scholarly journals Equation-of-state dependence of the gravitational-wave signal from the ring-down phase of neutron-star mergers

2012 ◽  
Vol 86 (6) ◽  
Author(s):  
A. Bauswein ◽  
H.-T. Janka ◽  
K. Hebeler ◽  
A. Schwenk
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Gravitational Wave ◽  
State Dependence ◽  
Wave Signal

scholarly journals Waveform systematics in the gravitational-wave inference of tidal parameters and equation of state from binary neutron-star signals

2021 ◽  
Vol 103 (12) ◽  
Author(s):  
Rossella Gamba ◽  
Matteo Breschi ◽  
Sebastiano Bernuzzi ◽  
Michalis Agathos ◽  
Alessandro Nagar
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Gravitational Wave ◽  
Binary Neutron Star

scholarly journals Gravitational-Wave Constraints on the Neutron-Star-Matter Equation of State

2018 ◽  
Vol 120 (17) ◽  
Author(s):  
Eemeli Annala ◽  
Tyler Gorda ◽  
Aleksi Kurkela ◽  
Aleksi Vuorinen
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Gravitational Wave ◽  
Neutron Star Matter

scholarly journals Fundamental physics and the absence of sub-millisecond pulsars

2018 ◽  
Vol 620 ◽  
pp. A69 ◽  
Author(s):  
B. Haskell ◽  
J. L. Zdunik ◽  
M. Fortin ◽  
M. Bejger ◽  
R. Wijnands ◽  
...  
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Equations Of State ◽  
Rotation Frequency ◽  
Hadronic Matter ◽  
Spin Distribution ◽  
Test Models ◽  
State Of Matter

Context. Rapidly rotating neutron stars are an ideal laboratory to test models of matter at high densities. In particular, the maximum rotation frequency of a neutron star depends on the equation of state and can be used to test models of the interior. However, observations of the spin distribution of rapidly rotating neutron stars show evidence for a lack of stars spinning at frequencies higher than f ≈ 700 Hz, well below the predictions of theoretical equations of state. This has generally been taken as evidence of an additional spin-down torque operating in these systems, and it has been suggested that gravitational wave torques may be operating and be linked to a potentially observable signal. Aims. We aim to determine whether additional spin-down torques (possibly due to gravitational wave emission) are necessary, or if the observed limit of f ≈ 700 Hz could correspond to the Keplerian (mass-shedding) break-up frequency for the observed systems, and is simply a consequence of the currently unknown state of matter at high densities. Methods. Given our ignorance with regard to the true equation of state of matter above nuclear saturation densities, we make a minimal physical assumption and only demand causality, that is, that the speed of sound in the interior of the neutron star should be lower than or equal to the speed of light c. We then connected our causally limited equation of state to a realistic microphysical crustal equation of state for densities below nuclear saturation density. This produced a limiting model that gave the lowest possible maximum frequency, which we compared to observational constraints on neutron star masses and frequencies. We also compared our findings with the constraints on the tidal deformability obtained in the observations of the GW170817 event. Results. We rule out centrifugal breakup as the mechanism preventing pulsars from spinning faster than f ≈ 700 Hz, as the lowest breakup frequency allowed by our causal equation of state is f ≈ 1200 Hz. A low-frequency cutoff, around f ≈ 800 Hz could only be possible when we assume that these systems do not contain neutron stars with masses above M ≈ 2 M⊙. This would have to be due either to selection effects, or possibly to a phase transition in the interior of the neutron star that leads to softening at high densities and a collapse to either a black hole or a hybrid star above M ≈ 2 M⊙. Such a scenario would, however, require a somewhat unrealistically stiff equation of state for hadronic matter, in tension with recent constraints obtained from gravitational wave observations of a neutron star merger.

scholarly journals Detecting the Hadron-Quark Phase Transition with Gravitational Waves

Universe ◽  
2019 ◽  
Vol 5 (6) ◽  
pp. 156 ◽  
Author(s):  
Matthias Hanauske ◽  
Luke Bovard ◽  
Elias Most ◽  
Jens Papenfort ◽  
Jan Steinheimer ◽  
...  
Keyword(s):  
Phase Transition ◽  
Neutron Star ◽  
Equation Of State ◽  
Gravitational Wave ◽  
Compact Star ◽  
Binary Neutron Star ◽  
Interesting Part ◽  
Merger Event ◽  
Tidal Deformations ◽  
Quark Phase

The long-awaited detection of a gravitational wave from the merger of a binary neutron star in August 2017 (GW170817) marks the beginning of the new field of multi-messenger gravitational wave astronomy. By exploiting the extracted tidal deformations of the two neutron stars from the late inspiral phase of GW170817, it is now possible to constrain several global properties of the equation of state of neutron star matter. However, the most interesting part of the high density and temperature regime of the equation of state is solely imprinted in the post-merger gravitational wave emission from the remnant hypermassive/supramassive neutron star. This regime was not observed in GW170817, but will possibly be detected in forthcoming events within the current observing run of the LIGO/VIRGO collaboration. Numerous numerical-relativity simulations of merging neutron star binaries have been performed during the last decades, and the emitted gravitational wave profiles and the interior structure of the generated remnants have been analysed in detail. The consequences of a potential appearance of a hadron-quark phase transition in the interior region of the produced hypermassive neutron star and the evolution of its underlying matter in the phase diagram of quantum cromo dynamics will be in the focus of this article. It will be shown that the different density/temperature regions of the equation of state can be severely constrained by a measurement of the spectral properties of the emitted post-merger gravitational wave signal from a future binary compact star merger event.

scholarly journals m=1instability and gravitational wave signal in binary neutron star mergers

2016 ◽  
Vol 94 (4) ◽  
Author(s):  
Luis Lehner ◽  
Steven L. Liebling ◽  
Carlos Palenzuela ◽  
Patrick M. Motl
Keyword(s):  
Neutron Star ◽  
Gravitational Wave ◽  
Wave Signal ◽  
Binary Neutron Star

scholarly journals Gravitational-Wave Asteroseismology as a Tool to Reveal the Equation of State of Relativistic Neutron Stars

2002 ◽  
Vol 185 ◽  
pp. 612-615
Author(s):  
Johannes Ruoff
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Oscillation Modes

AbstractThe equation of state (EOS) is still the big unknown in the physics of neutron stars. An accurate measurement of both the mass and the radius of a neutron star would put severe constraints on the range of possible EOSs. I discuss how the parameters of the oscillation modes of a neutron star, measured from the emitted gravitational waves, can in principle be used to infer its mass and radius, and thus reveal its EOS.

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