scholarly journals The Pulsar Magnetic Window

1981 ◽  
Vol 95 ◽  
pp. 103-105 ◽  
Author(s):  
C. S. Shukre ◽  
V. Radhakrishnan
Keyword(s):  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Gamma Rays ◽  
Narrow Range ◽  
Spark Discharges ◽  
Sutherland Model ◽  
Good Agreement ◽  
Field Strengths

Triggering of the spark discharges in the Ruderman and Sutherland model by background gamma rays is shown to be effective only within a narrow range of neutron star magnetic fields centred on 2.5 × 1012 gauss. This calculated range of field strengths is in good agreement with ‘observed’ values, suggesting that (a) such triggering is operative, and (b) that neutron stars with much stronger fields do not function as pulsars.

scholarly journals Magnetic White Dwarfs with Strong Fields and the Origin of Magnetism in White Dwarfs and Neutron Stars

1979 ◽  
Vol 53 ◽  
pp. 313-316 ◽  
Author(s):  
J. R. P. Angel
Keyword(s):  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
White Dwarf ◽  
White Dwarfs ◽  
Strong Fields ◽  
Work In Progress ◽  
Field Strengths

Work in progress at Steward Observatory covering three aspects of magnetism in degenerate dwarfs is reviewed. First, the identification of the Minkowski bands in Grw + 70° 8247 with Zeeman transitions in hydrogen. Second, a determination of field strengths in the more strongly magnetic white dwarfs. Third, some observations and speculations concerning the origin of white dwarf and neutron star magnetic fields.

scholarly journals Onset of superconductivity and retention of magnetic fields in cooling neutron stars

2017 ◽  
Vol 13 (S337) ◽  
pp. 213-216
Author(s):  
Wynn C. G. Ho ◽  
Nils Andersson ◽  
Vanessa Graber
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Minimum Energy ◽  
Meissner Effect ◽  
Energy Conditions ◽  
Field Diffusion ◽  
Neutron Star Cooling ◽  
Proton Pairing

AbstractA 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 nuclear equation of state and proton pairing models. We show via neutron star cooling simulations that the superconducting region expands faster than flux is expected to be expelled because cooling timescales are much shorter than timescales of magnetic field diffusion. Thus magnetic fields remain in the bulk of the neutron star core for at least 106 − 107yr. We estimate the size of flux free regions at 107yr to be ≲ 100m for a magnetic field of 1011G and possibly smaller for stronger field strengths.

scholarly journals Constraints on Microscopic and Phenomenological Equations of State of Dense Matter from GW170817

Universe ◽  
2019 ◽  
Vol 5 (10) ◽  
pp. 204 ◽  
Author(s):  
Domenico Logoteta ◽  
Ignazio Bombaci
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Equations Of State ◽  
Mean Field ◽  
Dense Matter ◽  
Neutron Star Matter ◽  
Field Approach ◽  
Relativistic Mean Field ◽  
Three Body ◽  
Good Agreement

We discuss the constraints on the equation of state (EOS) of neutron star matter obtained by the data analysis of the neutron star-neutron star merger in the event GW170807. To this scope, we consider two recent microscopic EOS models computed starting from two-body and three-body nuclear interactions derived using chiral perturbation theory. For comparison, we also use three representative phenomenological EOS models derived within the relativistic mean field approach. For each model, we determine the β -stable EOS and then the corresponding neutron star structure by solving the equations of hydrostatic equilibrium in general relativity. In addition, we calculate the tidal deformability parameters for the two neutron stars and discuss the results of our calculations in connection with the constraints obtained from the gravitational wave signal in GW170817. We find that the tidal deformabilities and radii for the binary’s component neutron stars in GW170817, calculated using a recent microscopic EOS model proposed by the present authors, are in very good agreement with those derived by gravitational waves data.

scholarly journals Thermal luminosities of cooling neutron stars

2020 ◽  
Vol 496 (4) ◽  
pp. 5052-5071 ◽  
Author(s):  
A Y Potekhin ◽  
D A Zyuzin ◽  
D G Yakovlev ◽  
M V Beznogov ◽  
Yu A Shibanov
Keyword(s):  
Spectral Analysis ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Cooling Curves ◽  
Middle Aged ◽  
Superdense Matter ◽  
Strong Magnetic Fields ◽  
Stellar Core ◽  
Neutron Star Cooling

ABSTRACT Ages and thermal luminosities of neutron stars, inferred from observations, can be interpreted with the aid of the neutron star cooling theory to gain information on the properties of superdense matter in neutron-star interiors. We present a survey of estimated ages, surface temperatures, and thermal luminosities of middle-aged neutron stars with relatively weak or moderately strong magnetic fields, which can be useful for these purposes. The catalogue includes results selected from the literature, supplemented with new results of spectral analysis of a few cooling neutron stars. The data are compared with the theory. We show that overall agreement of theoretical cooling curves with observations improves substantially for models where neutron superfluidity in stellar core is weak.

scholarly journals The second Maxwell’s relativistic equations of a rapidaly rotating neutron star, based on ZAMO framework (zero angular momentum observers)

2017 ◽  
Vol 1 (1) ◽  
pp. 13
Author(s):  
Atsnaita Yasrina ◽  
Nugroho Adi Pramono ◽  
Eny Latifah ◽  
Hari Wisodo
Keyword(s):  
Angular Momentum ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Differential Equations ◽  
Neutron Stars ◽  
Maxwell’S Equation ◽  
Rotating Star ◽  
Fundamental Equations ◽  
Relativistic Equations ◽  
Maxwell's Equation

<p class="Abstract">The second Maxwell’s relativistic equations of a rapidaly rotating neutron star, based on ZAMO framework (Zero Angular Momentum Observers) has been formulated. The formulations obtained were epresented by differential equations in the radial, polar, and azimuthal components. The ZAMO basis is implemented because the neutron star reviewed as a rotating star. The second Maxwell’s equation is important to use as one of the fundamental equations to formulate relativistic magnetic fields dynamics of the neutron stars that rotate rapidly.</p>

scholarly journals SGRs and AXPs: Evidence for Delayed Amplification of Magnetic Field after Neutron Star Formation?

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Denis Leahy ◽  
Rachid Ouyed
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Birth Rate ◽  
Massive Stars ◽  
Robust Estimator ◽  
High Magnetic Fields ◽  
Field Amplification ◽  
Kolmogorov Smirnov

We present new analysis of the birth rate of AXPs and SGRS and their associated SNRs. Using Kolmogorov-Smirnov statistics together with parametric fits based on a robust estimator, we find a birth rate of ∼1/(1000 years) for AXPs/SGRs and their associated SNRs. These high rates suggest that all massive stars (greater than ∼(23–32)M⊙) give rise to remnants with magnetar-like fields. Observations indicate a limited fraction of high magnetic fields in these progenitors; thus our study is suggestive of magnetic field amplification. Dynamo mechanisms during the birth of the neutron stars require spin rates much faster than either observations or theory indicate. We propose that massive stars produce neutron stars with normal (∼1012 G) magnetic fields, which are then amplified to1014-1015 G after a delay of hundreds of years. The amplification is speculated to be a consequence of color ferromagnetism and to occur with a delay after the neutron star core reaches quark deconfinement density (i.e., the quark-nova scenario). The delayed amplification allows one to interpret simultaneously the high birth rate and high magnetic fields of AXPs/SGRs and their link to massive stars.

scholarly journals Neutron stars velocities and magnetic fields

2018 ◽  
Vol 172 ◽  
pp. 07002
Author(s):  
Daryel Manreza Paret ◽  
A. Perez Martinez ◽  
Alejandro. Ayala ◽  
G. Piccinelli ◽  
A. Sanchez
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Strange Quark ◽  
Chemical Potential ◽  
Strange Quark Matter ◽  
Strong Magnetic Fields ◽  
Stars Velocities ◽  
Anisotropic Emission

We study a model that explain neutron stars velocities due to the anisotropic emission of neutrinos. Strong magnetic fields present in neutron stars are the source of the anisotropy in the system. To compute the velocity of the neutron star we model its core as composed by strange quark matter and analice the properties of a magnetized quark gas at finite temperature and density. Specifically we have obtained the electron polarization and the specific heat of magnetized fermions as a functions of the temperature, chemical potential and magnetic field which allow us to study the velocity of the neutron star as a function of these parameters.

scholarly journals Recycled pulsars with multipolar magnetospheres from accretion-induced magnetic burial

2020 ◽  
Vol 499 (3) ◽  
pp. 3243-3254
Author(s):  
A G Suvorov ◽  
A Melatos
Keyword(s):  
Magnetic Field ◽  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Field Line ◽  
Dipole Field ◽  
Multipole Moments ◽  
Millisecond Pulsars ◽  
The Magnetic Field ◽  
Field Strengths

ABSTRACT Many millisecond pulsars are thought to be old neutron stars spun up (‘recycled’) during an earlier accretion phase. They typically have relatively weak (≲109 G) dipole field strengths, consistent with accretion-induced magnetic burial. Recent data from the Neutron Star Interior Composition Explorer indicate that hotspots atop the recycled pulsar PSR J0030–0451 are not antipodal, so that the magnetic field cannot be that of a centred dipole. In this paper it is shown that multipolarity is naturally expected in the burial scenario because of equatorial field line compression. Grad–Shafranov equilibria are constructed to show how magnetic multipole moments can be calculated in terms of various properties, such as the amount of accreted mass and the crustal equation of state.

scholarly journals Evolution of thermally generated neutron-star magnetic Fields

1992 ◽  
Vol 128 ◽  
pp. 46-48
Author(s):  
Roger W. Romani ◽  
Lars E. Hernquist
Keyword(s):  
Neutron Star ◽  
Magnetic Fields ◽  
Neutron Stars ◽  
Magnetic Dipole ◽  
Thermal Evolution ◽  
Magnetic Moments ◽  
New Model ◽  
Wide Range ◽  
Theoretical Evidence ◽  
Hubble Time

AbstractStrongly magnetized neutron stars are believed to underlie a variety of astrophysical systems, although conflicting observational and theoretical evidence has led to debate on the origin and stability of these magnetic fields. Here we describe a new model of neutron star magnetic moments, assuming that the fields are generated at birth and following their evolution to ages as large as the Hubble time. With realistic thermal evolution and conductivities, isolated neutron stars will maintain large magnetic dipole fields. As suggested elsewhere field modification under mass accretion might lead to torque decay. We identify an operative mechanism for this process; the results of this unified picture are in agreement with observations of a wide range of neutron star systems.

scholarly journals Neutron Star Atmospheres

2000 ◽  
Vol 177 ◽  
pp. 613-618
Author(s):  
George G. Pavlov ◽  
V. E. Zavlin
Keyword(s):  
Neutron Star ◽  
Magnetic Fields ◽  
Thermal Radiation ◽  
Neutron Stars ◽  
Optical Radiation ◽  
Superdense Matter ◽  
X Ray ◽  
Fundamental Properties ◽  
Surface Temperatures ◽  
Thin Plasma

AbstractProperties of the thermal radiation emitted by neutron stars (NSs) are determined by thin plasma layers (atmospheres) at their surfaces. The NS atmospheres are very different from those of usual stars due to the immense gravity and huge magnetic fields. Current models of hydrogen NS atmospheres show that the spectra deviate substantially from blackbody spectra of the same temperatures. Comparison of the model spectra with recent observations of soft X-ray and UV-optical radiation of NSs yields the surface temperatures considerably lower than those obtained from the blackbody fits. This conclusion have important implications for theories of NS cooling and for understanding fundamental properties of the superdense matter in the NS interiors.

Sign in / Sign up

Export Citation Format

Share Document