Measuring the basic parameters of neutron stars using model atmospheres

Suleimanov, V.; Poutanen, Juri; Klochkov, D.; Werner, K.

doi:10.1140/epja/i2016-16020-7

Cited by 35 publications

(38 citation statements)

References 77 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The radius of the 1.4M NS is about 12 km, agreeing with the analysis of NS data in [67] and with a recent analysis using the cooling tail method [68], see also Ref. [9] and the contribution to this volume [69].…”

Section: Equation Of Statesupporting

confidence: 90%

“…The DD2vex family of EoS [71] has been used as a basis for a Bayesian M-R analysis in order to extract the most probable EoS behaviour at high densities [80], Applying the constraint for the nearest millisecond pulsar PSR J0437-4715 [53,70] which yields rather large radii ∼ 15 km, in this analysis the stiffest possible hadronic EoS supporting NS with large radii get selected as the most probable ones. This large radius constraint has a preference over other results for the radii since its analysis is not flawed by the uncertainties due to unknown atmospheric composition [81] or controversial interpretation of data from X-ray bursters, see the corresponding contributions to this volume [69,82]. One of those stiffest possible EoS is DD2vex, which we will exploit in the given work, with a van-der-Waals excluded volume parameter v = 16πr 3 N /3 = 4.0 fm 3 that corresponds to a nucleon radius of r N 0.6 fm.…”

Section: Equation Of Statementioning

confidence: 99%

See 1 more Smart Citation

Influence of the stiffness of the equation of state and in-medium effects on the cooling of compact stars

2016

View full text Add to dashboard Cite

Abstract. Measurements of the low masses for the pulsar PSR J0737-3039B, for the companion of PSR J1756-2251 and for the companion of PSR J0453+1559 on the one hand and of the high masses for the pulsars PSR J1614-2230 and PSR J0348-0432 on the other demonstrate the existence of compact stars with masses in a broad range from 1.2 to 2 M . The most massive of these objects might be hybrid stars. To fulfill the constraint Mmax > 2 M with a reserve we exploit the stiff DD2 hadronic equation of state (EoS) without and with excluded volume (DD2vex) correction, which produce maximum neutron star masses of Mmax = 2.43 M and 2.70 M , respectively. We show that the stiffness of the EoS does not preclude an explanation of the whole set of cooling data within "nuclear medium cooling" scenario for compact stars by a variation of the star masses. We select appropriate proton gap profiles from those exploited in the literature and allow for a variation of the effective pion gap controlling the efficiency of the medium modified Urca process. However, we suppress the possibility of pion condensation. In general, the stiffer the EoS the steeper a decrease with density of the effective pion gap is required. Results are compared with previously obtained ones for the HDD EoS for which Mmax = 2.06 M . The cooling of the compact star in the supernova remnant Cassiopeia A (Cas A) is explained mainly by an efficient medium modified Urca process. To explain a > ∼ 2.5% decline of the cooling curve for Cas A, as motivated by an analysis of the ACIS-S instrument data, together with other cooling data exploiting the DD2 EoS a large proton gap at densities n < ∼ 2n0 is required vanishing for n > ∼ 2.5 n0, where n0 is the saturation nuclear density. A smaller decline, as it follows from an analysis of the HRC-S instrument data, is explained with many choices of parameters. With the DD2vex EoS and using an effective pion gap steeper decreasing with the density and/or a proton gap shifted to smaller densities we are also able to reproduce both a strong decline compatible with ACIS-S data and HRC-S instrument data. The mass of Cas A is estimated as 1.6 − 1.9 M , above the value 1.5 M , which we have evaluated with the softer HDD equation of state. Different mass choices for the hottest object XMMU J173203.3-344518 are discussed. We make general remarks also on hybrid star cooling and on its dependence on the stiffness of the hadronic EoS.PACS. 97.60.Jd Neutron stars -95.30.Cq Elementary particle processes -26.60-c Nuclear matter aspects of neutron stars

show abstract

Section: Equation Of Statesupporting

confidence: 90%

Section: Equation Of Statementioning

confidence: 99%

Influence of the stiffness of the equation of state and in-medium effects on the cooling of compact stars

2016

View full text Add to dashboard Cite

show abstract

“…For SU(3) NJL, the smallest radius obtained is 13.35 km above the 10.1-11.1 km prediction of [49] from the analysis of spectroscopic radius measurements during thermonuclear bursts or in quiescence or even the 12.1 AE 1.1 km obtained in [50] from experimental constraints and causality restrictions. However, in [51] radii above 13 km were obtained for X-ray bursting NS and in [52] it has been shown that causality together with the 2 M ⊙ constraints imposes R > 10.7 km. For a recent review of the current status of measurements of radius of neutron stars see [53].…”

Section: B the Role Of Strangenessmentioning

confidence: 99%

Two-solar-mass hybrid stars: A two model description using the Nambu–Jona-Lasinio quark model

2016

View full text Add to dashboard Cite

Hybrid stars with a quark phase described by the Nambu-Jona-Lasinio model are studied. The hadronquark model used to determine the stellar matter equation of state favors the appearance of quark matter: the coincidence of the deconfinement and chiral transitions and a low vacuum constituent quark mass. These two properties are essential to build equations of state that predict pure quark matter in the center of neutron stars. The effect of vector-isoscalar and vector-isovector terms is discussed, and it is shown that the vectorisoscalar terms are necessary to describe 2 M ⊙ hybrid stars, and the vector-isovector terms result in larger quark cores and a smaller deconfinement density.

show abstract

“…1 in Kajava et al 2014 andSuleimanov et al 2016 for the interpretation). It should also be kept in mind that Fe emission features are caused by gas that is only partly ionized; it is possible that the accretion flow extends further in, where Fe is fully Fig.…”

Section: Additional Notes On Reflection and Spectral Featuresmentioning

confidence: 99%

Accretion Disks and Coronae in the X-Ray Flashlight

et al. 2017

View full text Add to dashboard Cite

Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burning and produce a bright flash of X-ray emission called a Type-I X-ray burst. Such events are very common; thousands have been observed to date from over a hundred accreting neutron stars. The intense, often Eddington-limited, radiation generated in these thermonuclear explosions can have a discernible effect on the surrounding accretion flow that consists of an accretion disk and a hot electron corona. Type-I X-ray bursts can there- fore serve as direct, repeating probes of the internal dynamics of the accretion process. In this work we review and interpret the observational evidence for the impact that Type-I X-ray bursts have on accretion disks and coronae. We also provide an outlook of how to make further progress in this research field with prospective experiments and analysis techniques, and by exploiting the technical capabilities of the new and concept X-ray missions ASTROSAT, NICER, Insight-HXMT, eXTP, and STROBE-X.

show abstract

Measuring the basic parameters of neutron stars using model atmospheres

Cited by 35 publications

References 77 publications

Influence of the stiffness of the equation of state and in-medium effects on the cooling of compact stars

Influence of the stiffness of the equation of state and in-medium effects on the cooling of compact stars

Two-solar-mass hybrid stars: A two model description using the Nambu–Jona-Lasinio quark model

Accretion Disks and Coronae in the X-Ray Flashlight

Contact Info

Product

Resources

About