Population Clustering as a Signal for Deconfinement in Accreting Compact Stars

Poghosyan, Gevorg; Grigorian, H.; Blaschke, D.

doi:10.1086/319851

Cited by 22 publications

(28 citation statements)

References 19 publications

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“…The proposed limiting mechanisms responsible for this behavior could be gravity-wave emission caused by the r-mode instability, or a small stellar mass quadrupole moment [328,329,330]. As shown here, quark reconfinement may be linked to this phenomenon as well [320,321,325,331] …”

Section: Accreting Neutron Starsmentioning

confidence: 68%

Strange quark matter and compact stars

Weber

2005

Progress in Particle and Nuclear Physics

694

280

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Astrophysicists distinguish between three different types of compact stars. These are white dwarfs, neutron stars, and black holes. The former contain matter in one of the densest forms found in the Universe which, together with the unprecedented progress in observational astronomy, make such stars superb astrophysical laboratories for a broad range of most striking physical phenomena. These range from nuclear processes on the stellar surface to processes in electron degenerate matter at subnuclear densities to boson condensates and the existence of new states of baryonic matter-like color superconducting quark matter-at supernuclear densities. More than that, according to the strange matter hypothesis strange quark matter could be more stable than nuclear matter, in which case neutron stars should be largely composed of pure quark matter possibly enveloped in thin nuclear crusts. Another remarkable implication of the hypothesis is the possible existence of a new class of white dwarfs. This article aims at giving an overview of all these striking physical possibilities, with an emphasis on the astrophysical phenomenology of strange quark matter. Possible observational signatures associated with the theoretically proposed states of matter inside compact stars are discussed as well. They will provide most valuable information about the phase diagram of superdense nuclear matter at high baryon number density but low temperature, which is not accessible to relativistic heavy ion collision experiments.

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Section: Accreting Neutron Starsmentioning

confidence: 68%

Strange quark matter and compact stars

Weber

2005

Progress in Particle and Nuclear Physics

694

280

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“…We put particular emphasis on the possible existence of quark matter inside of rotating neutron stars, known as pulsars. In contrast to non-rotating neutron stars, whose core compositions do not change with time (are frozen in), the type and structure of the matter in the cores of rotating neutron stars depends on the spin frequencies of these stars, which could give rise to observable astrophysical signals of quark deconfinement [18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Quark Deconfinement in Rotating Neutron Stars

et al. 2017

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Abstract:In this paper, we use a three flavor non-local Nambu-Jona-Lasinio (NJL) model, an improved effective model of Quantum Chromodynamics (QCD) at low energies, to investigate the existence of deconfined quarks in the cores of neutron stars. Particular emphasis is put on the possible existence of quark matter in the cores of rotating neutron stars (pulsars). In contrast to non-rotating neutron stars, whose particle compositions do not change with time (are frozen in), the type and structure of the matter in the cores of rotating neutron stars depends on the spin frequencies of these stars, which opens up a possible new window on the nature of matter deep in the cores of neutron stars. Our study shows that, depending on mass and rotational frequency, up to around 8% of the mass of a massive neutron star may be in the mixed quark-hadron phase, if the phase transition is treated as a Gibbs transition. We also find that the gravitational mass at which quark deconfinement occurs in rotating neutron stars varies quadratically with spin frequency, which can be fitted by a simple formula.

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“…Therefore, also suggested signals from the timing behavior of pulsar spin-down [18], frequency clustering [19] or population clustering [20,21] of accreting NSs should not be applicable.…”

Section: Introductionmentioning

confidence: 99%

Unmasking neutron star interiors using cooling simulations

Blaschke

Grigorian

2007

Progress in Particle and Nuclear Physics

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We introduce a new tool for 'unmasking' the composition of neutron star (NS) interiors which is based on the fact that the state of matter at high densities determines the statistics of both NS observables, the temperature-age (TA) data as well as the mass distribution. We use modern cooling simulations to extract distributions of NS masses required to reproduce those of the yet sparse data in the TA plane. By comparing the results with a mass distribution for young, nearby NSs from population synthesis we can sharpen two NS cooling problems. The direct Urca (DU) problem consists in a narrowing of the NS population at the mass value for which the DU process as the most effective cooling mechanism in the hadronic layer of the star can occur. The Vela mass problem is a broadening of the population beyond the range of the typical mass window of 1.1 - 1.5 M_sun. Applying this tool to modern EoS we discuss examples for pure hadronic stars which are in conflict with these constraints while hybrid stars with a color superconducting quark matter core can predict a satisfactory mass distribution, provided the smallest diquark pairing gap has a properly defined density dependence.Comment: 8 pages, 8 figures, Proceedings of the Erice School on 'Radioactive Beams, Nuclear Dynamics and Astrophysics' to be published in 'Prog. Part. Nucl. Phys.

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Population Clustering as a Signal for Deconfinement in Accreting Compact Stars

Cited by 22 publications

References 19 publications

Strange quark matter and compact stars

Strange quark matter and compact stars

Quark Deconfinement in Rotating Neutron Stars

Unmasking neutron star interiors using cooling simulations

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