The Mass and Radius of the Neutron Star in 4u 1820–30

Güver, T.; Wroblewski, Patricia; Camarota, Larry; Özel, Feryal

doi:10.1088/0004-637x/719/2/1807

Cited by 247 publications

(229 citation statements)

References 37 publications

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“…[14]. In order to constrain the value of α, the recent measurements of the mass and radius of NSs [17] are used. The region bounded by the thin dash-dotted line in all M-R plots is the 2σ confidence contour based upon these three constraints [18].…”

Section: Resultsmentioning

confidence: 99%

Possible ambiguities in the equation of state for neutron stars

Cheoun

Miyatsu²,

Ryu

et al. 2014

AIP Conference Proceedings

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Abstract.We addressed possible ambiguities on the properties of neutron stars (NSs) estimated in theoretical sides. First, roles of hyperons inside the NS are discussed through various relativistic mean field (RMF) theories. In particular, the extension of SU(6) spin-flavor symmetry to SU(3) flavor symmetry is shown to give rise to the increase of hyperon threshold density, similarly to the Fock term effects in RMF theories. As a result, about 2.0 solar mass is obtained with the hyperons. Second, the effect by the modified f(R) gravity, which leaves a room for the dark energy in the Einstein equation to be taken into account, is discussed for the NS in a strong magnetic field (MF). Our results show that the modified gravity with the Kaluza-Klein electro-magnetism theory expanded in terms of a length scale parameter may reasonably describe the NS in strong MF, so called magnetar. Even the super-soft equation of state is shown to be revived by the modified f(R) gravity.

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Section: Resultsmentioning

confidence: 99%

Possible ambiguities in the equation of state for neutron stars

Cheoun

Miyatsu²,

Ryu

et al. 2014

AIP Conference Proceedings

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“…[23] (Ref. [24]), based on six (eight) neutron star observations of the X-ray bursts [16][17][18][19] and thermal emissions from quiescent low-mass X-ray binaries (LMXBs) in the globular clusters [20][21][22].…”

Section: Numerical Results and Discussionmentioning

confidence: 99%

“…Interestingly, more and more neutron star observations, especially, the accurate measurement of the pulsar J1614-2230 with the mass 1.97 ± 0.04 M ⊙ [15], the astrophysical observations of X-ray bursts [16][17][18][19] and thermal emissions from quiescent low-mass X-ray binaries (LMXBs) in the globular clusters [20][21][22], gradually provide a reliable constraint on the mass-radius relations which is tightly connected to the EoS of neutron star matter. The analysis of these astrophysical observations shows that the radius of a 1.4 solar mass neutron star lies between 10.4 and 12.9 km, independent of assumptions about the composition of the core [23,24].…”

Section: Introductionmentioning

confidence: 99%

Isoscalar-vector interaction and hybrid quark core in massive neutron stars

et al. 2013

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The hadron-quark phase transition in the core of massive neutron stars is studied with a newly constructed two-phase model. For nuclear matter, a nonlinear Walecka type model with general nucleon-meson and meson-meson couplings, recently calibrated by Steiner, Hemper and Fischer, is taken. For quark matter, a modified Polyakov-Nambu-Jona-Lasinio (mPNJL) model, which gives consistent results with lattice QCD data, is used. Most importantly, we introduce an isoscalar-vector interaction in the description of quark matter, and we study its influence on the hadron-quark phase transition in the interior of massive neutron stars. With the constraints of neutron star observations, our calculation shows that the isoscalar-vector interaction between quarks is indispensable if massive hybrids star exist in the universe, and its strength determines the onset density of quark matter, as well as the mass-radius relations of hybrid stars. Furthermore, as a connection with heavy-ioncollision experiments we give some discussions about the strength of isoscalar-vector interaction and its effect on the signals of hadron-quark phase transition in heavy-ion collisions, in the energy range of the NICA at JINR-Dubna and FAIR at GSI-Darmstadt facilities.

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“…Spectroscopic observations of a number of neutron stars during thermonuclear X-ray bursts have led to measurements of their masses and radii. This category includes 4U 1745−248 (Özel et al 2009), 4U 1608−52 (Güver et al 2010a), 4U 1820−30 (Güver et al 2010b), and KS 1731−260 (Özel et al 2012. We convert the posterior likelihood of mass and radius for each neutron star reported in these analyses into a likelihood of mass by integrating over radius as…”

Section: Notesmentioning

confidence: 99%

On the Mass Distribution and Birth Masses of Neutron Stars

Özel

Psaltis

Narayan

et al. 2012

ApJ

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364

274

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We investigate the distribution of neutron star masses in different populations of binaries, employing Bayesian statistical techniques. In particular, we explore the differences in neutron star masses between sources that have experienced distinct evolutionary paths and accretion episodes. We find that the distribution of neutron star masses in non-recycled eclipsing high-mass binaries as well as of slow pulsars, which are all believed to be near their birth masses, has a mean of 1.28 M and a dispersion of 0.24 M . These values are consistent with expectations for neutron star formation in core-collapse supernovae. On the other hand, double neutron stars, which are also believed to be near their birth masses, have a much narrower mass distribution, peaking at 1.33 M , but with a dispersion of only 0.05 M . Such a small dispersion cannot easily be understood and perhaps points to a particular and rare formation channel. The mass distribution of neutron stars that have been recycled has a mean of 1.48 M and a dispersion of 0.2 M , consistent with the expectation that they have experienced extended mass accretion episodes. The fact that only a very small fraction of recycled neutron stars in the inferred distribution have masses that exceed ∼2 M suggests that only a few of these neutron stars cross the mass threshold to form low-mass black holes.

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The Mass and Radius of the Neutron Star in 4u 1820–30

Cited by 247 publications

References 37 publications

Possible ambiguities in the equation of state for neutron stars

Possible ambiguities in the equation of state for neutron stars

Isoscalar-vector interaction and hybrid quark core in massive neutron stars

On the Mass Distribution and Birth Masses of Neutron Stars

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