Stiffness effects on the dynamics of the bar-mode instability of neutron stars in full general relativity

Löffler, Frank; Pietri, R. De; Feo, Alessandra; Maione, Francesco; Franci, Luca

doi:10.1103/physrevd.91.064057

Cited by 19 publications

(26 citation statements)

References 48 publications

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“…The latter condition is indeed approximately reached at the end of the presented simulations. These quantities are defined in terms of the two vectors ξ µ (t) = (1, 0, 0, 0) and ξ µ (φ) = (0, cos(φ), sin(φ), 0) (see 8), and are the same that were also used in [22,23] to characterize the properties of isolated rotating stars. Namely:…”

Section: Models Resulting In Collapse To a Black Holementioning

confidence: 99%

“…Also shown are two often-used isentropic EOS with P = Kρ Γ , Γ ∈ {2.75, 3.00}. These can be seen as a singlepiece approximant of the same SLy EOS (see [22,23]), and have been used for test cases here. The exact parameters of the seven-segment isentropic polytropic approximant are shown in Table I and, as can be seen in the panels of Fig.…”

Section: Initial Models and Numerical Methodsmentioning

confidence: 99%

“…• In contrast to [21] and [22,23] we reconstruct instead of the three-velocity the product of the threevelocity and the Lorentz factor to prevent artificial velocities exceeding the speed of light due to numerical errors.…”

Section: Initial Models and Numerical Methodsmentioning

confidence: 99%

“…This code is auto-generated by Mathematica using Kranc [38][39][40], implementing the Einstein equations via a 3 + 1−dimensional split using the BSSN-NOK formalism [15][16][17][18][19] and CCZ4 [20] All the main properties used in the deployed code are described in much more detail in [23] for the Einstein Toolkit in general, in [36] for especially some details about the hydrodynamics, and in [22,23] for similar usage in previous work. In particular:…”

Section: Initial Models and Numerical Methodsmentioning

confidence: 99%

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Modeling equal and unequal mass binary neutron star mergers using public codes

et al. 2016

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We present three-dimensional simulations of the dynamics of binary neutron star (BNS) mergers from the late stage of the inspiral process up to ∼ 20 ms after the system has merged, either to form a hyper-massive neutron star (NS) or a rotating black hole (BH). We investigate five equalmass models of total gravitational mass 2.207, 2.373, 2.537, 2.697 and 2.854 M , respectively; and four unequal mass models with M ADM 2.53 M and q 0.94, 0.88, 0.83, and 0.77 (whereis the mass ratio). We use a semi-realistic equation of state (EOS), namely the seven-segment piece-wise polytropic SLyPP with a thermal component given by Γ th = 1.8. We have also compared the resulting dynamics (for one model) using both, the BSSN-NOK and CCZ4 methods for the evolution of the gravitational sector, and also different reconstruction methods for the matter sector, namely PPM, WENO and MP5. Our results show agreement and high resolution, but superiority of BSSN-NOK supplemented by WENO reconstruction at lower resolutions.One of the important characteristics of the present investigation is that for the first time, it has been done using only publicly available open source software: the Einstein Toolkit code, deployed for the dynamical evolution; and the LORENE code, for the generation of the initial models. All of the source code and parameters used for the simulations have been made publicly available. This not only makes it possible to re-run and re-analyze our data, but also enables others to directly build upon this work for future research.

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Section: Models Resulting In Collapse To a Black Holementioning

confidence: 99%

Section: Initial Models and Numerical Methodsmentioning

confidence: 99%

Section: Initial Models and Numerical Methodsmentioning

confidence: 99%

Section: Initial Models and Numerical Methodsmentioning

confidence: 99%

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Modeling equal and unequal mass binary neutron star mergers using public codes

et al. 2016

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“…As noted in the introduction, the state of the system in the post-merger phase is a single (excited) differentially rotating neutron star with a non trivial rotational profile. The remnant may be subject to various instabilities, namely the dynamical bar-mode instability (see [103][104][105] and references therein), the secular Chandrasekhar-Friedman-Schutz (CFS) instability [39,40] and shear instabilities that can develop in differentially rotating stars (see e.g. [106] and references therein).…”

Section: F Corotation and Mode Revivalmentioning

confidence: 99%

Numerical-relativity simulations of long-lived remnants of binary neutron star mergers

et al. 2020

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We analyze the properties of the gravitational wave signal emitted after the merger of a binary neutron star system when the remnant survives for more than a 80 ms (and up to 140 ms). We employ four different piecewise polytropic equations of state supplemented by an ideal fluid thermal component. We find that the post-merger phase can be subdivided into three phases: an early post-merger phase (where the quadrupole mode and a few subdominant features are active), the intermediate post-merger phase (where only the quadrupole mode is active) and the late post-merger phase (where convective instabilities trigger inertial modes). The inertial modes have frequencies somewhat smaller than the quadrupole modes. In one model, we find an interesting association of a corotation of the quadrupole mode in parts of the star with a revival of its amplitude. The gravitational wave emission of inertial modes in the late post-merger phase is concentrated in a narrow frequency region and is potentially detectable by the planned third-generation detectors. This allows for the possibility of probing not only the cold part of the equation of state, but also its dependence on finite temperature. In view of these results, it will be important to investigate the impact of various type of viscosities on the potential excitation of inertial modes in binary neutron star merger remnants.PACS numbers: 04.25.D-, 04.40. Dg, 95.30.Lz, 97.60.Jd

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Rotating stars in relativity

2017

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Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on equilibrium properties and on nonaxisymmetric oscillations and instabilities in f-modes and r-modes have been updated. Several new sections have been added on equilibria in modified theories of gravity, approximate universal relationships, the one-arm spiral instability, on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity including both hydrodynamic and magnetohydrodynamic studies of these objects.

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Stiffness effects on the dynamics of the bar-mode instability of neutron stars in full general relativity

Cited by 19 publications

References 48 publications

Modeling equal and unequal mass binary neutron star mergers using public codes

Modeling equal and unequal mass binary neutron star mergers using public codes

Numerical-relativity simulations of long-lived remnants of binary neutron star mergers

Rotating stars in relativity

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