Download or read book Universal Relations for Binary Neutron Star Mergers with Long lived Remnants written by Praveen Manoharan and published by Springer Nature. This book was released on 2022-03-28 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last 25 years, an extensive body of work has developed various equation of state independent - or (approximately) universal - relations that allow for the inference of neutron star parameters from gravitational wave observations. These works, however, have mostly been focused on singular neutron stars, while our observational efforts at the present, and in the near future, will be focused on binary neutron star (BNS) mergers. In light of these circumstances, the last five years have also given rise to more attempts at developing universal relations that relate BNS pre-merger neutron stars to stellar parameters of the post-merger object, mostly driven by numerical relativity simulations. In this thesis a first attempt at perturbatively deriving universal relations for binary neutron star mergers with long-lived neutron star remnants is presented. The author succeeds in confirming previous results relating pre-merger binary tidal deformabilities to the f-mode frequency of the post-merger object. Combining this result with recent advances of computing the f-mode frequency of fast rotating neutron stars, he also derives a combined relation that relates the pre-merger binary tidal deformability of a BNS to the effective compactness of a long-lived neutron star remnant. Finally, he also proposes a direct relation between these quantities with improved accuracy.

Download or read book Handbook of Gravitational Wave Astronomy written by Cosimo Bambi and published by Springer Nature. This book was released on 2022-07-02 with total page 1895 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook provides an updated comprehensive description of gravitational wave astronomy. In the first part, it reviews gravitational wave experiments, from ground and space based laser interferometers to pulsar timing arrays and indirect detection from the cosmic microwave background. In the second part, it discusses a number of astrophysical and cosmological gravitational wave sources, including black holes, neutron stars, possible more exotic objects, and sources in the early Universe. The third part of the book reviews the methods to calculate gravitational waveforms. The fourth and last part of the book covers techniques employed in gravitational wave astronomy data analysis. This book represents both a valuable resource for graduate students and an important reference for researchers in gravitational wave astronomy.

Download or read book Advanced Interferometric Gravitational wave Detectors In 2 Volumes written by Grote Hartmut and published by World Scientific. This book was released on 2019-03-25 with total page 808 pages. Available in PDF, EPUB and Kindle. Book excerpt: The detection of gravitational waves in 2015 has been hailed a scientific breakthrough and one of the most significant scientific discoveries of the 21st century. Gravitational-wave physics and astronomy are emerging as a new frontier in understanding the universe.Advanced Interferometric Gravitational-Wave Detectors brings together many of the world's top experts to deliver an authoritative and in-depth treatment on current and future detectors. Volume I is devoted to the essentials of gravitational-wave detectors, presenting the physical principles behind large-scale precision interferometry, the physics of the underlying noise sources that limit interferometer sensitivity, and an explanation of the key enabling technologies that are used in the detectors. Volume II provides an in-depth look at the Advanced LIGO and Advanced Virgo interferometers, as well as examining future interferometric detector concepts. This two-volume set will provide students and researchers the comprehensive background needed to understand gravitational-wave detectors.

Download or read book The Black Hole Neutron Star Binary Merger in Full General Relativity written by Koutarou Kyutoku and published by Springer Science & Business Media. This book was released on 2013-01-11 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a systematic study of the orbital evolution, gravitational wave radiation, and merger remnant of the black hole–neutron star binary merger in full general relativity for the first time. Numerical-relativity simulations are performed using an adaptive mesh refinement code, SimulAtor for Compact objects in Relativistic Astrophysics (SACRA), which adopts a wide variety of zero-temperature equations of state for the neutron star matter. Gravitational waves provide us with quantitative information on the neutron star compactness and equation of state via the cutoff frequency in the spectra, if tidal disruption of the neutron star occurs before the binary merges. The cutoff frequency will be observed by next-generation laser interferometric ground-based gravitational wave detectors, such as Advanced LIGO, Advanced VIRGO, and KAGRA. The author has also determined that the mass of remnant disks are sufficient for the remnant black hole accretion disk to become a progenitor of short-hard gamma ray bursts accompanied by tidal disruptions and suggests that overspinning black holes may not be formed after the merger of even an extremely spinning black hole and an irrotational neutron star.

Download or read book Inferring the Equation of State with Multi messenger Signals from Binary Neutron Star Mergers written by Matteo Breschi and published by . This book was released on 2023* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The joint detection of the GW170817 and its electromagnetic counterparts was a milestone in multi-messenger astronomy. We investigate the observational constraints on the neutron star equation of state provided by multi-messenger data of binary neutron star mergers, analyzing the gravitational-wave transient GW170817 and its kilonova counterpart AT2017gfo and exploring new scenarios with next-generation gravitational-wave detectors. The LIGO-Virgo data of GW170817 are analyzed using different template models focusing on the implications for neutron star matter properties. We study the systematic tidal errors between current gravitational-wave models finding that waveform systematics dominate over statistical errors at signal-to-noise ratio ≳ 100. We study AT2017gfo using semi-analytical model showing that observational data favor multi-component anisotropic geometries to spherically symmetric profiles. By joining GW170817 and AT2017gfo information with the NICER measurements, we infer the neutron star equation of state constraining the radius of a 1.4M☉ neutron star to 12.39+0.70-0.65 km and the maximum mass MTOV to 2.08+0.16-0.09 M☉ (90% credible level). Finally, we explore future constraints on extreme-matter delivered by postmerger gravitational-waves from binary neutron star merger remnants. These transients can be detected with matched-filtering techniques and numerical-relativity-informed models for signal-to-noise ratios ≳ 7. Postmerger remnants can probe the high-density regimes of the nuclear equation of state, allowing the inference of the maximum neutron star mass MTOV with an accuracy of 12% (90% max credible level). Moreover, postmerger transients can be used to infer the presence of non-nucleonic matter phases through the inference of softening of the equation of state. For particular binary configurations, softening effects of the equation of state can lead to breaking of quasiuniversal properties and earlier collapse into black hole.

Download or read book Binary Neutron Star Merger Simulations written by and published by . This book was released on 2016 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Relativity written by Thomas W. Baumgarte and published by Cambridge University Press. This book was released on 2010-06-24 with total page 717 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aimed at students and researchers entering the field, this pedagogical introduction to numerical relativity will also interest scientists seeking a broad survey of its challenges and achievements. Assuming only a basic knowledge of classical general relativity, the book develops the mathematical formalism from first principles, and then highlights some of the pioneering simulations involving black holes and neutron stars, gravitational collapse and gravitational waves. The book contains 300 exercises to help readers master new material as it is presented. Numerous illustrations, many in color, assist in visualizing new geometric concepts and highlighting the results of computer simulations. Summary boxes encapsulate some of the most important results for quick reference. Applications covered include calculations of coalescing binary black holes and binary neutron stars, rotating stars, colliding star clusters, gravitational and magnetorotational collapse, critical phenomena, the generation of gravitational waves, and other topics of current physical and astrophysical significance.

Download or read book The Fate of the Compact Remnant in Neutron Star Mergers written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Neutron star (binary neutron star and neutron star - black hole) mergers are believed to produce short-duration gamma-ray bursts. They are also believed to be the dominant source of gravitational waves to be detected by the advanced LIGO and the dominant source of the heavy r-process elements in the universe. Whether or not these mergers produce short-duration GRBs depends sensitively on the fate of the core of the remnant (whether, and how quickly, it forms a black hole). In this paper, we combine the results of merger calculations and equation of state studies to determine the fate of the cores of neutron star mergers. Using population studies, we can determine the distribution of these fates to compare to observations. We find that black hole cores form quickly only for equations of state that predict maximum non-rotating neutron star masses below 2.3-2.4 solar masses. If quick black hole formation is essential in producing gamma-ray bursts, LIGO observed rates compared to GRB rates could be used to constrain the equation of state for dense nuclear matter.

Download or read book Binary Neutron Star Merger Remnants as Sources of Cosmic Rays Below the Ankle written by X. Rodrigues and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Threshold to Prompt Collapse of Binary Neutron Star Mergers written by Maximilian Kölsch and published by . This book was released on 2023* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The next observing runs of advanced gravitational-wave detectors will lead to a variety of binary neutron star detections and numerous possibilities for multi-messenger observations of binary neutron star systems. In this context a clear understanding of the merger process and the possibility of prompt black hole formation after merger is important, as the amount of ejected material strongly depends on the merger dynamics. These dynamics are primarily affected by the total mass of the binary, however, the mass ratio also influences the postmerger evolution. To determine the effect of the mass ratio, we investigate the parameter space around the prompt-collapse threshold with a new set of more than 300 fully relativistic simulations, considering 165 different binary configurations. The simulations cover three equations of state and seven mass ratios in the range of 1.0≤q≤1.75, with five to seven simulations of binary systems of different total mass in each case. The threshold mass is determined through an empirical relation based on the collapse-time, which allows us to investigate effects of the mass-ratio on the threshold mass and also on the properties of the remnant system. Furthermore, we model effects of mass ratio and equation of state on tidal parameters of threshold configurations.

Download or read book Aspects of Neutrino Flavor Propagation in Binary Neutron Star Merger Remnants written by Maik Frensel and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rotating Relativistic Stars written by John L. Friedman and published by Cambridge University Press. This book was released on 2013-02-11 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: The masses of neutron stars are limited by an instability to gravitational collapse and an instability driven by gravitational waves limits their spin. Their oscillations are relevant to x-ray observations of accreting binaries and to gravitational wave observations of neutron stars formed during the coalescence of double neutron-star systems. This volume includes more than forty years of research to provide graduate students and researchers in astrophysics, gravitational physics and astronomy with the first self-contained treatment of the structure, stability and oscillations of rotating neutron stars. This monograph treats the equations of stellar equilibrium; key approximations, including slow rotation and perturbations of spherical and rotating stars; stability theory and its applications, from convective stability to the r-mode instability; and numerical methods for computing equilibrium configurations and the nonlinear evolution of their oscillations. The presentation of fundamental equations, results and applications is accessible to readers who do not need the detailed derivations.

Download or read book Compact Binary Merger Simulations in Numerical Relativity written by Francesco Maria Fabbri and published by . This book was released on 2022* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The era of Gravitational Waves Astronomy was launched after the success of the first observation run of the LIGO Scientific Collaboration and the VIRGO Collaboration. The large laser interferometers incredible achievement prompted the need of extensive studies in the field of compact astrophysical objects, such as Black Holes and Neutron Stars. Today, seven years after this event, the field of study underwent a notable expansion, corroborated by the detection of a signal coming from a Binary Neutron Star merger, together with its electro-magnetic counterpart, and, more recently, by the first detections of signals coming from mixed compact binaries, i.e. Black Hole- Neutron Star binaries. In this thesis work we span our attention across different aspects of compact objects mergers, including the inclusion of new physics into the already performing numerical relativity code BAM and the study of specific systems of compact objects. We first explore the treatment of neutrinos in case of Binary Neutron Star mergers and a tool to identify and further analyze regions containing trapped neutrinos, in the hot remnant of such mergers. Neutrinos, play in fact a key role into the rapid processes that characterize the formation of elements in the dynamical ejecta expelled during these catastrophic events. In the following we explore a variety of configurations of mixed compact binary systems. After the development of the new ID code Elliptica, and the steps taken to verify its accuracy, we make use of its capability to evolve sets of physical system with various properties. Exploring the space of parameters we study different spin configurations and magnitudes of single objects and their effects on the merger dynamics.

Download or read book Binary Neutron Star Mergers and Electromagnetic Counterparts h written by Vsevolod Nedora and published by . This book was released on 2022* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In August 2017, a merger of two neutron stars (NSs) was detected for the first time via several carriers. Observed in gravitational waves, as well as in the electromagnetic spectrum, the GW170817 marked the dawn of multi-messenger astronomy for compact object mergers, and shed light on numerous astrophysical aspects of binary neutron star (BNS) mergers and on the properties of matter at supranuclear densities. And yet many questions remain, starting with the outcome of the merger. Was it a massive NS temporarily supported against collapse, or a black hole? How important are BNS mergers in cosmic chemical evolution, i.e., the evolution of spatial and temporal distributions of heavy elements in galaxies? It is known that they enrich their surroundings with very heavy elements, but are they the dominant source of these elements? Modeling these events on the computer, do we understand them correctly, i.e., do our predictions regarding the properties of the ejected matter and its EM signatures agree with the newly gained data? This thesis is dedicated to addressing these questions by means of analyzing a large set of numerical simulations of BNS mergers, performed with state-of-the-art numerical tools, and targeted specifically to GW170817. Employing a suite of postprocessing tools we study the matter dynamics. Special attention is given to matter, ejected from the system during and after merger, so-called ejecta. With the help of a parameterized nucleosynthesis model, we study the final abundances of heavy elements in ejecta, comparing them to solar abundances. Furthermore, we investigate EM emission, powered by the decay of newly synthesized heavy elements, comparing it to the observations of GW170817. Finally, we study the long-term emission of the ejected material as it propagates through the interstellar medium (ISM), via our new numerical tools, comparing the results with a recently detected change in the emission from GW170817.

Download or read book Binary Neutron Star Mergers and Electromagnetic Counterparts h written by Vsevolod Nedora and published by . This book was released on 2022* with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In August 2017, a merger of two neutron stars (NSs) was detected for the first time via several carriers. Observed in gravitational waves, as well as in the electromagnetic spectrum, the GW170817 marked the dawn of multi-messenger astronomy for compact object mergers, and shed light on numerous astrophysical aspects of binary neutron star (BNS) mergers and on the properties of matter at supranuclear densities. And yet many questions remain, starting with the outcome of the merger. Was it a massive NS temporarily supported against collapse, or a black hole? How important are BNS mergers in cosmic chemical evolution, i.e., the evolution of spatial and temporal distributions of heavy elements in galaxies? It is known that they enrich their surroundings with very heavy elements, but are they the dominant source of these elements? Modeling these events on the computer, do we understand them correctly, i.e., do our predictions regarding the properties of the ejected matter and its EM signatures agree with the newly gained data? This thesis is dedicated to addressing these questions by means of analyzing a large set of numerical simulations of BNS mergers, performed with state-of-the-art numerical tools, and targeted specifically to GW170817. Employing a suite of postprocessing tools we study the matter dynamics. Special attention is given to matter, ejected from the system during and after merger, so-called ejecta. With the help of a parameterized nucleosynthesis model, we study the final abundances of heavy elements in ejecta, comparing them to solar abundances. Furthermore, we investigate EM emission, powered by the decay of newly synthesized heavy elements, comparing it to the observations of GW170817. Finally, we study the long-term emission of the ejected material as it propagates through the interstellar medium (ISM), via our new numerical tools, comparing the results with a recently detected change in the emission from GW170817.

Download or read book Towards Simulations of Binary Neutron Star Mergers and Core collapse Supernovae with GenASiS written by Reuben Donald Budiardja and published by . This book was released on 2010 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation describes the current version of GenASiS and reports recent progress in its development. GenASiS is a new computational astrophysics code built for large-scale and multi-dimensional computer simulations of astrophysical phenomena, with primary emphasis on the simulations of neutron star mergers and core-collapse supernovae. Neutron star mergers are of high interest to the astrophysics community because they should be the prodigious source of gravitation waves and the most promising candidates for gravitational wave detection. Neutron star mergers are also thought to be associated with the production of short-duration, hard-spectral gamma-ray bursts, though the mechanism is not well understood. In contrast, core-collapse supernovae with massive progenitors are associated with long-duration, soft-spectral gamma-ray bursts, with the 'collapsar' hypothesis as the favored mechanism. Of equal interest is the mechanism of core-collapse supernovae themselves, which has been in the forefront of many research efforts for the better half of a century but remains a partially-solved mystery. In addition supernovae, and possibly neutron star mergers, are thought to be sites for the r-process nucleosynthesis responsible for producing many of the heavy elements. Until we have a proper understanding of these events, we will have only a limited understanding of the origin of the elements. These questions provide some of the scientific motivations and guidelines for the development of GenASiS. In this document the equations and numerical scheme for Newtonian and relativistic magnetohydrodynamics are presented. A new FFT-based parallel solver for Poisson's equation in GenASiS are described. Adaptive mesh refinement in GenASiS, and a novel way to solve Poisson's equation on a mesh with refinement based on a multigrid algorithm, are also presented. Following these descriptions, results of simulations of neutron star mergers with GenASiS such as their evolution and the gravitational wave signals and spectra that they generate are shown. In the context of core-collapse supernovae, we explore the capacity of the stationary shock instability to generate magnetic fields starting from a weak, stationary, and radial magnetic field in an initially spherically symmetric fluid configuration that models the stalled shock in the post-bounce supernova environment. Our results show that the magnetic energy can be amplified by almost 4 orders of magnitude. The amplification mechanisms for the magnetic fields are then explained.

Download or read book The Physics and Astrophysics of Neutron Stars written by Luciano Rezzolla and published by Springer. This book was released on 2019-01-09 with total page 811 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the recent progress in the physics and astrophysics of neutron stars and, most importantly, it identifies and develops effective strategies to explore, both theoretically and observationally, the many remaining open questions in the field. Because of its significance in the solution of many fundamental questions in nuclear physics, astrophysics and gravitational physics, the study of neutron stars has seen enormous progress over the last years and has been very successful in improving our understanding in these fascinating compact objects. The book addresses a wide spectrum of readers, from students to senior researchers. Thirteen chapters written by internationally renowned experts offer a thorough overview of the various facets of this interdisciplinary science, from neutron star formation in supernovae, pulsars, equations of state super dense matter, gravitational wave emission, to alternative theories of gravity. The book was initiated by the European Cooperation in Science and Technology (COST) Action MP1304 “Exploring fundamental physics with compact stars” (NewCompStar).