scholarly journals Recent Observations of Gravitational Waves by LIGO and Virgo Detectors

Universe ◽  
2021 ◽  
Vol 7 (5) ◽  
pp. 137
Author(s):  
Andrzej Królak ◽  
Paritosh Verma
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Neutron Stars ◽  
Gravitational Waves ◽  
Gravitational Radiation ◽  
Direct Detection ◽  
Nobel Prize Winner ◽  
Short Introduction ◽  
Interferometric Detectors ◽  
Laser Interferometric

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.

Beyond the Schwarzschild Metric

2018 ◽  
Author(s):  
David M. Wittman
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Waves ◽  
Test Particle ◽  
Direct Detection ◽  
Relativistic Effects ◽  
Big Bang ◽  
Clusters Of Galaxies ◽  
General Relativistic ◽  
The Universe

General relativity explains much more than the spacetime around static spherical masses.We briefly assess general relativity in the larger context of physical theories, then explore various general relativistic effects that have no Newtonian analog. First, source massmotion gives rise to gravitomagnetic effects on test particles.These effects also depend on the velocity of the test particle, which has substantial implications for orbits around black holes to be further explored in Chapter 20. Second, any changes in the sourcemass ripple outward as gravitational waves, and we tell the century‐long story from the prediction of gravitational waves to their first direct detection in 2015. Third, the deflection of light by galaxies and clusters of galaxies allows us to map the amount and distribution of mass in the universe in astonishing detail. Finally, general relativity enables modeling the universe as a whole, and we explore the resulting Big Bang cosmology.

Detecting Blackholes through Gravitational Waves

2014 ◽  
Author(s):  
Charles D. Bailyn
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Electromagnetic Radiation ◽  
Gravitational Waves ◽  
Gravitational Radiation ◽  
Stellar Mass ◽  
Supermassive Black Holes ◽  
Current Technology

This chapter looks at the detection of black holes through gravitational waves. While further improvements can be expected in the ability to detect and measure electromagnetic radiation, it is possible that the next great advances in observational astrophysics will come from the detection of other kinds of information altogether. Currently, there is a great excitement about the possibility of directly detecting an entirely new “celestial messenger,” namely, gravitational radiation. The existence of gravitational waves is a prediction of general relativity, and current technology is very close to being able to detect them directly. The strongest sources of gravitational radiation are expected to be merging black holes. Since such mergers are expected to occur, both between stellar-mass and supermassive black holes, the detection of gravitational radiation would provide a new way not only to explore gravitational physics but also to look for and to study celestial black holes.

The Direct Detection of Gravitational Waves

2018 ◽  
pp. 106-109
Author(s):  
Alvaro De Rújula
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Gravitational Waves ◽  
Direct Detection ◽  
Space Time ◽  
New Era ◽  
The Third ◽  
Perfect Storm

Gravitational waves emitted by black hole mergers. The first LIGO event: GW150917, the coalescence of two black holes of twenty nine and thirty six solar masses into one of “only” sixty two. The remaining three solar masses were emitted as energy in gravitational waves, a gigantic and perfect storm in the fabric of space-time. This is the dawn of a new era: The opening of the third “window” through which to look at the sky. Yet another triumph of general relativity. How much progress astrophysics has made since my time as a student.

scholarly journals Gravitational Waves from Compact Bodies

1996 ◽  
Vol 165 ◽  
pp. 153-183
Author(s):  
Kip S. Thorne
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Neutron Stars ◽  
Gravitational Radiation ◽  
Relativity Theory ◽  
Energy Concentration ◽  
Speed Of Light ◽  
General Relativity Theory ◽  
Concentration Changes ◽  
The Universe

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.

scholarly journals Persamaan Gelombang Gravitasi untuk Teori Proca yang Digeneralisasi

2020 ◽  
Vol 5 ◽  
Author(s):  
Marliana Marliana ◽  
Agustina Widiyani ◽  
Azwar Sutiono ◽  
Agus Suroso ◽  
Freddy P. Zen
Keyword(s):  
Black Holes ◽  
Vector Field ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
General Equation ◽  
Direct Detection ◽  
Gravity Theory ◽  
Binary Black Holes ◽  
Massive Vector

<p class="AbstractEnglish"><strong>Abstract:</strong> The direct detection of gravitational waves from binary black holes and neutron stars have been taking a new oportunities to test teori of gravity.The gravitational wave is affected by the modification of a gravity theory during propagation at cosmological distances. By comparing general equation of gravtiational wave and modification of gravity theory, is obtained equation of gravitational wave for the generalized Proca theories. As a result, we find equation of gravitational wave for the generalized Proca theory. We conclude that the massive vector field affected propagation of gravitational wave.  we can use the result to test the generalized Proca theory.    </p><p class="AbstrakIndonesia"><strong>Abstrak:</strong> Dengan terdeteksinya gelombang gravitasi secara langsung dari biner lubang hitam dan bintang neutron menjadi kesempatan untuk dapat menguji teori gravitasi yang sedang dikembangkan.Gelombang gravitasi secara umum dipengaruhi oleh modifikasi teori gravitasi selama penjalarannya pada jarak kosmologi. Dengan membandingkan persamaan gelombang gravitasi dengan teori modifikasi yang dikembangkan, diperoleh persamaan umum gelombang gravitasi dari teori gravitasi yang dikembangkan. Pada artikel ini diperoleh persamaan gelombang gravitasi untuk teori Proca yang digeneralisasi. Dapat disimpulkan bahwa fungsi yang mengandung vektor medan masif dapat mempengaruhi gelombang gravitasi. Persamaan ini dapat digunakan untuk menguji teori Proca yang digeneralisasi.</p>

scholarly journals Pulsar Identification of Background Spectra of LIGO Data

2018 ◽  
Vol 1 (2) ◽  
Keyword(s):  
Black Holes ◽  
Exact Solution ◽  
General Relativity ◽  
Time Delay ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Compact Objects ◽  
Gravitational Redshift ◽  
Wave Spectra

By choosing the metric (called physical metric) in general relativity as the exact solution to the Einstein equation that fits the time delay data, one can determine the size and gravitational redshift on the surface of compact objects (neutron stars and black holes). The author shows that the physical metric is invariant by rotation. As a result, the frequencies of gravitational waves from pulsars are represented as n * f / for pulsar frequency f and harmonics n. Based on this result, the author has identified potential pulsar candidates with gravitational wave spectra. This result will be critical in the study of gravitational redshift of compact objects.

Gravity

2021 ◽  
Author(s):  
James B. Hartle
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Gravitational Waves ◽  
Undergraduate Curriculum ◽  
Physics First ◽  
Cambridge University ◽  
Introductory Course ◽  
Modern Physics ◽  
The Subject ◽  
Curriculum Making

Einstein's theory of general relativity is a cornerstone of modern physics. It also touches upon a wealth of topics that students find fascinating – black holes, warped spacetime, gravitational waves, and cosmology. Now reissued by Cambridge University Press, this ground-breaking text helped to bring general relativity into the undergraduate curriculum, making it accessible to virtually all physics majors. One of the pioneers of the 'physics-first' approach to the subject, renowned relativist James B. Hartle, recognized that there is typically not enough time in a short introductory course for the traditional, mathematics-first, approach. In this text, he provides a fluent and accessible physics-first introduction to general relativity that begins with the essential physical applications and uses a minimum of new mathematics. This market-leading text is ideal for a one-semester course for undergraduates, with only introductory mechanics as a prerequisite.

A Tale of Two Infinities

2021 ◽  
Author(s):  
Gianfranco Bertone
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Gravitational Waves ◽  
Direct Detection ◽  
Traditional Approach ◽  
Fundamental Physics ◽  
Modern Cosmology ◽  
Nobel Prize In Physics ◽  
The Universe ◽  
Modern Astronomy

The spectacular advances of modern astronomy have opened our horizon on an unexpected cosmos: a dark, mysterious Universe, populated by enigmatic entities we know very little about, like black holes, or nothing at all, like dark matter and dark energy. In this book, I discuss how the rise of a new discipline dubbed multimessenger astronomy is bringing about a revolution in our understanding of the cosmos, by combining the traditional approach based on the observation of light from celestial objects, with a new one based on other ‘messengers’—such as gravitational waves, neutrinos, and cosmic rays—that carry information from otherwise inaccessible corners of the Universe. Much has been written about the extraordinary potential of this new discipline, since the 2017 Nobel Prize in physics was awarded for the direct detection of gravitational waves. But here I will take a different angle and explore how gravitational waves and other messengers might help us break the stalemate that has been plaguing fundamental physics for four decades, and to consolidate the foundations of modern cosmology.

Frontiers of Quantum Black Holes

2020 ◽  
Vol 29 (11) ◽  
pp. 10-16
Author(s):  
Wontae KIM ◽  
Mu-In PARK
Keyword(s):  
Black Holes ◽  
General Relativity ◽  
Black Hole ◽  
Direct Detection ◽  
Occupation Number ◽  
Theory Of Relativity ◽  
General Theory Of Relativity ◽  
Quantum Radiation ◽  
Points Of View ◽  
Massless Quantum

A black hole is a theoretical prediction of Einstein’s general theory of relativity, differently from Newtonian gravity, which is a non-relativistic gravity. In recent few years, its direct detection via gravitational waves and other multi-messenger observations have made it possible to test the prediction and hence its associated general relativity. From purely theoretical points of view, general relativity cannot be a complete description due to its not being compatible with quantum mechanics, which is a successful description of microscopic objects. In this article, we introduce the conceptional development of quantum-gravity theories and give brief sketches of fundamental problems in quantum black holes. As an interesting model of quantum black holes, we consider a collapsing shell of matter to form a Hayward black hole and investigate semiclassically quantum radiation from the shell. By using the Israel’s formulation and the functional Schrödinger formulation for massless quantum radiation, we find that the Hawking temperature can be deduced from the occupation number of excited states when the shell approaches its own horizon.

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