scholarly journals Gravitational Radiation by a Collapsing Rotating Stellar Core

1986 ◽  
Vol 7 ◽  
pp. 641-643
Author(s):  
Yu Yunqiang
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Neutron Star ◽  
Gravitational Radiation ◽  
Hole Size ◽  
Initial Ratio ◽  
Sharp Reduction ◽  
Initial Value ◽  
Stellar Core ◽  
The Core

AbstractThe reduction of the ratio between specific angular momentum and mass (a/m) due to gravitational radiation has been investigated for a model of collapsing rotating stellar core in a post-newtonian scheme. Results show that if the initial value of the ratio is significantly greater than one, it tends towards one and if the initial ratio is nearly one, no sharp reduction happens as the core collapses to the neutron star or black hole size.

Properties of dynamical space-times

2018 ◽  
Author(s):  
Michele Maggiore
Keyword(s):  
General Relativity ◽  
Black Hole ◽  
Angular Momentum ◽  
Gravitational Radiation ◽  
Hamiltonian Formulation ◽  
Black Hole Mass ◽  
Adm Mass ◽  
Binary Black Hole

An introduction to advanced tools of General Relativity, later used in the study of binary black-hole coalescences. Hamiltonian formulation of General Relativity, ADM mass and angular momentum, irreducible black-hole mass, Newman-Penrose scalars and gravitational radiation.

scholarly journals GW200115: A Nonspinning Black Hole–Neutron Star Merger

2021 ◽  
Vol 922 (1) ◽  
pp. L14
Author(s):  
Ilya Mandel ◽  
Rory J. E. Smith
Keyword(s):  
Black Hole ◽  
Angular Momentum ◽  
Neutron Star ◽  
Gravitational Waves ◽  
Orbital Angular Momentum ◽  
A Priori ◽  
Natural Consequence ◽  
Black Hole Spin ◽  
Large Black Hole ◽  
Star Binary

Abstract GW200115 was the second merger of a black hole and a neutron star confidently detected through gravitational waves. Inference on the signal allows for a large black hole spin misaligned with the orbital angular momentum, but shows little support for aligned spin values. We show that this is a natural consequence of measuring the parameters of a black hole–neutron star binary with nonspinning components while assuming the priors used in the LIGO–Virgo–KAGRA analysis. We suggest that, a priori, a nonspinning binary is more consistent with current astrophysical understanding.

scholarly journals Formation and evolution of black hole and accretion disk in collapse of massive stellar cores

2011 ◽  
Vol 7 (S279) ◽  
pp. 305-308
Author(s):  
Yuichiro Sekiguchi
Keyword(s):  
Shock Wave ◽  
General Relativity ◽  
Black Hole ◽  
Neutron Star ◽  
Kinetic Energy ◽  
Initial Condition ◽  
The Core ◽  
Torus Surface ◽  
Formation And Evolution ◽  
Temperature Equation

AbstractWe describe the results of our numerical simulations of the collapse of a massive stellar core to a BH, performed in the framework of full general relativity incorporating finite-temperature equation of state and neutrino cooling. We adopt a 100 M⊙ presupernova model calculated by Umeda & Nomoto (2008), which has a massive core with a high value of entropy per baryon. Changing the degree of rotation for the initial condition, we clarify the dependence of the outcome on this. When the rotation is rapid enough, the shock wave formed at the core bounce is deformed to be a torus-like shape. Then, the infalling matter is accumulated in the central region due to the oblique shock at the torus surface, hitting the hypermassive neutron star (HMNS) and dissipating the kinetic energy there. As a result, outflows can be launched. The HMNS eventually collapses to a BH and an accretion torus is formed around it. We also found that the evolution of the BH and torus depends strongly on the rotation initially given.

scholarly journals Closing remarks

2012 ◽  
Vol 8 (S291) ◽  
pp. 345-347
Author(s):  
Jocelyn Bell Burnell
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Gravitational Radiation ◽  
Equivalence Principle ◽  
Main Sequence ◽  
Outer Part ◽  
High Mass ◽  
Close Binary ◽  
Star Forming

This meeting started with a bang, with the announcement of what appears to be another ‘Lorimer burst’. Two more ‘diamond planets’, white dwarf binary companions made of crystalline carbon, quickly followed. This drama in the first session gave way to numerous interesting, surprising results. We still have not found a pulsar orbiting a black hole, but we do have the first triple system with the pulsar in the inner binary and a main sequence star forming the outer part of the binary; it may allow tests of the Equivalence Principle. Another close binary may allow checking for dipolar gravitational radiation. Work on the spin-up of millisecond pulsars is better determining the mass accreted during the spin-up and more sophisticated determination of their ages. Indications of more high mass (~2M⊙) pulsars will allow constraints to be placed on the Equation of State for a neutron star. As was remarked, ‘We keep finding cool new pulsars wherever we look!’; Duncan Lorimer predicted we would know of 4000 pulsars by 2020, a doubling of the present number.

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