scholarly journals Continuous Gravitational Waves from Neutron Stars: Current Status and Prospects

Universe ◽  
2019 ◽  
Vol 5 (11) ◽  
pp. 217 ◽  
Author(s):  
Magdalena Sieniawska ◽  
Michał Bejger

Gravitational waves astronomy allows us to study objects and events invisible in electromagnetic waves. It is crucial to validate the theories and models of the most mysterious and extreme matter in the Universe: the neutron stars. In addition to inspirals and mergers of neutrons stars, there are currently a few proposed mechanisms that can trigger radiation of long-lasting gravitational radiation from neutron stars, such as e.g., elastically and/or magnetically driven deformations: mountains on the stellar surface supported by the elastic strain or magnetic field, free precession, or unstable oscillation modes (e.g., the r-modes). The astrophysical motivation for continuous gravitational waves searches, current LIGO and Virgo strategies of data analysis and prospects are reviewed in this work.

Author(s):  
Paul D. Lasky

AbstractNeutron stars are excellent emitters of gravitational waves. Squeezing matter beyond nuclear densities invites exotic physical processes, many of which violently transfer large amounts of mass at relativistic velocities, disrupting spacetime and generating copious quantities of gravitational radiation. I review mechanisms for generating gravitational waves with neutron stars. This includes gravitational waves from radio and millisecond pulsars, magnetars, accreting systems, and newly born neutron stars, with mechanisms including magnetic and thermoelastic deformations, various stellar oscillation modes, and core superfluid turbulence. I also focus on what physics can be learnt from a gravitational wave detection, and where additional research is required to fully understand the dominant physical processes at play.


2021 ◽  
pp. 36-52
Author(s):  
Gianfranco Bertone

I present the momentous discovery of gravitational waves, announced in 2016, starting from a confused Einstein who in 1936 tries to convince the scientific community that gravitational waves cannot exist (!), and then illustrating the extraordinary insights and breakthroughs that led 2017 Nobel Prize winners B. Barish, K. Thorne and R. Weiss to open an entirely new window on the Universe. This achievement has marked the beginning of a new era in science, and upcoming experiments have the potential to truly revolutionize our understanding of the Universe. Accounts of the perception of extra-terrestrial reality with senses beyond sight, such as those offered by astronauts who have been on the Moon, are exceedingly rare. That is hardly unsurprising: touch and taste require direct contact, while hearing and smell operate only over short distances, and are in any case confined to the Earth’s thin shell of atmosphere. Sight, on the other hand, allows us to collect the electromagnetic waves emitted by extraordinarily remote celestial objects.


2005 ◽  
Vol 20 (31) ◽  
pp. 2335-2349 ◽  
Author(s):  
OMAR BENHAR

The EOS of strongly interacting matter at densities ten to fifteen orders of magnitude larger than the typical density of terrestrial macroscopic objects determines a number of neutron star properties, including the pattern of gravitational waves emitted following the excitation of nonradial oscillation modes. This paper reviews some of the approaches employed to model neutron star matter, as well as the prospects for obtaining new insights from the experimental study of gravitational waves emitted by neutron stars.


2015 ◽  
Vol 30 (28n29) ◽  
pp. 1545019
Author(s):  
David Blair ◽  
Li Ju ◽  
Chunnong Zhao ◽  
Linqing Wen ◽  
Qi Chu ◽  
...  

This paper begins by reviewing the development of gravitational wave astronomy from the first predictions of gravitational waves to development of technologies across the entire gravitational wave spectrum, and then focuses on the current status of ground based gravitational wave detectors. With substantial improvements already demonstrated in early commissioning it is emphasised that Advanced detectors are on track for first detection of gravitational waves. The importance of a worldwide array of detectors is emphasised, and recent results are shown that demonstrate the continued advantage of a southern hemisphere detector. Finally it is shown that a north–south pair of 8 km arm length detectors would give rise to a dramatic improvement in event rate, enabling a pair of detectors to encompass a 64-times larger volume of the universe, to conduct a census on all stellar mass black hole mergers to [Formula: see text] and to observe neutron star mergers to a distance of [Formula: see text][Formula: see text]800 Mpc.


2002 ◽  
Vol 185 ◽  
pp. 612-615
Author(s):  
Johannes Ruoff

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.


2000 ◽  
Vol 177 ◽  
pp. 727-732
Author(s):  
Bernard F. Schutz

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.


1996 ◽  
Vol 165 ◽  
pp. 153-183
Author(s):  
Kip S. Thorne

According to general relativity theory, compact concentrations of energy (e.g., neutron stars and black holes) should warp spacetime strongly, and whenever such an energy concentration changes shape, it should create a dynamically changing spacetime warpage that propagates out through the Universe at the speed of light. This propagating warpage is called gravitational radiation — a name that arises from general relativity's description of gravity as a consequence of spacetime warpage.


Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 137
Author(s):  
Andrzej Królak ◽  
Paritosh Verma

In this paper we present the most recent observations of gravitational waves (GWs) by LIGO and Virgo detectors. We also discuss contributions of the recent Nobel prize winner, Sir Roger Penrose to understanding gravitational radiation and black holes (BHs). We make a short introduction to GW phenomenon in general relativity (GR) and we present main sources of detectable GW signals. We describe the laser interferometric detectors that made the first observations of GWs. We briefly discuss the first direct detection of GW signal that originated from a merger of two BHs and the first detection of GW signal form merger of two neutron stars (NSs). Finally we present in more detail the observations of GW signals made during the first half of the most recent observing run of the LIGO and Virgo projects. Finally we present prospects for future GW observations.


Author(s):  
Seiji Kawamura ◽  
Masaki Ando ◽  
Naoki Seto ◽  
Shuichi Sato ◽  
Mitsuru Musha ◽  
...  

Abstract Deci-hertz Interferometer Gravitational Wave Observatory (DECIGO) is the future Japanese space mission with a frequency band of 0.1 Hz to 10 Hz. DECIGO aims at the detection of primordial gravitational waves, which could be produced during the inflationary period right after the birth of the universe. There are many other scientific objectives of DECIGO, including the direct measurement of the acceleration of the expansion of the universe, and reliable and accurate predictions of the timing and locations of neutron star/black hole binary coalescences. DECIGO consists of four clusters of observatories placed in the heliocentric orbit. Each cluster consists of three spacecraft, which form three Fabry-Perot Michelson interferometers with an arm length of 1,000 km. Three clusters of DECIGO will be placed far from each other, and the fourth cluster will be placed in the same position as one of the three clusters to obtain the correlation signals for the detection of the primordial gravitational waves. We plan to launch B-DECIGO, which is a scientific pathfinder of DECIGO, before DECIGO in the 2030s to demonstrate the technologies required for DECIGO, as well as to obtain fruitful scientific results to further expand the multi-messenger astronomy.


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