scholarly journals One-arm spiral instability in hypermassive neutron stars formed by dynamical-capture binary neutron star mergers

2015 ◽  
Vol 92 (12) ◽  
Author(s):  
Vasileios Paschalidis ◽  
William E. East ◽  
Frans Pretorius ◽  
Stuart L. Shapiro
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Binary Neutron Star ◽  
Spiral Instability

scholarly journals Remnant massive neutron stars of binary neutron star mergers: Evolution process and gravitational waveform

2013 ◽  
Vol 88 (4) ◽  
Author(s):  
Kenta Hotokezaka ◽  
Kenta Kiuchi ◽  
Koutarou Kyutoku ◽  
Takayuki Muranushi ◽  
Yu-ichiro Sekiguchi ◽  
...  
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Evolution Process ◽  
Binary Neutron Star

scholarly journals Relativistic simulations of eccentric binary neutron star mergers: One-arm spiral instability and effects of neutron star spin

2016 ◽  
Vol 93 (2) ◽  
Author(s):  
William E. East ◽  
Vasileios Paschalidis ◽  
Frans Pretorius ◽  
Stuart L. Shapiro
Keyword(s):  
Neutron Star ◽  
Binary Neutron Star ◽  
Spiral Instability

scholarly journals Global simulations of strongly magnetized remnant massive neutron stars formed in binary neutron star mergers

2018 ◽  
Vol 97 (12) ◽  
Author(s):  
Kenta Kiuchi ◽  
Koutarou Kyutoku ◽  
Yuichiro Sekiguchi ◽  
Masaru Shibata
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Binary Neutron Star

scholarly journals SPINAR MODEL FOR BINARY NEUTRON STAR MERGER

2021 ◽  
Vol 53 ◽  
pp. 134-136
Author(s):  
A. R. Chasovnikov ◽  
V. M. Lipunov ◽  
E. S. Gorbovskoy
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Point Of View ◽  
Binary Neutron Star ◽  
Master System ◽  
Robotic Telescopes

We consider the neutron stars mergers from the point of view of the spinar model. We present calculations of the maximum luminosity of merging neutron stars, both total and in optical ranges. The possibility of observing such gamma-ray bursts using the MASTER system of robotic telescopes is also discussed.

scholarly journals Equation of state of dense nuclear matter and neutron star structure from nuclear chiral interactions

2018 ◽  
Vol 609 ◽  
pp. A128 ◽  
Author(s):  
Ignazio Bombaci ◽  
Domenico Logoteta
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Symmetric Nuclear Matter ◽  
Heavy Nuclei ◽  
Hartree Fock ◽  
Binary Neutron Star ◽  
Dense Nuclear Matter ◽  
Three Body

Aims. We report a new microscopic equation of state (EOS) of dense symmetric nuclear matter, pure neutron matter, and asymmetric and β-stable nuclear matter at zero temperature using recent realistic two-body and three-body nuclear interactions derived in the framework of chiral perturbation theory (ChPT) and including the Δ(1232) isobar intermediate state. This EOS is provided in tabular form and in parametrized form ready for use in numerical general relativity simulations of binary neutron star merging. Here we use our new EOS for β-stable nuclear matter to compute various structural properties of non-rotating neutron stars. Methods. The EOS is derived using the Brueckner–Bethe–Goldstone quantum many-body theory in the Brueckner–Hartree–Fock approximation. Neutron star properties are next computed solving numerically the Tolman–Oppenheimer–Volkov structure equations. Results. Our EOS models are able to reproduce the empirical saturation point of symmetric nuclear matter, the symmetry energy Esym, and its slope parameter L at the empirical saturation density n0. In addition, our EOS models are compatible with experimental data from collisions between heavy nuclei at energies ranging from a few tens of MeV up to several hundreds of MeV per nucleon. These experiments provide a selective test for constraining the nuclear EOS up to ~4n0. Our EOS models are consistent with present measured neutron star masses and particularly with the mass M = 2.01 ± 0.04 M⊙ of the neutron stars in PSR J0348+0432.

scholarly journals Constraints on the speed of sound of dense nuclear matter through the tidal deformability of neutron stars

2021 ◽  
Vol 252 ◽  
pp. 05005
Author(s):  
Alkiviadis Kanakis-Pegios ◽  
Polychronis Koliogiannis ◽  
Charalampos Moustakidis
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Speed Of Sound ◽  
Nuclear Physics ◽  
Equations Of State ◽  
Open Problems ◽  
Binary Neutron Star ◽  
Dense Nuclear Matter

One of the greatest interest and open problems in nuclear physics is the upper limit of the speed of sound in dense nuclear matter. Neutron stars, both in isolated and binary system cases, constitute a very promising natural laboratory for studying this kind of problem. This present work is based on one of our recent study, regarding the speed of sound and possible constraints that we can obtain from neutron stars. To be more specific, in the core of our study lies the examination of the speed of sound through the measured tidal deformability of a binary neutron star system (during the inspiral phase). The relation between the maximum neutron star mass scenario and the possible upper bound on the speed of sound is investigated. The approach that we used follows the contradiction between the recent observations of binary neutron star systems, in which the effective tidal deformability favors softer equations of state, while the high measured masses of isolated neutron stars favor stiffer equations of state. In our approach, we parametrized the stiffness of the equation of state by using the speed of sound. Moreover, we used the two recent observations of binary neutron star mergers from LIGO/VIRGO, so that we can impose robust constraints on the speed of sound. Furthermore, we postulate the kind of future measurements that could be helpful by imposing more stringent constraints on the equation of state.

Pan Galactic Gargle Blaster

2019 ◽  
pp. 132-137
Author(s):  
Nicholas Mee
Keyword(s):  
General Relativity ◽  
Neutron Star ◽  
Neutron Stars ◽  
Gravitational Waves ◽  
Gamma Ray ◽  
Great Accuracy ◽  
Gamma Ray Bursts ◽  
Tests Of General Relativity ◽  
Binary Neutron Star

The sources of short gamma ray bursts (GRBs) have been identified with neutron star merger events. Hulse and Taylor discovered the first binary neutron star in 1974. By monitoring the pulsar in this system the orbital characteristics of the system have been determined with great accuracy. This has led to tests of general relativity, including the first confirmation of the existence of gravitational waves. The emission of this radiation is gradually bringing the two neutron stars together. They will collide and merge in about 300 million years.

scholarly journals Multimessenger Binary Mergers Containing Neutron Stars: Gravitational Waves, Jets, and γ-Ray Bursts

2021 ◽  
Vol 8 ◽  
Author(s):  
Milton Ruiz ◽  
Stuart L. Shapiro ◽  
Antonios Tsokaros
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Essential Feature ◽  
Theoretical Understanding ◽  
Binary Neutron Star ◽  
Relativistic Jet ◽  
Binary Mergers ◽  
Γ Ray ◽  
Magnetohydrodynamic Simulations ◽  
The One

Neutron stars (NSs) are extraordinary not only because they are the densest form of matter in the visible Universe but also because they can generate magnetic fields ten orders of magnitude larger than those currently constructed on earth. The combination of extreme gravity with the enormous electromagnetic (EM) fields gives rise to spectacular phenomena like those observed on August 2017 with the merger of a binary neutron star system, an event that generated a gravitational wave (GW) signal, a short γ-ray burst (sGRB), and a kilonova. This event serves as the highlight so far of the era of multimessenger astronomy. In this review, we present the current state of our theoretical understanding of compact binary mergers containing NSs as gleaned from the latest general relativistic magnetohydrodynamic simulations. Such mergers can lead to events like the one on August 2017, GW170817, and its EM counterparts, GRB 170817 and AT 2017gfo. In addition to exploring the GW emission from binary black hole-neutron star and neutron star-neutron star mergers, we also focus on their counterpart EM signals. In particular, we are interested in identifying the conditions under which a relativistic jet can be launched following these mergers. Such a jet is an essential feature of most sGRB models and provides the main conduit of energy from the central object to the outer radiation regions. Jet properties, including their lifetimes and Poynting luminosities, the effects of the initial magnetic field geometries and spins of the coalescing NSs, as well as their governing equation of state, are discussed. Lastly, we present our current understanding of how the Blandford-Znajek mechanism arises from merger remnants as the trigger for launching jets, if, when and how a horizon is necessary for this mechanism, and the possibility that it can turn on in magnetized neutron ergostars, which contain ergoregions, but no horizons.

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