The Electromagnetic Counterpart of the Gravitational Wave Source GW170817 Invited Talk
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Measurement of the Speed of Gravity
Measurement of the Speed of Gravity Yin Zhu Agriculture Department of Hubei Province, Wuhan, China Abstract From the Liénard-Wiechert potential in both the gravitational field and the electromagnetic field, it is shown that the speed of propagation of the gravitational field (waves) can be tested by comparing the measured speed of gravitational force with the measured speed of Coulomb force. PACS: 04.20.Cv; 04.30.Nk; 04.80.Cc Fomalont and Kopeikin [1] in 2002 claimed that to 20% accuracy they confirmed that the speed of gravity is equal to the speed of light in vacuum. Their work was immediately contradicted by Will [2] and other several physicists. [3-7] Fomalont and Kopeikin [1] accepted that their measurement is not sufficiently accurate to detect terms of order , which can experimentally distinguish Kopeikin interpretation from Will interpretation. Fomalont et al [8] reported their measurements in 2009 and claimed that these measurements are more accurate than the 2002 VLBA experiment [1], but did not point out whether the terms of order have been detected. Within the post-Newtonian framework, several metric theories have studied the radiation and propagation of gravitational waves. [9] For example, in the Rosen bi-metric theory, [10] the difference between the speed of gravity and the speed of light could be tested by comparing the arrival times of a gravitational wave and an electromagnetic wave from the same event: a supernova. Hulse and Taylor [11] showed the indirect evidence for gravitational radiation. However, the gravitational waves themselves have not yet been detected directly. [12] In electrodynamics the speed of electromagnetic waves appears in Maxwell equations as c = √휇0휀0, no such constant appears in any theory of gravity. -
A Brief History of Gravitational Waves
universe Review A Brief History of Gravitational Waves Jorge L. Cervantes-Cota 1, Salvador Galindo-Uribarri 1 and George F. Smoot 2,3,4,* 1 Department of Physics, National Institute for Nuclear Research, Km 36.5 Carretera Mexico-Toluca, Ocoyoacac, C.P. 52750 Mexico, Mexico; [email protected] (J.L.C.-C.); [email protected] (S.G.-U.) 2 Helmut and Ana Pao Sohmen Professor at Large, Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077 Hong Kong, China 3 Université Sorbonne Paris Cité, Laboratoire APC-PCCP, Université Paris Diderot, 10 rue Alice Domon et Leonie Duquet, 75205 Paris Cedex 13, France 4 Department of Physics and LBNL, University of California; MS Bldg 50-5505 LBNL, 1 Cyclotron Road Berkeley, 94720 CA, USA * Correspondence: [email protected]; Tel.:+1-510-486-5505 Academic Editors: Lorenzo Iorio and Elias C. Vagenas Received: 21 July 2016; Accepted: 2 September 2016; Published: 13 September 2016 Abstract: This review describes the discovery of gravitational waves. We recount the journey of predicting and finding those waves, since its beginning in the early twentieth century, their prediction by Einstein in 1916, theoretical and experimental blunders, efforts towards their detection, and finally the subsequent successful discovery. Keywords: gravitational waves; General Relativity; LIGO; Einstein; strong-field gravity; binary black holes 1. Introduction Einstein’s General Theory of Relativity, published in November 1915, led to the prediction of the existence of gravitational waves that would be so faint and their interaction with matter so weak that Einstein himself wondered if they could ever be discovered. -
Gravitational Waves from Supernova Core Collapse Outline Max Planck Institute for Astrophysics, Garching, Germany
Gravitational Waves from Supernova Core Collapse Outline Max Planck Institute for Astrophysics, Garching, Germany Harald Dimmelmeier [email protected] Gravitational Waves from Supernova Core Collapse: What could the Signal tell us? Work done at the MPA in Garching Dimmelmeier, Font, M¨uller, Astron. Astrophys., 388, 917{935 (2002), astro-ph/0204288 Dimmelmeier, Font, M¨uller, Astron. Astrophys., 393, 523{542 (2002), astro-ph/0204289 Source Simulation Focus Session, Center for Gravitational Wave Physics, Penn State University, 2002 Gravitational Waves from Supernova Core Collapse Max Planck Institute for Astrophysics, Garching, Germany Motivation Physics of Core Collapse Supernovæ Physical model of core collapse supernova: Massive progenitor star (Mprogenitor 10 30M ) develops an iron core (Mcore 1:5M ). • ≈ − ≈ This approximate 4/3-polytrope becomes unstable and collapses (Tcollapse 100 ms). • ≈ During collapse, neutrinos are practically trapped and core contracts adiabatically. • At supernuclear density, hot proto-neutron star forms (EoS of matter stiffens bounce). • ) During bounce, gravitational waves are emitted; they are unimportant for collapse dynamics. • Hydrodynamic shock propagates from sonic sphere outward, but stalls at Rstall 300 km. • ≈ Collapse energy is released by emission of neutrinos (Tν 1 s). • ≈ Proto-neutron subsequently cools, possibly accretes matter, and shrinks to final neutron star. • Neutrinos deposit energy behind stalled shock and revive it (delayed explosion mechanism). • Shock wave propagates through -
Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: Gw170817 and Grb 170817A
GRAVITATIONAL WAVES AND GAMMA-RAYS FROM A BINARY NEUTRON STAR MERGER: GW170817 AND GRB 170817A The gravitational-wave signal GW170817 was detected on August 17, 2017 by the Advanced LIGO and Virgo observatories. This is the first signal thought to be due to the merger of two neutron stars. Only 1.7 seconds after the gravitational-wave signal was detected, the Fermi Gamma-ray Burst Monitor (GBM) and the Anticoincidence Shield for the SPectrometer for the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL SPI-ACS) detected a short gamma-ray burst GRB 170817A. For decades astronomers suspected that short gamma-ray bursts were produced by the merger of two neutron stars or a neutron star and a black hole. The combination of GW170817 and GRB 170817A provides the first direct evidence that colliding neutron stars can indeed produce short gamma-ray bursts. INTRODUCTION FIGURES FROM THE PUBLICATION Gamma-Ray Bursts (GRBs) are some of the most energetic events For more information on the meaning of these figures, see the full publication here. observed in Nature. They typically release as much energy in just a few seconds as our Sun will throughout its 10 billion-year life. They occur approximately once a day and come from random points on the sky. These GRBs can last anywhere from fractions of seconds to thousands of seconds. However, we usually divide them in two groups based roughly on their duration, with the division being at the 2 second mark (although more sophisticated features are also taken into account in the classification). Long GRBs (>2 seconds) are caused by the core-collapse of rapidly rotating massive stars. -
R-Process Nucleosynthesis in Neutron Star Mergers and GW170817
r-Process nucleosynthesis in neutron star mergers and GW170817 Jonas Lippuner July 18, 2018 FRIB and the GW170817 Kilonova FRIB/NSCL/MSU, East Lansing MI Operated by Los Alamos National Security, LLC for the U.S. Department of Energy’s NNSA Los Alamos National Laboratory UNCLASSIFIED LA-UR-18-21867 Outline 1. r-Process nucleosynthesis overview 2. r-Process in neutron star mergers 3. Observational signature and first detection Los Alamos National Laboratory UNCLASSIFIED 3/19/2018 | 2 Solar system abundances Los Alamos National Laboratory UNCLASSIFIED 3/19/2018 | 3 Solar system abundances Los Alamos National Laboratory UNCLASSIFIED 3/19/2018 | 3 The s-process slow neutron capture 90Zr 91Zr 92Zr τ ≪ τ ∼ 2 − 5 89 β− n 10 10 yr Y 84Sr 86Sr 87Sr 88Sr 85Rb 87Rb 78Kr 80Kr 82Kr 83Kr 84Kr 86Kr 79Br 81Br 74Se 76Se 77Se 78Se 80Se 82Se 75As 70Ge 72Ge 73Ge 74Ge 76Ge 69Ga 71Ga 66Zn 67Zn 68Zn 70Zn 65Cu closed neutron shell Los Alamos National Laboratory UNCLASSIFIED 3/19/2018 | 4 The s-process slow neutron capture 90Zr 91Zr 92Zr τ ≪ τ ∼ 2 − 5 89 β− n 10 10 yr Y 84Sr 86Sr 87Sr 88Sr 85Rb 87Rb 78Kr 80Kr 82Kr 83Kr 84Kr 86Kr 79Br 81Br 74Se 76Se 77Se 78Se 80Se 82Se 75As 70Ge 72Ge 73Ge 74Ge 76Ge 69Ga 71Ga 66Zn 67Zn 68Zn 70Zn 65Cu closed neutron shell Los Alamos National Laboratory UNCLASSIFIED 3/19/2018 | 4 The r-process rapid neutron capture 90Zr 91Zr 92Zr τ ≪ τ ∼ n β− 10 ms – 10 s 89Y 84Sr 86Sr 87Sr 88Sr 85Rb 87Rb 78Kr 80Kr 82Kr 83Kr 84Kr 86Kr 79Br 81Br 74Se 76Se 77Se 78Se 80Se 82Se 75As 70Ge 72Ge 73Ge 74Ge 76Ge 69Ga 71Ga 66Zn 67Zn 68Zn 70Zn 65Cu neutron drip -
A Brief History of Gravitational Waves
Review A Brief History of Gravitational Waves Jorge L. Cervantes-Cota 1, Salvador Galindo-Uribarri 1 and George F. Smoot 2,3,4,* 1 Department of Physics, National Institute for Nuclear Research, Km 36.5 Carretera Mexico-Toluca, Ocoyoacac, Mexico State C.P.52750, Mexico; [email protected] (J.L.C.-C.); [email protected] (S.G.-U.) 2 Helmut and Ana Pao Sohmen Professor at Large, Institute for Advanced Study, Hong Kong University of Science and Technology, Clear Water Bay, 999077 Kowloon, Hong Kong, China. 3 Université Sorbonne Paris Cité, Laboratoire APC-PCCP, Université Paris Diderot, 10 rue Alice Domon et Leonie Duquet 75205 Paris Cedex 13, France. 4 Department of Physics and LBNL, University of California; MS Bldg 50-5505 LBNL, 1 Cyclotron Road Berkeley, CA 94720, USA. * Correspondence: [email protected]; Tel.:+1-510-486-5505 Abstract: This review describes the discovery of gravitational waves. We recount the journey of predicting and finding those waves, since its beginning in the early twentieth century, their prediction by Einstein in 1916, theoretical and experimental blunders, efforts towards their detection, and finally the subsequent successful discovery. Keywords: gravitational waves; General Relativity; LIGO; Einstein; strong-field gravity; binary black holes 1. Introduction Einstein’s General Theory of Relativity, published in November 1915, led to the prediction of the existence of gravitational waves that would be so faint and their interaction with matter so weak that Einstein himself wondered if they could ever be discovered. Even if they were detectable, Einstein also wondered if they would ever be useful enough for use in science. -
Gravitational Waves and Core-Collapse Supernovae
Gravitational waves and core-collapse supernovae G.S. Bisnovatyi-Kogan(1,2), S.G. Moiseenko(1) (1)Space Research Institute, Profsoyznaya str/ 84/32, Moscow 117997, Russia (2)National Research Nuclear University MEPhI, Kashirskoe shosse 32,115409 Moscow, Russia Abstract. A mechanism of formation of gravitational waves in 1. Introduction the Universe is considered for a nonspherical collapse of matter. Nonspherical collapse results are presented for a uniform spher- On February 11, 2016, LIGO (Laser Interferometric Gravita- oid of dust and a finite-entropy spheroid. Numerical simulation tional-wave Observatory) in the USA with great fanfare results on core-collapse supernova explosions are presented for announced the registration of a gravitational wave (GW) the neutrino and magneto-rotational models. These results are signal on September 14, 2015 [1]. A fantastic coincidence is used to estimate the dimensionless amplitude of the gravita- that the discovery was made exactly 100 years after the tional wave with a frequency m 1300 Hz, radiated during the prediction of GWs by Albert Einstein on the basis of his collapse of the rotating core of a pre-supernova with a mass of theory of General Relativity (GR) (the theory of space and 1:2 M (calculated by the authors in 2D). This estimate agrees time). A detailed discussion of the results of this experiment well with many other calculations (presented in this paper) that and related problems can be found in [2±6]. have been done in 2D and 3D settings and which rely on more Gravitational waves can be emitted by binary stars due to exact and sophisticated calculations of the gravitational wave their relative motion or by collapsing nonspherical bodies. -
Gravitational Wave Echoes from Black Hole Area Quantization
Prepared for submission to JCAP Gravitational wave echoes from black hole area quantization Vitor Cardoso,a;b Valentino F. Foit,c Matthew Klebanc aCentro de Astrofísica e Gravitação - CENTRA, Departamento de Física Instituto Superior Técnico - IST, Universidade de Lisboa, Lisboa, Portugal bTheoretical Physics Department, CERN 1 Esplanade des Particules, Geneva 23, CH-1211, Switzerland cCenter for Cosmology and Particle Physics New York University, New York, USA E-mail: [email protected], [email protected], [email protected] Abstract. Gravitational-wave astronomy has the potential to substantially advance our knowledge of the cosmos, from the most powerful astrophysical engines to the initial stages of our universe. Gravitational waves also carry information about the nature of black holes. Here we investigate the potential of gravitational-wave detectors to test a proposal by Beken- stein and Mukhanov that the area of black hole horizons is quantized in units of the Planck area. Our results indicate that this quantization could have a potentially observable effect on the classical gravitational wave signals received by detectors. In particular, we find distorted gravitational-wave “echoes” in the post-merger waveform describing the inspiral and merger of two black holes. These echoes have a specific frequency content that is characteristic of black hole horizon area quantization. arXiv:1902.10164v1 [hep-th] 26 Feb 2019 Contents 1 Introduction1 1.1 Quantization of black hole area1 1.2 Imprints on classical observables2 1.2.1 Gravitational-wave -
Einstein's Discovery of Gravitational Waves 1916-1918
1 Einstein’s Discovery of Gravitational Waves 1916-1918 Galina Weinstein 12/2/16 In his 1916 ground-breaking general relativity paper Einstein had imposed a restrictive coordinate condition; his field equations were valid for a system –g = 1. Later, Einstein published a paper on gravitational waves. The solution presented in this paper did not satisfy the above restrictive condition. In his gravitational waves paper, Einstein concluded that gravitational fields propagate at the speed of light. The solution is the Minkowski flat metric plus a small disturbance propagating in a flat space-time. Einstein calculated the small deviation from Minkowski metric in a manner analogous to that of retarded potentials in electrodynamics. However, in obtaining the above derivation, Einstein made a mathematical error. This error caused him to obtain three different types of waves compatible with his approximate field equations: longitudinal waves, transverse waves and a new type of wave. Einstein added an Addendum in which he suggested that in a system –g = 1 only waves of the third type occur and these waves transport energy. He became obsessed with his system –g = 1. Einstein’s colleagues demonstrated to him that in the coordinate system –g = 1 the gravitational wave of a mass point carry no energy, but Einstein tried to persuade them that he had actually not made a mistake in his gravitational waves paper. Einstein, however, eventually accepted his colleagues results and dropped the restrictive condition –g = 1. This finally led him to discover plane transverse gravitational waves. Already in 1913, at the eighty-fifth congress of the German Natural Scientists and Physicists in Vienna, Einstein started to think about gravitational waves when he worked on the Entwurf theory. -
Gravitational-Wave Asteroseismology with Fundamental Modes from Compact Binary Inspirals ✉ ✉ ✉ Geraint Pratten 1,2 , Patricia Schmidt 1 & Tanja Hinderer3,4
ARTICLE https://doi.org/10.1038/s41467-020-15984-5 OPEN Gravitational-wave asteroseismology with fundamental modes from compact binary inspirals ✉ ✉ ✉ Geraint Pratten 1,2 , Patricia Schmidt 1 & Tanja Hinderer3,4 Gravitational waves (GWs) from binary neutron stars encode unique information about ultra- dense matter through characterisic signatures associated with a variety of phenomena including tidal effects during the inspiral. The main tidal signature depends predominantly on Λ 1234567890():,; the equation of state (EoS)-related tidal deformability parameter , but at late times is also characterised by the frequency of the star’s fundamental oscillation mode (f-mode). In General Relativity and for nuclear matter, Λ and the f-modes are related by universal relations which may not hold for alternative theories of gravity or exotic matter. Independently measuring Λ and the f-mode frequency enables tests of gravity and the nature of compact binaries. Here we present directly measured constraints on the f-mode frequencies of the companions of GW170817. We also show that future GW detector networks will measure f- mode frequencies to within tens of Hz, enabling precision GW asteroseismology with binary inspiral signals alone. 1 School of Physics and Astronomy and Institute for Gravitational Wave Astronomy, University of Birmingham, Edgbaston, Birmingham B15 9TT, United Kingdom. 2 Universitat de les Illes Balears, Crta. Valldemossa km 7.5, E-07122 Palma, Spain. 3 GRAPPA, Anton Pannekoek Institute for Astronomy and Institute of High-Energy Physics, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands. 4 Delta Institute for Theoretical ✉ Physics, Science Park 904, 1090 GL Amsterdam, The Netherlands. -
Dense Nuclear Matter and Gravitational Waves Alex Nielsen Quo Vadis QCD Stavanger, Norway Wed 2Nd October 2019 Image Credit: Norbert Wex
Dense nuclear matter and gravitational waves Alex Nielsen Quo Vadis QCD Stavanger, Norway Wed 2nd October 2019 Image Credit: Norbert Wex Neutron star radius is not directly measured in pulsars, X-ray binaries or gravitational waves, but is dependent on the matter Equation of State LIGO-Virgo result for gravitational wave event GW170817 Fig 3, LVC, PRL121, (2018) 161101 Assumptions in fitting tidal parameters ● Event is an astrophysical gravitational wave event ● Event is two neutron stars ● Event occurs exactly at the location of optical counterpart ● Both spins are low, consistent with observed galactic binaries ● Both neutron stars have the same equation of state ● GW detector noise is Gaussian, de-glitching of L1 is successful ● PhenomPNRT waveform model is accurate in inspiral phase Gravitational wave detectors (this one in Italy) Image Credit:The Virgo Collaboration Notable gravitational wave events (so far) • GW150914 Binary Black Hole (BBH) • GW170817 Binary Neutron Star (BNS) Image Credit: NASA/Dana Berry Multi-messenger astronomy, 3,677 authors... GW and EM observations of GW170817 (no neutrinos or cosmic rays seen) Fig 2, ApJL848, (2017) L12 “But, as critics have pointed out correctly, the LIGO alert for this event came 40 minutes after NASA’s gamma-ray alert. For this reason, the event cannot be used as an independent GW170817 timeline confirmation of LIGO’s detection capacity.” –Hossenfelder, 4 Sep 2019 ● 12 41:04 GstLAL automatic alert of single trigger in H1 ● 12 41:06 onboard GRB trigger on GBM ∶ ● +~15 mins Rapid Response -
LIGO Educator's Guide
Direct Observation of Gravitational Waves Educator’s Guide Direct Observation of Gravitational Waves Educator’s Guide http://www.ligo.org Content 3 Introduction 4 Background 4 Gravitational Waves as Signals from the Universe 5 Gravity from Newton to Einstein 8 Gravitational Waves 10 The Direct Observation of Gravitational Waves by LIGO 13 Black Holes 14 Activities 14 • Activity 1 - Coalescing Black Holes 16 • Activity 2 - Warping of Spacetime 18 Next Generation Science Standards 19 Appendix A - Glossary 20 Appendix B - Resources 21 Appendix C - Purchasing Information LIGO Educator’s Guide — This guide was written by Kevin McLin, Carolyn Peruta and Lynn Cominsky. Layout and Design by Aurore Simonnet. SSU Education and Public Outreach Group, Sonoma State University, Rohnert Park, CA – http://epo.sonoma.edu We gratefully acknowledge comments and review by Beverly Berger, Joey Key, William Katzman and Dale Ingram. This work was supported by a supplement to NSF PHY-1404215. Updates may be downloaded from https://dcc.ligo.org/LIGO-P1600015 Introduction On September 14, 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) received the first confirmed gravitational wave signals. Now known as GW150914 (for the date on which the signals were received in 2015, 9th month, day 14), the event represents the coalescence of two black holes that were previously in mutual orbit. LIGO’s exciting discovery provides direct evidence of what is arguably the last major unconfirmed prediction of Einstein’s General Theory of Relativity. This Educator’s Guide provides a brief introduction to LIGO and to gravitational waves, along with two simple demonstration activities that you can do in your classroom to engage your students in understanding LIGO’s discovery.