Dynamical bar-mode instability of differentially rotating stars: effects of equations of state and velocity profiles

Shibata, Masaru; Karino, Shotaro; Eriguchi, Yoshiharu

doi:10.1046/j.1365-8711.2003.06699.x

Cited by 113 publications

(104 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, a new kind of dynamical rotational nonaxisymmetric instability at a value of β much lower than the classical threshold has been discovered both in numerical and perturbative studies (see, e.g., [17,22,25,[79][80][81][82][83][84][85] and references therein). This low-β instability (making the classical MacLaurin instability a "high"-β instability) appears to amplify nonaxisymmetric modes at points where their pattern speed σ m (the eigenfrequency ω m divided by the azimuthal mode order m) coincides with the local angular velocity of the fluid [22,[81][82][83].…”

Section: Rotation Of the Proto-neutron Starmentioning

confidence: 99%

Gravitational wave burst signal from core collapse of rotating stars

et al. 2008

View full text Add to dashboard Cite

We present results from detailed general relativistic simulations of stellar core collapse to a protoneutron star, using two different microphysical nonzero-temperature nuclear equations of state as well as an approximate description of deleptonization during the collapse phase. Investigating a wide variety of rotation rates and profiles as well as masses of the progenitor stars and both equations of state, we confirm in this very general setup the recent finding that a generic gravitational wave burst signal is associated with core bounce, already known as type I in the literature. The previously suggested type II (or "multiple-bounce") waveform morphology does not occur. Despite this reduction to a single waveform type, we demonstrate that it is still possible to constrain the progenitor and postbounce rotation based on a combination of the maximum signal amplitude and the peak frequency of the emitted gravitational wave burst. Our models include to sufficient accuracy the currently known necessary physics for the collapse and bounce phase of core-collapse supernovae, yielding accurate and reliable gravitational wave signal templates for gravitational wave data analysis. In addition, we assess the possiblity of nonaxisymmetric instabilities in rotating nascent proto-neutron stars. We find strong evidence that in an iron core-collapse event the postbounce core cannot reach sufficiently rapid rotation to become subject to a classical bar-mode instability. However, many of our postbounce core models exhibit sufficiently rapid and differential rotation to become subject to the recently discovered dynamical instability at low rotation rates.

show abstract

Section: Rotation Of the Proto-neutron Starmentioning

confidence: 99%

Gravitational wave burst signal from core collapse of rotating stars

et al. 2008

View full text Add to dashboard Cite

show abstract

“…The hypermassive NS is expected to be a non-axisymmetric ellipsoid supported against collapse by a combination of thermal pressure and differential rotation [305] and can delay BH formation for 1 ms to 1 s [305,307]. This phase could wit-ness quite a lot of rotational energy emitted as GWs, with a spectrum that is characteristic of the NS EoS [308,309]. A BH without an accretion disk is not a very likely outcome, but it can happen if M > ∼ 3 M [303, 304,310].…”

Section: Stellar-mass Binariesmentioning

confidence: 99%

“…Analytical and semi-analytical models of NS-NS and NS-BH mergers will be crucial for parameter esti-mation and Bayesian hypothesis testing. This will be a huge challenge for the bar-mode instability regime where the signal does not seem to have any phase coherence (see, e.g., simulations in [308,309]). Even so, accurate modeling of the expected spectrum or time-frequency content of the signal can be useful in understanding the physics of dynamical instabilities.…”

Section: Challengesmentioning

confidence: 99%

Sources of Gravitational Waves: Theory and Observations

Buonanno

Sathyaprakash²

2015

General Relativity and Gravitation

View full text Add to dashboard Cite

“…The j5 models may even reach the threshold of 27% for the high-T /|W | dynamical instability within a few hundred ms of bounce. models already at values of T /|W | of order ∼1% [59,[123][124][125][126]. Hence, this instability is commonly referred to as low-T /|W | instability.…”

Section: Evolution Of the Rotation Rate And Prospects For Rotationmentioning

confidence: 99%

Correlated gravitational wave and neutrino signals from general-relativistic rapidly rotating iron core collapse

et al. 2012

View full text Add to dashboard Cite

We present results from a new set of 3D general-relativistic hydrodynamic simulations of rotating iron core collapse. We assume octant symmetry and focus on axisymmetric collapse, bounce, the early postbounce evolution, and the associated gravitational wave (GW) and neutrino signals. We employ a finite-temperature nuclear equation of state, parameterized electron capture in the collapse phase, and a multi-species neutrino leakage scheme after bounce. The latter captures the important effects of deleptonization, neutrino cooling and heating and enables approximate predictions for the neutrino luminosities in the early evolution after core bounce. We consider 12-M and 40-M presupernova models and systematically study the effects of (i) rotation, (ii) progenitor structure, and (iii) postbounce neutrino leakage on dynamics, GW, and, neutrino signals. We demonstrate, that the GW signal of rapidly rotating core collapse is practically independent of progenitor mass and precollapse structure. Moreover, we show that the effects of neutrino leakage on the GW signal are strong only in nonrotating or slowly rotating models in which GW emission is not dominated by inner core dynamics. In rapidly rotating cores, core bounce of the centrifugally-deformed inner core excites the fundamental quadrupole pulsation mode of the nascent protoneutron star. The ensuing global oscillations (f ∼ 700 − 800 Hz) lead to pronounced oscillations in the GW signal and correlated strong variations in the rising luminosities of antineutrino and heavy-lepton neutrinos. We find these features in cores that collapse to protoneutron stars with spin periods 2.5 ms and rotational energies sufficient to drive hyper-energetic core-collapse supernova explosions. Hence, GW or neutrino observations of a core collapse event could deliver strong evidence for or against rapid core rotation. Joint GW + neutrino observations would allow to make statements with high confidence. Our estimates suggest that the GW signal should be detectable throughout the Milky Way by advanced laser-interferometer GW observatories, but a water-Cherenkov neutrino detector would have to be of near-megaton size to observe the variations in the early neutrino luminosities from a core collapse event at 1 kpc.

show abstract

Dynamical bar-mode instability of differentially rotating stars: effects of equations of state and velocity profiles

Cited by 113 publications

References 23 publications

Gravitational wave burst signal from core collapse of rotating stars

Gravitational wave burst signal from core collapse of rotating stars

Sources of Gravitational Waves: Theory and Observations

Correlated gravitational wave and neutrino signals from general-relativistic rapidly rotating iron core collapse

Contact Info

Product

Resources

About