Fastest spinning millisecond pulsars: indicators for quark matter in neutron stars?

Fuente: arXiv
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Main Authors: Gärtlein, Christoph, Sagun, Violetta, Ivanytskyi, Oleksii, Blaschke, David, Lopes, Ilidio
Format: Preprint
Published: 2024
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author Gärtlein, Christoph
Sagun, Violetta
Ivanytskyi, Oleksii
Blaschke, David
Lopes, Ilidio
author_facet Gärtlein, Christoph
Sagun, Violetta
Ivanytskyi, Oleksii
Blaschke, David
Lopes, Ilidio
contents We study rotating hybrid stars, with a particular emphasis on the effect of a deconfinement phase transition on their properties at high spin. Our analysis is based on a hybrid equation of state (EoS) with a phase transition from hypernuclear matter to color-superconducting quark matter, where both phases are described within a relativistic density functional approach. By varying the vector meson and diquark couplings in the quark matter phase, we obtain different hybrid star sequences with varying extension of the quark matter core, ensuring consistency with astrophysical constraints from mass, radius and tidal deformability measurements. As a result, we demonstrate the impact of an increasing rotational frequency on the maximum gravitational mass, the central energy density of compact stars, the appearance of the quasi-radial oscillations and non-axisymmetric instabilities. We demonstrate that for the most favorable parameter sets with a strong vector coupling, hybrid star configurations with color superconducting quark matter core can describe the fastest spinning and heaviest galactic neutron star (NS) J0952-0607, while it is out of reach for the purely hadronic hypernuclear star configuration. We also revise the previously proposed empirical relation between the Kepler frequency, gravitational mass, and radius of non-rotating NSs, obtained based on the assumption that all NSs, up to the heaviest, are hadronic. We show how the phase transition to quark matter alters this relation and, consequently, the constraints on the dense matter EoS. Our findings reveal that incorporating the hybrid EoS has significant implications for the constraints on the properties of strongly interacting matter and NSs, placing the upper limit on $R_{1.4} \leq 14.90$ km and $R_{0.7}<11.49$ km (considering 716 Hz frequency limit from J1748+2446ad) and $R_{1.4}\leq$11.90~km (for 1000 Hz).
format Preprint
id arxiv_https___arxiv_org_abs_2412_07758
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Fastest spinning millisecond pulsars: indicators for quark matter in neutron stars?
Gärtlein, Christoph
Sagun, Violetta
Ivanytskyi, Oleksii
Blaschke, David
Lopes, Ilidio
Nuclear Theory
High Energy Astrophysical Phenomena
High Energy Physics - Phenomenology
We study rotating hybrid stars, with a particular emphasis on the effect of a deconfinement phase transition on their properties at high spin. Our analysis is based on a hybrid equation of state (EoS) with a phase transition from hypernuclear matter to color-superconducting quark matter, where both phases are described within a relativistic density functional approach. By varying the vector meson and diquark couplings in the quark matter phase, we obtain different hybrid star sequences with varying extension of the quark matter core, ensuring consistency with astrophysical constraints from mass, radius and tidal deformability measurements. As a result, we demonstrate the impact of an increasing rotational frequency on the maximum gravitational mass, the central energy density of compact stars, the appearance of the quasi-radial oscillations and non-axisymmetric instabilities. We demonstrate that for the most favorable parameter sets with a strong vector coupling, hybrid star configurations with color superconducting quark matter core can describe the fastest spinning and heaviest galactic neutron star (NS) J0952-0607, while it is out of reach for the purely hadronic hypernuclear star configuration. We also revise the previously proposed empirical relation between the Kepler frequency, gravitational mass, and radius of non-rotating NSs, obtained based on the assumption that all NSs, up to the heaviest, are hadronic. We show how the phase transition to quark matter alters this relation and, consequently, the constraints on the dense matter EoS. Our findings reveal that incorporating the hybrid EoS has significant implications for the constraints on the properties of strongly interacting matter and NSs, placing the upper limit on $R_{1.4} \leq 14.90$ km and $R_{0.7}<11.49$ km (considering 716 Hz frequency limit from J1748+2446ad) and $R_{1.4}\leq$11.90~km (for 1000 Hz).
title Fastest spinning millisecond pulsars: indicators for quark matter in neutron stars?
topic Nuclear Theory
High Energy Astrophysical Phenomena
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2412.07758