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transient low-mass x-ray binaries (lmxbs) that host neutron stars (nss) provide excellent laboratories for probing the dense matter physics present in ns crusts. during accretion outbursts in lmxbs, exothermic reactions may heat the ns crust, disrupting the crust-core equilibrium. when the outburst ceases, the crust co... | unexpected late-time temperature increase observed in the two neutron star crust-cooling sources xte j1701-462 and exo 0748-676 |
the existence of ev-mass sterile neutrinos is not ruled out because of persistent experimental anomalies. upcoming multimessenger detections of neutron-star merger remnants could provide indirect constraints on the existence of these particles. we explore the active-sterile flavor conversion phenomenology in a two-flav... | resonant production of light sterile neutrinos in compact binary merger remnants |
the evolution of magnetic field in isolated neutron stars is one of the most important ingredients in the attempt to build a unified description of these objects. a prediction of field evolution models is the existence of an equilibrium configuration, in which the hall cascade vanishes. recent calculations have explore... | probing the surface magnetic field structure in rx j1856.5-3754 |
background: low-lying collective excitations of the inner crust matter in neutron stars are expected to affect observables such as the quasiperiodic oscillation in giant flares or cooling of the inner crust in transient phenomena. the coupling between the anderson-bogoliubov (ab) superfluid phonon in superfluid neutron... | coexistence of anderson-bogoliubov phonon and quadrupole cluster vibration in the inner crust of neutron stars |
in the present work we used five different versions of the quark-meson coupling (qmc) model to compute astrophysical quantities related to the gw170817 event and to neutron star cooling process. two of the models are based on the original bag potential structure and three versions consider a harmonic oscillator potenti... | neutron star cooling and gw170817 constraint within quark-meson coupling models |
our bimetric spacetime model of glitching pulsars is applied to the remnant of gw170817. accordingly, pulsars are born with embryonic incompressible superconducting gluon-quark superfluid cores (susu-matter) that are embedded in minkowski spacetime, whereas the ambient compressible and dissipative media (cdm) are imbed... | the remnant of gw170817: a trapped neutron star with a massive incompressible superfluid core |
we study the ν ν bar -pair synchrotron emission from electrons and protons in a relativistic quantum approach. this process occurs only in the presence of 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 ν ν bar -pai... | ν ν bar -pair synchrotron emission in neutron-star matter based on a relativistic quantum approach |
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 |
crust cooling of soft x-ray transients has been observed after outbursts, but an additional shallow heating during accretion in outburst is needed to explain the quiescent light curve. however, shallow heating is significantly different between sources and even within one source between different outbursts, and the sou... | crust cooling of soft x-ray transients-the uncertainties of shallow heating |
the influence of short-range correlations (src) on the spectral distribution of neutrons is incorporated in the solution of the gap equation for the ${}^3p_2-{}^3f_2$ coupled channel in pure neutron matter at high density. this effect is studied for three different realistic interactions. the gap in this channel is str... | pairing in high-density neutron matter including short- and long-range correlations |
psr j1119-6127 is a radio pulsar that behaved with magnetar-like bursts, and we performed a comprehensive investigation of this pulsar using the archival high-energy observations obtained after its outburst in 2016 july. after the 2016 outburst, specific regions on the neutron star (ns) surface were heated up to >0.... | investigation of the high-energy emission from the magnetar-like pulsar psr j1119-6127 after the 2016 outburst |
we present the results of a 30 ks xmm-newton observation of the supergiant fast x-ray transient (sfxt) sax j1818.6-1703 - the first in-depth soft x-ray study of this source around periastron. integral observations shortly before and after the xmm-newton observation show the source to be in an atypically active state. o... | spectral variation in the supergiant fast x-ray transient sax j1818.6-1703 observed by xmm-newton and integral |
we explore spectral properties of a two-component advective flow around a neutron star. we compute the effects of thermal comptonization of soft photons emitted from a keplerian disc and the boundary layer of the neutron star by the post-shock region of a sub-keplerian flow, formed due to the centrifugal barrier. the s... | monte carlo simulations of thermal comptonization process in a two-component advective flow around a neutron star |
thermal evolution of neutron stars is studied in the f (r )=r +α r2 theory of gravity. we first review the equations of stellar structure and evolution for a spherically symmetric spacetime plus a perfect fluid at rest. we then present numerical results for the structure of neutron stars using four nucleonic dense matt... | probing strong field f (r ) gravity and ultradense matter with the structure and thermal evolution of neutron stars |
cowan et al. review how roughly half the elements heavier than iron found in the sun are produced by rapid neutron capture and half by slow neutron capture, the r- and s-processes. in the sun, their relative contribution to individual elemental abundances is well understood, except for the lightest and heaviest element... | the abundance of lead in four metal-poor stars |
we study the long-term thermal evolution of axisymmetric rotating neutron stars in full general relativity. to this aim, we develop nscool 2d rot, a major upgrade to the 1d neutron stars thermal evolution code nscool by page. as a first application of our new code, we address the standard cooling of isolated neutron st... | standard cooling of rapidly rotating isolated neutron stars in 2d |
we apply the model of subsonic settling accretion on to isolated neutron stars accreting from the interstellar medium (ains). we show that in this regime the expected mean x-ray luminosity from ains turns out to be two to three orders of magnitude as small as the maximum possible bondi value, i.e. 1027-1028 erg s-1. th... | settling accretion on to isolated neutron stars from interstellar medium |
the macroscopic magnetic properties and microscopic magnetic structure of rb2mn3(moo4)3(oh) 2 (space group p n m a ) are investigated by magnetization, heat capacity, and single-crystal neutron diffraction measurements. the compound's crystal structure contains bond-alternating [mn3o11] ∞ chains along the b axis, forme... | complex magnetic order in the decorated spin-chain system rb2mn3(moo4)3(oh) 2 |
aquatic habitats are severely threatened by human activities. for anadromous species, managing freshwater habitats to maximize production of more, larger juveniles could improve resilience to threats in marine habitats and enhance population viability. in some juvenile salmonid habitats, complexity created by large sub... | high summer macrophyte cover increases abundance, growth, and feeding of juvenile atlantic salmon |
we study the diversities in the properties of the neutron stars arising due to the different choices for the cross coupling between various mesons, which governs the density dependence of the nuclear symmetry energy in the extended relativistic mean-field (rmf) model. for this purpose, we obtain two different families ... | diversity of neutron star properties at the fixed neutron-skin thickness of 208pb |
the heat capacity of neutron matter is studied over the range of densities and temperatures prevailing in neutron-star crusts, allowing for the transition to a superfluid phase at temperatures below some critical temperature tsf and including the transition to the classical limit. finite-temperature hartree-fock-bogoli... | heat capacity of low-density neutron matter: from quantum to classical regimes |
we analyzed the influence of the density profile on neutron star cooling by neutrino emission, considering four different equations of state. after interpolated density profiles are obtained from discrete data, we calculate numerically, as a function of the radial distance to the center of the star, the following quant... | about the influence of the density profile on neutron star cooling by neutrino emission |
fast radio bursts (frbs) at cosmological distances still hold concealed physical origins. previously liu (2018) proposes a scenario that the collision between a neutron star (ns) and a white dwarf (wd) can be one of the progenitors of non-repeating frbs and notices that the repeating frbs can also be explained if a mag... | the remnant of neutron star-white dwarf merger and the repeating fast radio bursts |
the process of a non-equilibrium chemical composition formation during cooling due to neutrino energy loss in the shells of hot, formed neutron stars is considered. a model constructed is to explain the presence of a large quantity of nuclear energy accumulated, which can maintain the x-ray luminosity of such compact o... | dynamic model of a non-equilibrium chemical composition formation in the shell of single neutron stars |
a detailed description of the baryon direct urca processes a: n\to p+e+{\bar{ν }}e, b: λ \to p+e+{\bar{ν }}e and c: {\xi }-\to λ +e+{\bar{ν }}e related to the neutron star cooling is given in the relativistic mean field approximation. the contributions of the reactions b and c on the neutrino luminosity are calculated ... | direct urca processes involving proton 1 s 0 superfluidity in neutron star cooling |
the radiative-condensation instability (rci) in self-gravitating strongly coupled dusty plasma (scdp) is investigated considering the effects of dust thermal velocity and polarization force on the massive dust particulates. in particular, the outer core of the dense neutron star which is supposed to be strongly coupled... | radiative-condensation instability in gravitating strongly coupled dusty plasma with polarization force |
gw170817 was the first detection of a binary neutron star merger via gravitational waves. the event was observed over a wide range of the electromagnetic spectrum, revealing a thermal kilonova dominating the optical signal during the first ∼15 days, and a non-thermal synchrotron emission that has continued to rise ∼200... | cooling off with a kilonova - lower limit on the expansion velocity of gw170817 |
we report the results of a long-term spectral and timing study of the first transient magnetar, xte j1810-197 which was discovered in 2003, when its x-ray luminosity increased ≈ 100 fold. we fit x-ray spectra of all archival x-ray observations using a two-component blackbody model, where the cool component is most like... | variable absorption line in xte j1810-197 |
polish doughnuts (pds) are geometrically thick disks that rotate with super-keplerian velocities in their innermost parts, and whose long and narrow funnels along rotation axes collimate the emerging radiation into beams. in this paper we construct an extremal family of pds that maximize both geometrical thickness and ... | limits on thickness and efficiency of polish doughnuts in application to the ulx sources |
thermal emission of neutron stars in soft x-ray transients (sxts) in a quiescent state is believed to be powered by the heat deposited in the stellar crust due to nuclear reactions during accretion (deep crustal heating paradigm). confronting observations of sxts with simulations helps to verify theoretical models of t... | thermal evolution of neutron stars in soft x-ray transients with thermodynamically consistent models of the accreted crust |
young isolated neutron stars (inss) most commonly manifest themselves as rotationally powered pulsars that involve conventional radio pulsars as well as gamma-ray pulsars and rotating radio transients. some other young ins families manifest themselves as anomalous x-ray pulsars and soft gamma-ray repeaters that are com... | classification of pulsars with dirichlet process gaussian mixture model |
type-ia supernovas are powerful stellar explosions that provide important distance indicators in cosmology. recently, we proposed a new type-ia supernova mechanism that involves a nuclear fission chain-reaction in an isolated white dwarf [phys. rev. lett. 126, 131101 (2021), 10.1103/physrevlett.126.131101]. here we per... | nuclear fission reaction simulations in compact stars |
we performed penning trap mass measurements for 61zn at the national superconducting cyclotron laboratory and nushellx calculations of the 61zn and 62ga structure using the gxpf1a hamiltonian to obtain improved estimates of the 61zn(p ,γ )62ga and 60cu(p ,γ )61zn reaction rates. surveying astrophysical conditions for t... | improved nuclear physics near a =61 refines urca neutrino luminosities in accreted neutron star crusts |
a novel mathematical and computational model for the formation and evolution of radiolytic gas in aqueous fissile solutions is presented. the model predicts the rate at which bubbles are formed and/or removed from the system using semi-empirical correlations calibrated by means of numerical simulation. the model is abl... | a semi-empirical model of radiolytic gas bubble formation and evolution during criticality excursions in uranyl nitrate solutions for nuclear criticality safety assessment |
we report detection of the binary companion to the millisecond pulsar j2302+4442 based on the deep observations performed with the gran telescopio canarias. the observations revealed an optical source with r' = 23.33 ± 0.02 and i' = 23.08 ± 0.02, whose position coincides with the pulsar radio position. by comparing the... | optical identification of the binary companion to the millisecond psr j2302+4442 with the gran telescopio canarias |
accreting neutron stars (ns) can exhibit high frequency modulations in their light curves during thermonuclear x-ray bursts, known as burst oscillations. the frequencies can be offset from the spin frequency of the ns by several hz, and can drift by 1-3 hz. one possible explanation is a mode in the bursting ocean, the ... | superburst oscillations: ocean and crustal modes excited by carbon-triggered type i x-ray bursts |
we investigate the cooling of neutron stars with relativistic and non-relativistic models of dense nuclear matter. we focus on the effects of uncertainties originated from the nuclear models, the composition of elements in the envelope region, and the formation of superfluidity in the core and the crust of neutron star... | nuclear equation of state and neutron star cooling |
investigation of the long-term evolution of rotating radio transients (rrats) is important to understand the evolutionary connections between the isolated neutron star populations in a single picture. the x-ray luminosities of rrats (except one source) are not known. in the fallback disc model, we have developed a meth... | on the long-term evolution of rotating radio transients |
in this paper, we studied thermal evolution of isolated neutron stars (nss) including the pion condensation core, with an emphasis on the stiffness of equation of state (eos). many temperature observations can be explained by the minimal cooling scenario which excludes the fast neutrino cooling process. however, severa... | cooling of isolated neutron stars with pion condensation: possible fast cooling in a low-symmetry energy model |
superfluid neutron matter is a key ingredient in the composition of neutron stars. the physics of the inner crust are largely dependent on those of its s-wave neutron superfluid, which has made its presence known through pulsar glitches and modifications in neutron star cooling. moreover, with recent gravitational-wave... | superfluid neutron matter with a twist |
evolution of a large part of low-mass x-ray binaries (lmxbs) leads to the formation of rapidly rotating pulsars with a helium white dwarf (he wd) companion. observations indicate that some he wds in binary pulsar systems are ultracool (with the effective temperatures teff ≲ 4000 k). it is hard to cool down a he wd to s... | on the effect of pulsar evaporation on the cooling of white dwarfs |
this paper concerns numerical comparisons between five mathematical models capable of modelling the stochastic behaviour of neutrons in low extraneous (extrinsic or fixed) neutron source applications. these models include analog monte-carlo (amc), forward probability balance equations (fpb), generating function form of... | numerical comparison of mathematical and computational models for the simulation of stochastic neutron kinetics problems |
the many-body theory of asymmetric nuclear matter is developed beyond the brueckner-hartree-fock approximation to incorporate the medium polarization effects. the extension is performed within the babu-brown induced interaction theory. after deriving the particle-hole interaction in the form of landau-migdal parameters... | medium polarization and pairing in asymmetric nuclear matter |
we have observed the neutron star low-mass x-ray binary sax j1810.8-2609 in quiescence with xmm-newton. sax j1810.8-2609 is one of the faintest non-pulsing neutron star low-mass x-ray binaries in quiescence and previously only had upper limits on its quiescent thermal emission. we found sax j1810.8-2609 at the same 0.5... | thermal emission in the quiescent neutron star sax j1810.8-2609 |
based on new chandra x-ray telescope data, we present empirical evidence of plasma compton cooling during a flare in the non-pulsating massive x-ray binary 4u1700-37. this behaviour might be explained by quasi-spherical accretion on to a slowly rotating magnetized neutron star (ns). in quiescence, the ns in 4u1700-37 i... | evidence of compton cooling during an x-ray flare supports a neutron star nature of the compact object in 4u1700-37 |
context. 4u 1538-52, an absorbed high mass x-ray binary with an orbital period of ~3.73 days, shows moderate orbital intensity modulations with a low level of counts during the eclipse. several models have been proposed to explain the accretion at different orbital phases by a spherically symmetric stellar wind from th... | orbital phase-resolved spectroscopy of 4u 1538-52 with maxi |
we present here the solutions of magnetized accretion flow on to a compact object with hard surface such as neutron stars. the magnetic field of the central star is assumed dipolar and the magnetic axis is assumed to be aligned with the rotation axis of the star. we have used an equation of state for the accreting flui... | study of magnetized accretion flow with variable γ equation of state |
the cooling of type-i x-ray bursts can be used to probe the nuclear burning conditions in neutron star envelopes. the flux decay of the bursts has been traditionally modelled with an exponential, even if theoretical considerations predict power-law-like decays. we have analysed a total of 540 type-i x-ray bursts from f... | flux decay during thermonuclear x-ray bursts analysed with the dynamic power-law index method |
exploiting a stiff equation of state of the relativistic mean-field model mkvorh ϕ with σ -scaled hadron effective masses and couplings, including hyperons, we demonstrate that the existing neutron-star cooling data can be appropriately described within "the nuclear medium cooling scenario" under the assumption that di... | on cooling of neutron stars with a stiff equation of state including hyperons |
we investigate the thermal stability of optically thin, two-temperature, radiative cooling-dominated accretion disks. our linear analysis shows that the disk is thermally unstable without magnetic fields, which agrees with previous stability analysis on the shapiro-lightman-eardley disk. by taking into account the effe... | thermal stability of magnetized, optically thin, radiative cooling-dominated accretion disks |
context. during the third all-sky survey (erass3), erosita, the soft x-ray instrument aboard spectrum-roentgen-gamma, detected a new hard x-ray transient, erasst j040515.6 − 745202, in the direction of the magellanic bridge.aims: we arranged follow-up observations and searched for archival data to reveal the nature of ... | erasst j040515.6 − 745202, an x-ray burster in the magellanic bridge |
we study the thermal evolution of neutron stars in the presence of hyperons or kaons in the core. our results indicate that the nucleon and hyperon direct urca processes play crucial roles for the cooling of neutron stars. the presence of hyperons drives fast cooling mechanisms in two ways: 1) it allows the hyperon dir... | strangeness in neutron star cooling |
in 2017, the be/x-ray transient 4u 0115+63 exhibited a new type ii outburst that was two times fainter than its 2015 giant outburst (in the swift/bat count rates). despite this difference between the two bright events, the source displayed similar x-ray behaviour after these periods. once the outbursts ceased, the sour... | recurrent low-level luminosity behaviour after a giant outburst in the be/x-ray transient 4u 0115+63 |
we suggest the generalization of the anomalous magneto-hydro-dynamics (amhd) in the chiral plasma of a neutron star (ns) accounting for the mean spin in the ultrarelativistic degenerate electron gas within the magnetized ns core as a continuing source of the chiral magnetic effect. using the mean field dynamo model gen... | permanent mean spin source of the chiral magnetic effect in neutron stars |
we model a gyroscope that exploits quantum effects in an atomic bose-einstein condensate to gain a tunable enhancement in precision. current inertial navigation systems rely on the sagnac effect using unentangled photons in fibre-optic systems and there are proposals for improving how the precision scales with the numb... | quantum-enhanced atomic gyroscope with tunable precision |
the outpouring of radiation during an x-ray burst can affect the properties of accretion discs around neutron stars: the corona can cool and collapse, the inner regions can be bled away due to enhanced accretion, and the additional heating will lead to changes in the disc height. in this paper, we investigate whether r... | radiation-driven warping of accretion discs due to x-ray bursts |
detection of delayed sub-tev photons from gamma-ray bursts (grbs) by magic and hess has proven the promising future of grb afterglow studies with the cherenkov telescope array (cta), the next-generation gamma-ray observatory. with the unprecedented sensitivity of cta, afterglow detection rates are expected to increase ... | probing gamma-ray burst afterglows with the cherenkov telescope array |
a recent study of a small sample of x-ray binaries (xrbs) suggests a significant softening of spectra of neutron star (ns) binaries as compared to black hole (bh) binaries in the luminosity range 1034-1037 erg s-1. this softening is quantified as an anticorrelation between the spectral index and the 0.5-10 kev x-ray lu... | a study of low-mass x-ray binaries in the low-luminosity regime |
the neutrino cooling and gamma heating rates are considered as an important input needed to study the final phases of the evolution of high-mass stars. the weak-interaction mediated processes, namely the β -decay and electron capture, significantly change the lepton to baryon ratio and accelerate the contraction of the... | energy rates due to weak decay rates of vanadium isotopes in stellar environment |
nanostructured tas2 with different concentrations of intercalated mn ions has been investigated using ac and dc magnetization measurements. the nanostructures are composed of tapes that are less than a micron wide, which themselves are comprised of tubular structures with an average diameter of about 100 nm. the sample... | magnetic states in nanostructured manganese-intercalated tas2 |
this study investigates the relativistic neutrino emissivity of the nucleonic and hyperonic direct urca processes in the degenerate baryon matter of neutron stars, within the framework of relativistic mean field theory. in particular, we study the influence of the isovector scalar interaction on the nucleonic and hyper... | effects of δ mesons on baryonic direct urca processes in neutron star matter |
the observations combined with theory of neutron star (ns) cooling play a crucial role in achieving the intriguing information of the stellar interior, such as the equation of state, composition, and superfluidity of dense matter. the traditional ns cooling theory is based on the assumption that the stellar structure d... | neutron star cooling with a dynamic stellar structure |
an extension of the standard model (sm) is studied, in which two new vector bosons are introduced, a first boson z' coupled to the sm by the usual minimal coupling, producing an enlarged gauge sector in the sm. the second boson a' field, in the dark sector of the model, remains massless and originates a dark photon γ'.... | astrophysical aspects of milli-charged dark matter in a higgs-stueckelberg model |
the be x-ray pulsar (bexrp) sxp 59 underwent a giant outburst in 2017 with a peak x-ray luminosity of 1.1 × 1038 erg s-1. we report on the x-ray behaviour of sxp 59 with the xmm-newton and nustar observations collected at the outburst peak, decay, and the low luminosity states. the pulse profiles are energy dependent, ... | nustar and xmm-newton observations of sxp 59 during its 2017 giant outburst |
the 1s0 nucleonic superfluids are investigated within the relativistic mean-field model and bardeen-cooper-schrieffer theory in hyperonic neutron stars. the 1s0 pairing gaps of neutrons and protons are calculated based on the reid soft-core interaction as the nucleon-nucleon interaction. in particular, we have studied ... | singlet pairing gaps of neutrons and protons in hyperonic neutron stars |
the loss of magnetic pressure accompanying the decay of the magnetic field in a magnetar may trigger exothermic electron captures by nuclei in the shallow layers of the stellar crust. very accurate analytical formulas are obtained for the threshold density and pressure, as well as for the maximum amount of heat that ca... | onset of electron captures and shallow heating in magnetars |
the mutual correlation between the nuclear equation of state (eos) and the bulk properties of neutron stars (ns) is crucial in probing both of them. here, we use eoss of hot n p e (n p e μ ) nuclear matter, based on the density-dependent cdm3y-paris nucleon-nucleon interaction in the nonrelativistic hartree-fock scheme... | investigation of the inner edge of neutron star crusts: temperature dependence and related effects |
neutron stars offer the opportunity to study the behaviour of matter at densities and temperatures inaccessible to terrestrial experiments. gravitational-wave observations of binary neutron star coalescences can constrain the neutron-star equation of state before and after merger. after the neutron star binary merges, ... | temperature dependent appearance of exotic matter makes nascent neutron stars spin faster |
recent advances in the field of ultracold quantum gases have played an important role in expanding our understanding of strongly correlated quantum matter. these gases are isolated, clean and fully controllable systems, allowing bottom-up engineering of idealized condensed matter models. interacting fermi gases are par... | exploring attractively interacting fermions in 2d using a quantum gas microscope |
glitches, sudden spin-up of pulsars with subsequent recovery, provide us with a unique opportunity to investigate various physical processes, including the crust-core coupling, distribution of reservoir angular momentum within different internal layers, spin-up in neutral and charged superfluids and constraining the eq... | glitches as probes of neutron star internal structure and dynamics: effects of the superfluid-superconducting core |
for the first time, we present a bayesian time-resolved spectral study of the x-ray afterglow datasets of gw170817/grb17017a observed by the chandra x-ray observatory. these include all 12 public datasets, from the earliest observation taken at t ∼ 9 d to the newest observation at ∼359 d post-merger. while our results ... | bayesian analysis on the x-ray spectra of the binary neutron star merger gw170817 |
we discuss the effect of compression on urca shells in the ocean and crust of accreting neutron stars, especially in superbursting sources. we find that urca shells may be deviated from chemical equilibrium in neutron stars which accrete at several tenths of the local eddington accretion rate. the deviation depends on ... | net reaction rate and neutrino emissivity for the urca process in departure from chemical equilibrium |
strongly magnetized isolated neutron stars (nss) are categorized into two families according, mainly, to their magnetic field strength. the one with a higher magnetic field of 1014–1015 gauss is called "magnetar," and the other is the x‑ray isolated neutron star (xins) with 1013 gauss. both magnetars and xinss show the... | unification of strongly magnetized neutron stars with regard to x‑ray emission from hot spots |
we present the results of our extensive search using the bayesian block method for long tails following short bursts from a magnetar, sgr j1550-5418, over all rxte observations of the source. we identified four bursts with extended tails, most of which occurred during its 2009 burst active episode. the durations of tai... | burst tails from sgr j1550-5418 observed with the rossi x-ray timing explorer |
the defining trait of magnetars, the most strongly magnetized neutron stars (nss), is their transient activity in the x/γ-bands. in particular, many of them undergo phases of enhanced emission, the so-called outbursts, during which the luminosity rises by a factor ~10-1000 in a few hours to then decay over months/years... | three-dimensional magnetothermal simulations of magnetar outbursts |
background: neutrino-pair bremsstrahlung processes from nucleon-nucleon scattering n n ν ν ¯ (n n ν ν ¯ ,p p ν ν ¯ , and n p ν ν ¯ ) have recently attracted attention in studies of neutrino emission in neutron stars, because of the implications for the neutron star cooling. the calculated n n ν ν ¯ emissivities within ... | neutrino-pair bremsstrahlung from nucleon-nucleon scattering |
this paper reviews the properties of neutron stars based on the recent multi-messenger observations including electromagnetic waves from the low-mass x-ray binaries and gravitational waves from the merger of neutron star binaries. based on these observations, we investigate theoretical models for dense nuclear matter a... | neutron star equations of state and their applications |
in the relativistic mean field theory and cooling theories, relativistic correction on neutrino emission from neutron stars in four typical nuclear parameter sets, gm1, gl85, gps250 and gps300 is studied. results show that relativistic effect makes the neutrino emissivity, neutrino luminosity and cooling rate lower, co... | relativistic correction on neutrino emission from neutron stars in various parameter sets |
numerical simulations of radiative two-temperature hot accretion flows (hafs) around neutron stars (nss) are performed. we assume that all of the energy carried by the haf around a ns will be thermalized and radiated out at the surface of the ns. the thermal photons will propagate outwards radially and cool the haf via... | two-temperature radiative hot accretion flow around neutron stars |
we present our broadband (2-250 kev) time-averaged spectral analysis of 388 bursts from sgr j1550-5418, sgr 1900+14, and sgr 1806-20 detected with the rossi x-ray timing explorer (rxte) here and as a database in a companion web-catalog. we find that two blackbody functions (bb+bb), the sum of two modified blackbody fun... | broadband spectral investigations of magnetar bursts |
we study the evolution of close binary systems in order to account for the existence of the recently observed binary system containing the most massive millisecond pulsar ever detected, psr j0740+6620, and its ultra-cool helium white dwarf companion. in order to find a progenitor for this object we compute the evolutio... | binary evolution leading to the formation of the very massive neutron star in the j0740+6620 binary system |
we briefly review the role played by hyperons in determining the properties of neutron and proto-neutron stars. in particular, we review the so-called "hyperon puzzle", i.e., the problem of strong softening of the equation of state (eos) of dense matter due to the presence of hyperons which leads to maximum masses of c... | do hyperons exist in the neutron star interior? |
isolated pulsars are ideal sources for polarisation studies since the radiation from pulsars generally covers a wide range of wavelengths from radio to very-high-energy γ-rays and the pulsed emission is closely tied to the local magnetic field direction. although radio polarisation data exist for many pulsars, polarisa... | multi-wavelength polarimetry of isolated pulsars |
analytical expressions for the specific heat of superfluid fermi liquids (sfls) with anisotropic spin-triplet p-wave pairing of the 3he-a type have been obtained based on a generalised fermi-liquid approach both at the low temperatures of 0 < t ≪tc0 (n) and near the temperature of the phase transition [tc0 (n)] from... | analytical derivation of expressions for the specific heat of superfluid fermi liquids with anisotropic spin-triplet p-wave pairing at finite temperatures |
within the "nuclear medium cooling" scenario of neutron stars all reliably known temperature - age data, including those of the central compact objects in the supernova remnants of cassiopeia a and xmmu-j1732, can be comfortably explained by a set of cooling curves obtained by variation of the star mass within the rang... | cooling of neutron stars and hybrid stars with a stiff hadronic eos |
in accreting neutron star x-ray transients, the neutron star crust can be substantially heated out of thermal equilibrium with the core during an accretion outburst. the observed subsequent cooling in quiescence (when accretion has halted) offers a unique opportunity to study the structure and thermal properties of the... | a window into the neutron star: modelling the cooling of accretion heated neutron star crusts |
we perform for the first time hydrodynamic simulations to study the properties of hot accretion flow (haf) around a neutron star (ns). the energy carried by the haf will eventually be radiated out at the surface of the ns. the emitted photons can propagate inside the haf and cool the haf via comptonization. we find tha... | hot accretion flow around 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 2$m_{\odot}$ neutron stars, and generate neutron star radii below 13 km. maki... | the equation of state and cooling of hyperonic neutron stars |
the large magellanic cloud supernova remnant j0453-6655 in the h ii region n4 has been observed with xmm-newton and with chandra. almost all of the diffuse x-ray emission is from within a 3.‧5 × 2.‧3 region of bright optical filaments, and x-ray results from xmm-newton and chandra are very similar. spectra indicate tha... | j0453-6655, the supernova remnant in n4d |
several phenomena occurring in neutron stars are affected by the elementary excitations that characterize the stellar matter. in particular, low-energy excitations can play a major role in the emission and propagation of neutrinos, neutron star cooling, and transport processes. in this paper, we consider the elementary... | coupling between superfluid neutrons and superfluid protons in the elementary excitations of neutron star matter |
i consider differential rotation, associated with radiation-driven chandrasekhar-friedman-schutz (cfs) instability, and respective observational manifestations. i focus on the evolution of the apparent spin frequency, which is typically associated with the motion of a specific point on the stellar surface (e.g. polar c... | long-term evolution of cfs-unstable neutron stars and the role of differential rotation on short time-scales |
the neutron star ocean is a plasma of ions and electrons that extends from the base of the neutron star’s envelope to a depth where the plasma crystallizes into a solid crust. during an accretion outburst in an x-ray transient, material accumulates in the envelope of the neutron star primary. this accumulation compress... | ocean g-modes on transient neutron stars |
psr b0656+14 is a middle-aged rotation-powered pulsar and a member of the “three musketeers,” which also includes geminga and psr b1055-52. these pulsars show complex, multi-component pulsed x-ray emission best fit with two thermal spectra plus a power law. psr b0656+14 has been extensively observed by nicer since its ... | nicer observations of the thermal emission from psr b0656+14 |
probing quark matter is one of the important tasks in the studies of neutron stars (ns). some works explicitly consider the existence of quark matter in the appearance of hybrid star (hs) or pure quark star (qs). in the present work, we study the roto-chemical heating with accretion in hs and qs, and compare their chem... | roto-chemical heating with fall-back disk accretion in the neutron stars containing quark matter |
in newtonian physics, higher temperature leads to higher thermal pressure, which provides stronger support against the gravitational contraction of stars. however, in the temperature range of tens of mev involved in the evolution of a proto-neutron star or a higher massive neutron star, the effects of temperature are r... | effects of temperature on the structure of neutron stars at high temperature |
we study in this work the evolution of the magnetic field in `redback-black widow' pulsars. evolutionary calculations of these `spider' systems suggest that first the accretion operates in the redback stage, and later the companion star ablates matter due to winds from the recycled pulsar. it is generally believed that... | magnetic field decay in black widow pulsars |
we discuss the structure of neutron stars by modelling the homogeneous nuclear matter of the core by a suitable microscopic equation of state, based on the brueckner-hartree-fock many-body theory, and the crust, including the pasta phase, by the bcpm energy density functional which is based on the same equation of stat... | a unified equation of state on a microscopic basis : implications for neutron stars structure and cooling |
we briefly review a simple method to analyse observations of cooling neutron stars (developed in our previous works) and discuss its applications to xmmu j173203.3-244518, rx j1856.5-3754 and the vela pulsar. | cooling status of three neutron stars |
the 1s 0 nucleon superfluidity in neutron star matter was investigated in the framework of relativistic σ-ω-π-ρ model with the tensor couplings of ω and ρ mesons using the relativistic hartree-fock (rhf) approximation. it was found that the tensor couplings of ω and ρ mesons lead to a clear growth of the 1s 0 neutron p... | effects of tensor couplings of ω and ρ mesons on 1s0 nucleon superfluidity in neutron star matter |
we investigate structure and cooling properties of neutron stars making use of microscopic descriptions of nuclear matter based on realistic nucleon-nucleon interactions. the equation of state is obtained from solutions of the brueckner-hartree-fock equation for interacting nucleons at zero temperature. the structure a... | structure and cooling of neutron stars: nuclear pairing and superfluid effects |
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