scholarly journals Gravitational waves from neutron stars and asteroseismology

2018 ◽  
Vol 376 (2120) ◽  
pp. 20170285 ◽  
Author(s):  
Wynn C. G. Ho
Keyword(s):  
Electromagnetic Wave ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Massive Stars ◽  
Supernova Explosion ◽  
Wide Binary ◽  
Fundamental Physics ◽  
Atomic Nuclei ◽  
The Earth

Neutron stars are born in the supernova explosion of massive stars. Neutron stars rotate as stably as atomic clocks and possess densities exceeding that of atomic nuclei and magnetic fields millions to billions of times stronger than those created in laboratories on the Earth. The physical properties of neutron stars are determined by many areas of fundamental physics, and detection of gravitational waves can provide invaluable insights into our understanding of these areas. Here, we describe some of the physics and astrophysics of neutron stars and how traditional electromagnetic wave observations provide clues to the sorts of gravitational waves we expect from these stars. We pay particular attention to neutron star fluid oscillations, examining their impact on electromagnetic and gravitational wave observations when these stars are in a wide binary or isolated system, then during binary inspiral right before merger, and finally at times soon after merger. This article is part of a discussion meeting issue ‘The promises of gravitational-wave astronomy’.

scholarly journals The gravitational-wave physics

2017 ◽  
Vol 4 (5) ◽  
pp. 687-706 ◽  
Author(s):  
Rong-Gen Cai ◽  
Zhoujian Cao ◽  
Zong-Kuan Guo ◽  
Shao-Jiang Wang ◽  
Tao Yang
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Laser Interferometer ◽  
Direct Detection ◽  
Fundamental Physics ◽  
First Order ◽  
Compact Binary ◽  
First Order Phase Transition ◽  
First Order Phase ◽  
The Universe

Abstract The direct detection of gravitational wave by Laser Interferometer Gravitational-Wave Observatory indicates the coming of the era of gravitational-wave astronomy and gravitational-wave cosmology. It is expected that more and more gravitational-wave events will be detected by currently existing and planned gravitational-wave detectors. The gravitational waves open a new window to explore the Universe and various mysteries will be disclosed through the gravitational-wave detection, combined with other cosmological probes. The gravitational-wave physics is not only related to gravitation theory, but also is closely tied to fundamental physics, cosmology and astrophysics. In this review article, three kinds of sources of gravitational waves and relevant physics will be discussed, namely gravitational waves produced during the inflation and preheating phases of the Universe, the gravitational waves produced during the first-order phase transition as the Universe cools down and the gravitational waves from the three phases: inspiral, merger and ringdown of a compact binary system, respectively. We will also discuss the gravitational waves as a standard siren to explore the evolution of the Universe.

scholarly journals Gravitational waves: where we are, where we go

2019 ◽  
Vol 209 ◽  
pp. 01045
Author(s):  
Fulvio Ricci
Keyword(s):  
Gravitational Wave ◽  
Gravitational Waves ◽  
Present Status ◽  
New Physics ◽  
Third Generation ◽  
The Third ◽  
The Earth ◽  
Gravitational Wave Detectors

We review the present status of the Gravitational wave detectors on the Earth, focusing the attention on the present innovations and the longer term perspectives to improve their sensitivity. Then we conclude mentioning few potential searches of new Physics phenomena to be performed with these detectors and those of the third generation.

scholarly journals THE R-MODE INSTABILITY IN ROTATING NEUTRON STARS

2001 ◽  
Vol 10 (04) ◽  
pp. 381-441 ◽  
Author(s):  
NILS ANDERSSON ◽  
KOSTAS D. KOKKOTAS
Keyword(s):  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Binary Systems ◽  
Current Understanding ◽  
Mode Instability ◽  
Spin Evolution ◽  
Astrophysical Significance

In this review we summarize the current understanding of the gravitational-wave driven instability associated with the so-called r-modes in rotating neutron stars. We discuss the nature of the r-modes, the detailed mechanics of the instability and its potential astrophysical significance. In particular we discuss results regarding the spin-evolution of nascent neutron stars, the detectability of r-mode gravitational waves and mechanisms limiting the spin-rate of accreting neutron stars in binary systems.

NEW ASPECTS ON GRAVITATIONAL WAVE EMISSION BY NEUTRON STARS

2004 ◽  
Vol 13 (07) ◽  
pp. 1293-1296 ◽  
Author(s):  
GUILHERME F. MARRANGHELLO ◽  
CÉSAR A. Z. VASCONCELLOS ◽  
JOSÉ A. de FREITAS PACHECO ◽  
MANFRED DILLIG ◽  
HÉLIO T. COELHO
Keyword(s):  
Phase Transition ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Quark Matter ◽  
Inner Core ◽  
Compact Objects ◽  
Wave Emission

We discuss, in this work, new aspects related to the emission of gravitational waves by neutron stars, which undergo a phase transition, from nuclear to quark matter, in its inner core. Such a phase transition would liberate around 1052–53 erg of energy in the form of gravitational waves which, if detected, may shed some light in the structure of these compact objects and provide new insights on the equation of state of nuclear matter.

scholarly journals Population synthesis of accreting neutron stars emitting gravitational waves

2019 ◽  
Vol 488 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Fabian Gittins ◽  
Nils Andersson
Keyword(s):  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Population Synthesis ◽  
Spin Distribution ◽  
Synthetic Populations ◽  
Low Mass ◽  
Wave Emission ◽  
X Ray Binaries ◽  
Production Mechanisms

ABSTRACT The fastest-spinning neutron stars in low-mass X-ray binaries, despite having undergone millions of years of accretion, have been observed to spin well below the Keplerian break-up frequency. We simulate the spin evolution of synthetic populations of accreting neutron stars in order to assess whether gravitational waves can explain this behaviour and provide the distribution of spins that is observed. We model both persistent and transient accretion and consider two gravitational-wave-production mechanisms that could be present in these systems: thermal mountains and unstable rmodes. We consider the case of no gravitational-wave emission and observe that this does not match well with observation. We find evidence for gravitational waves being able to provide the observed spin distribution; the most promising mechanisms being a permanent quadrupole, thermal mountains, and unstable r modes. However, based on the resultant distributions alone, it is difficult to distinguish between the competing mechanisms.

Why Newtonian gravity is an electromagnetic wave

2020 ◽  
Vol 33 (1) ◽  
pp. 23-26
Author(s):  
Nicolus Rotich
Keyword(s):  
Electromagnetic Wave ◽  
Gravitational Waves ◽  
Newtonian Gravity ◽  
Earth Surface ◽  
Speed Of Light ◽  
The Earth ◽  
Planetary Bodies ◽  
The Waves

In this brief communication, we have hypothesized that since Newtonian gravity intimately interacts with classical gravitational waves, it must also be perceivable and mathematically expressible as a wave. It has been shown that Newtonian gravity can be represented as an electromagnetic wave of a particular wavelength <mml:math display="inline"> <mml:mi>λ</mml:mi> </mml:math> , propagating at the speed of light, c and with a radius of <mml:math display="inline"> <mml:mrow> <mml:mi>z</mml:mi> <mml:mo>=</mml:mo> <mml:mi>λ</mml:mi> <mml:mo>/</mml:mo> <mml:mn>2</mml:mn> <mml:mi>π</mml:mi> </mml:mrow> </mml:math> . The waves period is given by T = c/g, and thus acceleration due to gravity is representable as g = cf, where f is position dependent, and thus unique for all orbiting planetary bodies. On the Earth surface, this value is ≅32.71 nHz.

scholarly journals NON-RADIAL OSCILLATIONS OF NEUTRON STARS AND THE DETECTION OF GRAVITATIONAL WAVES

2012 ◽  
Vol 18 ◽  
pp. 48-52 ◽  
Author(s):  
CECILIA CHIRENTI ◽  
PATRICK R. SILVEIRA ◽  
ODYLIO D. AGUIAR
Keyword(s):  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Sensitivity Range ◽  
Wave Emission ◽  
Spherical Detector

We study the non-radial oscillations of relativistic neutron stars, in particular the (fundamental) f-modes, which are believed to be the most relevant for the gravitational wave emission of perturbed isolated stars. The expected frequencies of the f-modes are compared to the sensitivity range of Mario Schenberg, the Brazilian gravitational wave spherical detector.

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.

scholarly journals Gravitational Waves and Neutron Stars

2000 ◽  
Vol 177 ◽  
pp. 727-732
Author(s):  
Bernard F. Schutz
Keyword(s):  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Gravitational Radiation ◽  
First Generation ◽  
Crab Pulsar ◽  
Pulsar Radio ◽  
Better Than

AbstractThe first generation of laser-interferomteric gravitational wave observatories will make intensive searches for gravitational radiation from spinning neutron stars. Sensitivity to a number of possible sources, including the Crab pulsar, will be better than any existing observational limits, and will improve dramatically over the next decade. This paper reviews these developments and expectations, and discusses ways in which pulsar radio astronomers and gravitational wave astronomers can benefit from one another’s work.

scholarly journals A new experiment for gravitational wave detection

2021 ◽  
pp. 1-7
Author(s):  
Basem Ghayour ◽  
Jafar Khodagholizadeh ◽  
Christian Corda ◽  
Ming-Lei Tong ◽  
Ali Ghayour
Keyword(s):  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
The Other ◽  
New Method ◽  
Sound Waves ◽  
Wave Detection ◽  
Different Types ◽  
Local Observer ◽  
Pass Through

A new experiment for gravitational waves (GWs) detection is proposed. It is shown that the effect of GWs on sound waves (SWs) in a fluid is that GWs vary the pressure of the fluid as they pass through it. This variation can be found by analysing the gauge of the local observer. It is shown that one can, in principle, detect GWs through the proposed new experiment. The variation of the pressure of the fluid, which represents detected signals, is indeed much higher than the corresponding values of GW amplitudes. The examples of rotating neutron stars (NSs) and relic GWs are discussed. Remarkably, a comparison of the proposed new method with a previous paper of Singh et al. (New J. Phys. 19, 073023 (2017). doi: 10.1088/1367-2630/aa78cb ) on a similar approach shows a possible improvement of the sensitivity concerning the potential detection of GWs. It must be emphasized that this proposed procedure may be difficult in practical experiments because of the presence of different types of noise. For this reason, a section of the paper is dedicated to the discussion of such noise. On the other hand, this paper must be considered as pioneering the new proposed approach. Thus, we hope that in future more precise studies of the noise that concerns the proposed new experiment will be done.

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