/funnel flow in case of neutron star with bremsstrahlung cooling and cyclotron cooling. all accretion solutions terminate with a shock close to the neutron star surface, but at some regions of the parameter space, it also harbours a second shock away from the star surfa... | study of magnetized accretion flow with cooling processes |
by the relativistic mean field theory and relevant weak-interactional cooling theory, the relativistic cooling properties in the conventional and hyperonic neutron star matter are studied. also a comparison between the relativistic and non-relativistic results after taking consideration of the gravity correction is per... | relativistic correction of neutrino emission in neutron stars |
we show a scenario for the cooling of compact stars considering the central source of cassiopeia a (cas a).the cas a observation shows that the central source is a compact star with a high effective temperature, and it is consistent with the cooling without exotic phases. the cas a observation also gives the mass range... | cooling of compact stars with color superconducting quark matter |
the recent measurements of the masses of the pulsar j00737-3039b and of the companion j1756-2251 and pulsars psr j1614-2230, psr j0348-0432 demonstrate the existence of compact stars with masses in a broad range from 1.2 to 2 $m_\odot$. to fulfill the constraint $m_{\rm max}>2m_{\odot}$ and to demonstrate the possib... | proton gaps and cooling of neutron stars with a stiff hadronic eos |
in this work we consider the effect that the appearance of pseudoscalar condensates in a neutron star can have on its cooling rate. we make no particular assumption on the origin and characteristics of these possible condensates and only assume that in regions where the pseudoscalar density varies the propagation of ph... | effects of pseudoscalar condensation on the cooling of neutron stars |
we model the pulse profiles and the phase-resolved spectra of the anomalous x-ray pulsar 1e 1048.1-5937 obtained with xmm-newton to map its surface temperature distribution during an active and a quiescent epoch. we develop and apply a model that takes into account the relevant physical and geometrical effects on the n... | mapping the surface of the magnetar 1e 1048.1-5937 in outburst and quiescence through phase-resolved x-ray spectroscopy |
the galactic bulge survey (gbs) is a broad, shallow survey of bulge x-ray sources with extensive multiwavelength support. the limiting sensitivity, about 2×1032 erg/s at the bulge distance, is well suited to finding symbiotic x-ray binaries (syxbs) containing neutron stars accreting from a cool giant wind, as well as x... | x-ray selected symbiotic candidates in the galactic bulge survey |
the neutron capture cross section of several key unstable isotopes acting as branching points in the s-process are crucial for stellar nucleosynthesis studies, but they are very challenging to measure due to the difficult production of sufficient sample material, the high activity of the resulting samples, and the actu... | neutron capture cross sections of the s-process branching points 147pm, 171tm, and 204tl |
considering the baryon octet in the framework of relativistic mean field (rmf) theory, and the entropy per baryon is selected to be 1 or 2, we investigate the entropy effect on the protostar properties of the massive neutron star psr j0348+0432. one set of coupling constants gl85 in the rmf are selected to reproduce th... | composition and structure of massive protoneutron star of psr j0348+0432 |
nuclear mass measurement has maintained an important position in the field of nuclear physics for a little over a century. nuclear masses provide key evidence of the structural transformation of nuclei away from the valley of beta-stability and are essential input for many simulations of extreme astrophysical environme... | extension of the nuclear mass surface for neutron-rich isotopes of argon through iron |
neutrino production is the dominant cooling process in neutron stars. after the rapid cooling during the protoneutron star stage, the neutron star crust is formed. neutrinos continue to be produced in the crust, which can escape from the surface. this neutrino production is an important process to the final cooling pha... | neutrino emission from neutron star crusts |
nuclear burning near the surface of an accreting neutron star produces ashes that, when compressed deeper by further accretion, alter the star's thermal and compositional structure. bygone nucleosynthesis can be constrained by the impact of compressed ashes on the thermal relaxation of quiescent neutron star transients... | constraints on bygone neutron star nucleosynthesis using urca coolers in the crust |
fission fragments emitted in a fissile solution create tiny gas bubbles, the size of which is determined by the linear energy transfer (let) of the particles. the let of fission fragments of 235u in aqueous solutions of uranyl nitrate has been determined, and using methods adapted from the literature, the size of gas b... | linear energy transfer of fission fragments of 235u and nucleation of gas bubbles in aqueous solutions of uranyl nitrate |
a detailed study of magnetized astrophysical flows has been carried out in the magnetohydrodynamic and special relativistic magneto- hydrodynamic regime. we have considered the thermodynamics of the flow to be described with a fixed as well as, a variable adiabatic index equation of state (eos). as examples of mhd flow... | the study of astrophysical magnetized flows |
after a period of active accretion, neutron stars can enter a phase where their x-ray emission is dominated by thermal emission from their surface. the rate of cooling of this emission can yield insight into neutron star structure. furthermore, emission models may help determine the neutron star radius. a number of que... | the quiescent neutron star and hierarchical triple: 4u 2129+47 |
we use the smoothed particle hydrodynamics (sph) method to simulate the behavior of inviscid flow accreting on a neutron star. for black holes, the lack of any hard surface allows matter to advect in supersonically. for neutron stars, however, the presence of a hard surface requires matter to settle down on the surface... | formation and stability of oscillating shocks in inviscid advective flows around neutron stars in presence of cooling using smoothed particle hydrodynamic simulations |
a multispecies hydrodynamic model based on moments of the born-bogolyubov-green-kirkwood-yvon (bbgky) hierarchy is developed for physical conditions relevant to astrophysical plasmas. the modified transport equations incorporate strong correlations through a density functional theory closure, while fluctuations enters ... | diffusive mixing in strongly coupled plasmas |
the effective λ -λ interaction energies in s-shell double-λ hypernuclei, λλ6he , λλ5he and λλ5h have been investigated by solving three-body system (λ + λ + core) within the framework of coupled rearrangement channel gaussian basis treatment. the nijmegen soft-core potential models, nsc97d, nsc97e and nsc97f, have been... | medium effect in s-shell double-λ hypernuclei and hyperon superfluidity in neutron star cores |
i will present a new general relativistic magnetohydrodynamic (grmhd) code devoted to the study of compact binary mergers with finite temperature equations of state and neutrino emission. numerical modeling of neutron stars binaries, black holes binaries, and neutron star-black hole binaries has now become one of the m... | spritz: a new fully general relativistic magnetohydrodynamic code |
most neutron stars cool predominately via the modified urca process, in which emitted neutrinos carry away energy. the traditional treatment for the in-medium nucleon propagator in the modified urca process uses crude approximations. we reformulate the propagator by including the nucleon self-energy and examine the eff... | improved treatment of neutron star cooling via modified urca process |
accreting neutron stars (ns) can exhibit high-frequency modulations in their lightcurves during thermonuclear x-ray bursts, known as burst oscillations. their frequencies can be offset from the spin frequency of the ns by several hz (known independently), and can drift by 1-3 hz. new x-ray missions with improved sensit... | new burning physics and burst oscillations |
using a model for the equation of state and composition of dense matter and the magnitude of singlet proton superconductivity and triplet neutron superfluidity, we perform the first simultaneous fit of neutron star masses and radii with neutron star luminosities and ages determined from observations of isolated neutron... | multi-messenger neutron star astrophysics and determining the composition of the neutron star core |
we show a cooling scenario of compact stars to satisfy recent observations of compact stars. the central density of compact stars can exceed the nuclear density, and it is considered that many hadronic phases appear at such a density. it is discussed that neutron superfluidity (1s0 for lower density, and 3p2 for higher... | cooling of compact stars with nucleon superfluidity and quark superconductivity |
x-ray burst oscillations are coherent signals which are detected in neutron star low-mass x-ray binaries during their type-i x-ray bursts. the frequency of x-ray burst oscillation is close to the neutron star spin rate. in recent years, about 30 neutron star low-mass x-ray binaries have been detected x-ray burst oscill... | research progress of x-ray burst oscillation |
axions are a generic expectation in many extensions of the standard model. neutron stars have long been a stringent probe of axions through observations of their cooling. axions can be created within the hot core of the neutron star and escape the star due to their weak interactions with matter. however, the emitted ax... | searching for axions with neutron stars |
type i x-ray bursts are thermonuclear explosions observed in many accreting neutron stars (nss) that result from rapid unstable burning of hydrogen and helium accreted onto the surface of the star. during an x-ray burst the x-ray flux rapidly rises by a factor of 10-20 in a couple of seconds and then decays on a longer... | fanning the flames: x-ray burst probes of nuclear burning |
we propose a 70 ks xmm-newton observation of the low-mass x-ray binary1rxs j180408.9-342058 in quiescence. continuing our study of how the crustof this neutron star cools after it was heated during a bright accretionoutburst in 2015, yields very valuable information about its structureand various processes occurring in... | the cooling crust of the neutron star in 1rxs j180408.9-342058 |
observing the cooling of neutron stars reheated by accretion providesunique insights into neutron-star structure. here we propose to continueour observations of the cooling neutron star in maxi j0556-332, atransient that had been accreting at near/super-eddington rates for16 months when it returned to quiescence in may... | cooling of the super-heated neutron star in maxi j0556-332 |
we study the neutrino anti-neutrino pair synchrotron emission from electrons and protons in a relativistic quantum approach. this process occurs only under a strong magnetic field, and it is considered to be one of effective processes for neutron star cooling. in this work we calculate the luminosity of the neutrino an... | \\nu \\bar{\\nu} -pair synchrotron emission in neutron-star matter based on a relativistic quantum approach |
we report our recent study of how neutron star spin rates may affect the stabilization of nuclear burning on the star's surface in low mass x-ray binaries. unstable burning can be triggered by the ignition of accumulated fuel from the donor, resulting in thermonuclear (type i) x-ray bursts. the burning will become stea... | the potentially rotational effect on the stabilization of thermonuclear burning of accreting neutron stars |
the disposal of residue forms an integral part of the alumina refining process. the refining of western australia bauxite, which is low grade ore by world standards, results in 2 dry tonnes of residue for every 1 tonne of alumina produced. the disposal of this residue contributes a significant proportion of the overall... | developments in the disposal of residue from the alumina refining industry |
observing x-rays during quiescence from transiently accreting neutron stars provide unique clues about the nature of dense matter. current models of neutron star crust, however, systematically predict lower temperatures than those observed, and an artificial shallow heat source is required to account for the observatio... | pycnonuclear fusion and the shallow heat source in accreting neutron star crusts |
it is very important to investigate the properties of the neutron superfluid that exists inside neutron stars. for example, it is known that the cooling curves of the stars strongly depend on the superfluid pairing gap. the theoretical study is very challenging due to the complexity of the physical system in such extre... | the superfluid pairing gap of a neutron star |
compact astrophysical sources like neutron stars and magnetars possess extremely strong magnetic fields. radiative cooling of plasma particles in their magnetospheres can be short compared to the plasma dynamical time. such magnetospheres are observed to produce strong flares, which indicates production of relativistic... | on motion of a particle in a strong-field magnetic bottle |
we propose joint chandra-vla-hst observations to continue our monitoring of the binary neutron star merger gw170817 at t~500-850 days since merger. our immediate objectives are: (i) to constrain the broad-band spectral evolution of the non-thermal emission from gw170817, and, in particular, the passage of the synchrotr... | late-time monitoring of gw170817 across the electromagnetic spectrum |
various telescopes including rxte, integral, suzaku, and fermi have detected steady non-thermal x-ray emission in the 10 - 200 kev band from strongly magnetic neutron stars known as magnetars. magnetic inverse compton scattering is believed to be the leading candidate for the production of this intense x-ray radiation.... | resonant compton physics for magnetar astrophysics |
the multi-wavelength study of >100 myr old radio-pulsars holds the key to understanding the long-term evolution of neutron stars, including the advanced stages of the surface cooling history, and possible variations in the magnetosphere properties. near-uv observations of neutron stars are particularly important for... | the old pulsar psr j0108-1431, a key target to understand the long-term evolution of neutron stars |
we present two recent parametrizations of the equation of state (fsu2r and fsu2h models) that reproduce the properties of nuclear matter and finite nuclei, fulfill constraints on high-density matter stemming from heavy-ion collisions, produce 2m⊙ neutron stars, and generate neutron star radii below 13 km. making use of... | the equation of state and cooling of hyperonic neutron stars |
we propose 6x30 ks observations of the radio/gamma-ray pulsar psr j2032+4127 and its companion be-star mt91 213. this nearby pulsar is in a 49 yr orbit and will reach periastron 2017 november 13, when it will undergo an outburst if it accretes from a disk that surrounds the be star. our proposed observations allow us t... | post-periastron behavior of psr j2032+4127/mt91 213: outburst, jet, and winds |
we propose to continue our highly successful coverage of the coolingneutron star in maxi j0556-332, which was strongly heated during anear/super-eddington outburst in 2011/12 and again during a smalleroutburst in 2016. our quiescent observations, which revealed anextraordinarily hot and rapidly cooling neutron star, ha... | cooling of the super-heated neutron star in maxi j0556-332 |
we propose to observe any be x-ray transient after its next type-iioutburst during a potential quasi-stable low-luminosity plateau phasethat has been identified in several sources. the origin of this plateauphase is still unclear and could be due to the cooling of an accretionheated neutron star crust or due to residua... | raiders of the low luminosity state in be x-ray transients |
we study the screening of a strong magnetic field operated by an initial huge number of e± pairs (we do not discuss here their production mechanism). the background fields configuration is of crossed fields, (b→ = bz^, e→ = ey^), with e/b < 1. in this system the following series of processes occur: 1) the electric f... | on the magnetic field screening in strong crossed electromagnetic field |
we reanalyse the x-ray spectrum of the psr b0833–45 (the vela pulsar) using the data of the chandra space observatory. in contrast to previous works, we consider a wide range of possible masses and radii of the pulsar. the derived surface temperature of the star ts∞=0.66‑0.01+0.04mk (1σ level over the entire mass and r... | thermal spectrum and neutrino cooling rate of the vela pulsar |
we use smoothed particle hydrodynamics (sph) technique to simulate the formation of two-component advective flow (tcaf) for accretion onto black holes and neutron stars in presence of cooling and viscous effects. we vary the accretion rates from sub-eddington to super-eddington for flows having different values of inje... | time-dependent numerical simulation of eddington and super-eddington accretion flows onto black holes and neutron stars using smoothed particle hydrodynamics |
we propose to continue our program to use the crust cooling behaviorin transiently accreting neutron stars. those crusts are heated due tothe matter accretion onto the neutron stars during outbursts. after theoutbursts are over the crusts cool down until they are in equilibrium withthe cores again. following this cooli... | crust cooling of accretion-heated neutron stars |
a significant fraction of young neutron stars can experience a strongfall-back episode after a supernova explosion. the accreted matter screensthe magnetic field which slowly diffuses out on a time scale of tens ofthousand years which is much shorter than the cooling timescale. however,no young radio pulsars with re-em... | probing magnetic field re-emergence through x-ray observations of radio pulsars |
in this work we determine the equation of state and the population of baryons and leptons and discuss the effects of the hyperon-meson coupling constants to the formation of delta resonances in the stellar medium. we also discuss the structure of the protoneutron stars including the delta matter in their composition, a... | hyperon-meson and delta-meson coupling to protoneutron stars structure using the nonlinear walecka model |
we are entering a new era when first-principles computational and theoretical studies of complex collective plasma processes under extreme conditions-marked by the importance of relativistic, radiation, and pair-production effects-are becoming feasible and even routine. these studies, motivated by our desire to underst... | radiative relativistic collisionless plasma turbulence as a frontier of extreme plasma astrophysics |
reaction network calculations predict that the crust of an accreting neutron star should host urca reactions: e--capture/β--decay cycles that cool the crust through neutrino emission. neutron star transients offer an opportunity to test this prediction. during accretion outbursts, the crust of a neutron star transient ... | resolving urca cooling reaction layers in neutron stars |
binary neutron star mergers will be important sources of gravitational radiation for advanced ligo. understanding how different physical processes-such as magnetic and microphysical effects due to equations of state or neutrino cooling-are imprinted on the radiation is important for learning more about these systems. w... | gravitational radiation from binary neutron star mergers: magnetic and microphysical effects |
the goal of this work is to investigate the effects of chemical composition of heat blanketing envelopes of neutron stars on their thermal states and thermal evolution. to this purpose, we employ newly constructed models of the envelopes composed of binary ion mixtures (h-he, he-c, c-fe) varying the mass of lighter ion... | the impact of heat blanketing envelopes on neutron stars cooling |
the assembly sequence of our galactic halo is encoded in spectra of its surviving low-metallicity turnoff stars. while the investigation of the heaviest elements (z > 55) reveals they were produced in two independent time scales by rapid- and slow neutron capture (r- and s-process), the light trans-ironic elements w... | tracing the earliest nucleosynthesis from elements just past the iron peak in extremely metal-poor dwarfs |
at a projected separation of 0.1 pc from the supermassive black hole at the center of the milky way, sgr a*, the transient magnetar sgr j1745-2900 holds the record as the closest neutron star to a black hole ever observed. sgr j1745-2900 has been the object of an intensive monitoring campaign in the x-rays for about 1.... | the x-ray outburst of the galactic centre magnetar sgr 1745-2900 during the first 1.5 year |
in light of recent discoveries of pulsating ulxs and recently introduced models placing neutron stars as the central engines of ulxs, we revisit the spectra of seventeen ulxs, in search of indications that favor this hypothesis. to this end we examined the spectra from xmm-newton observations of all seventeen sources i... | ulx spectra revisited: are accreting, highly magnetized neutron stars the engines of ultraluminous x-ray sources? |
to address open questions in neutron star phenomenology, pairing gaps of 1s0 and 3p2 -3f2 channels in a wide range of densities has been calculated using three different interactions (av18 cdbonn n3lo). traditionally, the bardeen-cooper-schrieffer(bcs) approach has been used to compute gaps from bare nucleon-nucleon in... | pairing in high-density neutron matter including short- and long-range correlations |
neutron star is a stellar object that can provide us information on the extreme dense matter. at the central part of neutron stars, the exotic states of matter with strangeness are expected to exist due to the fermionic nature of protons and neutrons that are mainly composed of up and down quarks. strangeness, if exist... | strangeness in neutron star cooling |
type i x-ray bursts are thermonuclear flashes observed from the surfaces of accreting neutron stars (nss) in low mass x-ray binaries. oscillations have been observed during the rise and/or decay of some of these x-ray bursts. those seen during the rise can be well explained by a spreading hot spot model, but large ampl... | x-ray burst oscillations: from flame spreading to the cooling wake |
the gravitational-wave signal of the binary neutron star merger gw170817 was followed by a firework of electromagnetic transients across the entire electromagnetic spectrum. the gamma-ray emission has provided strong evidence for the association of short gamma-ray bursts (sgrbs) with binary neutron star mergers and the... | the firework of electromagnetic counterparts from gw170817 |
recent observational data on transiently-accreting neutron stars has unequivocally shown fast-cooling sources, such as in the case of neutron star mxb 1659-29. previous calculations have estimated its total neutrino luminosity and heat capacity, as well as suggested that direct urca reactions take place in 1% of the vo... | probing dense matter physics with transiently-accreting neutron stars: the case of source mxb 1659-29 |
4u 2129+47 is a quiescent, eclipsing neutron star that 35 years ago showed typical "accretion disk corona" (adc) behavior akin to the prototype of the class, x1822-371. now faded, 4u 2129+47 provides tests of neutron star quiescent emission. it has shown low temperature thermal emission (the neutron star surface), a po... | the quiescent neutron star and hierarchical triple, 4u2129+47 |
the coming decades are set to provide a much deeper understanding of nuclei and neutron stars. the recent observation of neutron star mergers with gravitational and electromagnetic messengers opens a new window to investigate hadronic matter at high densities. the atomic nucleus provides a mini laboratory to extract ph... | illuminating nuclei for neutron stars |
we propose to continue our program to use the crust cooling behaviorin transiently accreting neutron stars. those crusts are heated dueto the matter accretion onto the neutron stars during outbursts. afterthe outbursts the crusts cool down until they are in equilibrium withthe cores again. following this cooling proces... | crust cooling of accretion-heated neutron stars |
we present a new formulation to construct numerically equilibrium configurations of rotating stars in general relativity. having in mind the application to their quasi-static evolutions on a secular time-scale, we adopt a lagrangian formulation of our own devising, in which we solve force-balance equations to seek for ... | a novel lagrangian formulation to construct relativistic rotating stars: towards its application to their evolution calculations |
we request a 60 ks observation of the crust cooling source mxb 1659-29. transient low-mass x-ray binaries exhibit outbursts that result in accretion onto the neutron star and thereby heat up the crust. once the outburst ceases the crust cools to reinstate thermal equilibrium with core. tracking this cooling evolution p... | probing the inner neutron-star crust in the lmxb mxb 1659-29 |
the discovery of 2 solar mass neutron stars, detection of gravitational waves with the concomitant detection of electromagnetic radiation from the binary neutron star merger gw170787, recent reports of additional mergers involving neutron stars, and accumulating data on the cooling of neutron star crusts have all given... | the significance of a neutron star's interior composition |
the dissertation focuses on the study of rotation-powered pulsars, the primary observational manifestation of neutron stars. these objects are powerful sources of electromagnetic radiation and relativistic particles whose emission is provided by the loss of pulsar rotational energy. understanding the evolution of pulsa... | rotation powered pulsars in the x-rays |
neutrino radiation transport plays an important role in the simulation of compact binary mergers involving neutron stars. neutrinos are the main source of cooling of the post-merger remnant. additionally, neutrino-matter interactions in the matter ejected during and after merger are crucial in determining the propertie... | implementation of monte-carlo radiation transport for the treatment of neutrinos in the spec merger code |
transient low mass x-ray binaries (lmxbs) in their quiescent phase are observed to be cooling over timescales of decades. studying this cooling behavior reveals a great deal of information about the properties of neutron stars. the β-decay/e- capture cycles lead to an appreciable cooling of the crust but the strength o... | the role of a=33 mass chain in urca cooling of accreting neutron star crusts |
the crust of a neutron star is an exotic condensed matter system, rich in physics and accessible through a host of astrophysical observables. measurements of individual neutron star cooling and pulsar glitches, of long timescale temperature, magnetic field and rotational evolution evolution by analysis of neutron star ... | nuclear pasta and the deep inner crust |
from flow without dissipation of energy to the formation of vortices when placed within a rotating container, the superfluid state of matter has proven to be a very interesting physical phenomenon. here we present the key mechanisms behind superfluidity in fermionic systems and apply our understanding to an exotic syst... | fermionic superfluidity: from cold atoms to neutron stars |
due the large neutron excess of ne, this isotope rapidly sediments in the interior of the white dwarfs. this process releases an extra amount of energy, thus delaying the cooling times of the white dwarf. furthermore, the overabundance of ne in the inner regions of the star, modifies the brunt-vaisala frequency, thus, ... | el efecto de la difusión del ne en las propiedades evolutivas y pulsacionales de las enanas blancas |
in this work, we present a calculation of the non-fermi liquid correction to the specific heat of magnetized degenerate quark matter present at the core of the neutron star. the role of non-fermi liquid corrections to the neutrino emissivity has been calculated beyond leading order. we extend our result to the evaluati... | role of magnetic interactions in neutron stars |
the composition and structure of the ~1 km thick, solid crust of neutron stars is responsible for many of their observable properties, and plays a fundamental role in the emission of gravitational waves and the evolution of their magnetic field. when residing in an x-ray binary, a neutron star accretes gas from a compa... | observational results from cooling neutron stars in x-ray binaries |
we propose to continue our successful program to use the observed cooling of the crusts in accreting neutron star x-ray systems to probe the properties of ultra-dense matter. those crusts are heated due to matter accretion onto the neutron stars during outburst. after the outbursts are over the crusts should cool down ... | crust cooling of accretion-heated neutron stars |
the equation of state (eos) for dense, beta-equilibrated nuclear matter is a fundamental ingredient for simulations of binary neutron star mergers, calculation of cooling curves, and other transport properties. we construct a new eos using a relativistic-mean-field theory (rmf). typically, the couplings in an rmf are f... | constructing an equation of state from pure neutron matter calculations |
we aim to study the cooling emission of highly magnetized neutron starsin be/x- ray binaries. for this, we need to increase our sample withhigh-quality post-outburst spectra. we require the flexibility of swiftto monitor the behavior of the next potential target, and the exceptionalsensitivity and large effective area ... | on the quest of bex-ray transients: how do highly magnetized neutron stars |
most neutron stars cool predominately via the modified urca process, in which emitted neutrinos carry away energy. the traditional treatment for the in-medium nucleon propagator in the modified urca process uses crude approximations. we reformulate the propagator by including the nucleon self-energy and examine the eff... | improved treatment of neutron star cooling via modified urca process |
we propose xmm-newton observations of two middle-aged radio-quietfermi pulsars j0554+3107 and j0622+3749. the former is associated withthe supernova remnant g179.0+2.6 which provides a great advantagefor confident constraining its distance and evolution stage. usingchandra, erosita and swift shallow exposures we have f... | thermal emission from two middle-aged fermi pulsars j0554+3107 and j0622+3749 |
weve searched for decades for concrete evidence of intermediate-mass black holes, black holes with masses between 100 and 100,000 times that of the sun. in spite of our best efforts, these monsters have remained elusive but a new study provides some hope.searching for the middle siblingillustrations of two types of acc... | new evidence for a middleweight black hole |
generalised polynomial chaos (gpc) in conjunction with sparse grid stochastic collocation and high dimensional model representation (hdmr) is used to perform uncertainty and global sensitivity analysis for the neutron chain survival and extinction probabilities, with and without an intrinsic random source. starting wit... | uncertainty and global sensitivity analysis of neutron survival and extinction probabilities using polynomial chaos |
a superconductor of paired protons is thought to form in the core of neutron stars soon after their birth. minimum energy conditions suggest that magnetic flux is expelled from the superconducting region due to the meissner effect, such that the neutron star core retains or is largely devoid of magnetic fields for some... | onset of superconductivity and retention of magnetic fields in cooling neutron stars |
core collapse in stars at the lower range of massive stars (8-10 m⊙) have different behaviors relative to more massive counterparts where relatively lengthy neutrino driven convection is required to relaunch the stalled bounce shock. we compute the collapse, bounce, and explosive revival of the supernova shock in a zer... | supernovae in the borderlands: simulating the explosion of a low-mass supernova progenitor |
we report on the effects of strong magnetic fields on neutrino emission in the modified urca process. we show that the effect of landau levels on the various urca pairs affects the neutrino emission spectrum and leads to an angular asymmetry in the neutrino emission. for low magnetic fields, the landau levels have almo... | evolution of urca pairs in the crusts of highly magnetized neutron stars |
pulsars are rapidly rotating neutron stars with plasma-filled magnetospheres that radiate their rotational energy in the form of poynting flux, also referred to as the spin-down power. some of the young pulsars exhibit rotation-modulated gamma-ray emission, captured by the fermi observatory. the luminosity of this emis... | energy dissipation and gamma-ray emission in young pulsars |
we describe the results of an ongoing survey of x-ray selected symbiotics in the galactic bulge, begun with the galactic bulge survey and now extended to the wider bulge using the chandra source catalog. chandra's sensitivity and source localization are well suited to finding symbiotic x-ray binaries (syxbs) containing... | multiwavelength follow-up of x-ray selected symbiotic candidates in the galactic bulge |
gamma ray heating rates are thought to play a crucial role during the pre-supernova stage of high mass stars. gamma ray heating rates, due to β±-decay and electron (positron) capture on chromium isotopes, are calculated using proton-neutron quasiparticle random phase approximation theory. the electron capture significa... | gamma ray heating rates due to chromium isotopes in stellar core during late stages of high mass stars (>10m⊙) |
this paper provides an overview of the capabilities of a new toolset that is being developed at canadian nuclear laboratories for modelling advanced non-water cooled small modular reactor concepts. throughout the study, a technology agnostic approach was adopted. the integrated toolset includes computational fluid dyna... | demonstration of a coupled computational fluid dynamics approach for modelling non-water cooled small modular reactors |
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