Properties of the Binary Neutron Star Merger GW170817
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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. -
Towards Gravitational Wave Astronomy: Commissioning and Characterization of GEO 600
Journal of Physics: Conference Series Related content - Quantum measurements in gravitational- Towards gravitational wave astronomy: wave detectors F Ya Khalili Commissioning and characterization of GEO600 - Systematic survey for monitor signals to reduce fake burst events in a gravitational- wave detector To cite this article: S Hild et al 2006 J. Phys.: Conf. Ser. 32 66 Koji Ishidoshiro, Masaki Ando and Kimio Tsubono - Environmental Effects for Gravitational- wave Astrophysics Enrico Barausse, Vitor Cardoso and Paolo View the article online for updates and enhancements. Pani Recent citations - First joint search for gravitational-wave bursts in LIGO and GEO 600 data B Abbott et al - The status of GEO 600 H Grote (for the LIGO Scientific Collaboration) - Upper limits on gravitational wave emission from 78 radio pulsars W. G. Anderson et al This content was downloaded from IP address 194.95.159.70 on 30/01/2019 at 13:59 Institute of Physics Publishing Journal of Physics: Conference Series 32 (2006) 66–73 doi:10.1088/1742-6596/32/1/011 Sixth Edoardo Amaldi Conference on Gravitational Waves Towards gravitational wave astronomy: Commissioning and characterization of GEO 600 S. Hild1,H.Grote1,J.R.Smith1 and M. Hewitson1 for the GEO 600-team2 . 1 Max-Planck-Institut f¨ur Gravitationsphysik (Albert-Einstein-Institut) und Universit¨at Hannover, Callinstr. 38, D–30167 Hannover, Germany. 2 See GEO 600 status report paper for the author list of the GEO collaboration. E-mail: [email protected] Abstract. During the S4 LSC science run, the gravitational-wave detector GEO 600, the first large scale dual recycled interferometer, took 30 days of continuous√ data. -
GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2 – Supplemental Material
GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2 { Supplemental Material The LIGO Scientific Collaboration and the Virgo Collaboration I. NOISE PERFORMANCE OF THE sis used an initial calibration of the data and assumed DETECTORS a (conservative) one-sigma calibration uncertainty of 10% in amplitude and 10◦ in phase for both detec- Figure 1 shows a comparison of typical strain noise am- tors, a reduced-order quadrature model of the effective- plitude spectra during the first observing run and early precession waveform [15{18] (the most computationally in the second for both of the LIGO detectors [1]. For the expedient model), and a power spectral density cal- Hanford detector, shot-noise limited performance was im- culated using a parametrized model of the detector proved above about 500 Hz by increasing the laser power. noise [19, 20]. A stretch of 4 s of data, centered on There are new broad mechanical resonance features (e.g., the event, was analysed across a frequency range of 20{ at 150 Hz, 320 Hz and 350 Hz) due to increased beam 1024 Hz. We assumed uninformative prior probabili- pointing∼ jitter from the laser, as well as the coupling ties [11, 13]; technical restrictions of the reduced-order of the jitter to the detector's gravitational-wave channel quadrature required us to limit spin magnitudes to < 0:8 that is larger than in the Livingston detector. The in- and impose cuts on the masses (as measured in the de- det det crease in the noise between 40 Hz and 100 Hz is currently tector frame) such that m1;2 [5:5; 160] M , 2 M 2 under investigation. -
Determining the Hubble Constant with Black Hole Mergers in Active Galactic Nuclei
Determining the Hubble Constant with AGN-assisted Black Hole Mergers Y. Yang,1 V. Gayathri,1 S. M´arka,2 Z. M´arka,2 and I. Bartos1, ∗ 1Department of Physics, University of Florida, PO Box 118440, Gainesville, FL 32611, USA 2Department of Physics, Columbia University in the City of New York, New York, NY 10027, USA Gravitational waves from neutron star mergers have long been considered a promising way to mea- sure the Hubble constant, H0, which describes the local expansion rate of the Universe. While black hole mergers are more abundantly observed, their expected lack of electromagnetic emission and poor gravitational-wave localization makes them less suited for measuring H0. Black hole mergers within the disks of Active Galactic Nuclei (AGN) could be an exception. Accretion from the AGN disk may produce an electromagnetic signal, pointing observers to the host galaxy. Alternatively, the low number density of AGNs could help identify the host galaxy of 1 − 5% of mergers. Here we show that black hole mergers in AGN disks may be the most sensitive way to determine H0 with gravitational waves. If 1% of LIGO/Virgo's observations occur in AGN disks with identified host galaxies, we could measure H0 with 1% uncertainty within five years, likely beyond the sensitivity of neutrons star mergers. I. INTRODUCTION Multi-messenger gravitational-wave observations rep- resent a valuable, independent probe of the expansion of the Universe [1]. The Hubble constant, which de- scribes the rate of expansion, can measured using Type Ia supernovae, giving a local expansion rate of H0 = 74:03 ± 1:42 km s−1 Mpc−1 [2]. -
Observing Gravitational Waves from Spinning Neutron Stars LIGO-G060662-00-Z Reinhard Prix (Albert-Einstein-Institut)
Astrophysical Motivation Detecting Gravitational Waves from NS Observing Gravitational Waves from Spinning Neutron Stars LIGO-G060662-00-Z Reinhard Prix (Albert-Einstein-Institut) for the LIGO Scientific Collaboration Toulouse, 6 July 2006 R. Prix Gravitational Waves from Neutron Stars Astrophysical Motivation Detecting Gravitational Waves from NS Outline 1 Astrophysical Motivation Gravitational Waves from Neutron Stars? Emission Mechanisms (Mountains, Precession, Oscillations, Accretion) Gravitational Wave Astronomy of NS 2 Detecting Gravitational Waves from NS Status of LIGO (+GEO600) Data-analysis of continous waves Observational Results R. Prix Gravitational Waves from Neutron Stars Gravitational Waves from Neutron Stars? Astrophysical Motivation Emission Mechanisms Detecting Gravitational Waves from NS Gravitational Wave Astronomy of NS Orders of Magnitude Quadrupole formula (Einstein 1916). GW luminosity (: deviation from axisymmetry): 2 G MV 3 O(10−53) L ∼ 2 GW c5 R c5 R 2 V 6 O(1059) erg = 2 s s G R c 2 Schwarzschild radius Rs = 2GM/c Need compact objects in relativistic motion: Black Holes, Neutron Stars, White Dwarfs R. Prix Gravitational Waves from Neutron Stars Gravitational Waves from Neutron Stars? Astrophysical Motivation Emission Mechanisms Detecting Gravitational Waves from NS Gravitational Wave Astronomy of NS What is a neutron star? −1 Mass: M ∼ 1.4 M Rotation: ν . 700 s Radius: R ∼ 10 km Magnetic field: B ∼ 1012 − 1014 G =⇒ density: ρ¯ & ρnucl =⇒ Rs = 2GM ∼ . relativistic: R c2R 0 4 R. Prix Gravitational Waves from Neutron Stars Gravitational Waves from Neutron Stars? Astrophysical Motivation Emission Mechanisms Detecting Gravitational Waves from NS Gravitational Wave Astronomy of NS Gravitational Wave Strain h(t) + Plane gravitational wave hµν along z-direction: Lx −Ly Strain h(t) ≡ 2L : y Ly Lx x h(t) t R. -
Holographic Noise in Interferometers a New Experimental Probe of Planck Scale Unification
Holographic Noise in Interferometers A new experimental probe of Planck scale unification FCPA planning retreat, April 2010 1 Planck scale seconds The physics of this “minimum time” is unknown 1.616 ×10−35 m Black hole radius particle energy ~1016 TeV € Quantum particle energy size Particle confined to Planck volume makes its own black hole FCPA planning retreat, April 2010 2 Interferometers might probe Planck scale physics One interpretation of the Planck frequency/bandwidth limit predicts a new kind of uncertainty leading to a new detectable effect: "holographic noise” Different from gravitational waves or quantum field fluctuations Predicts Planck-amplitude noise spectrum with no parameters We are developing an experiment to test this hypothesis FCPA planning retreat, April 2010 3 Quantum limits on measuring event positions Spacelike-separated event intervals can be defined with clocks and light But transverse position measured with frequency-bounded waves is uncertain by the diffraction limit, Lλ0 This is much larger than the wavelength € Lλ0 L λ0 Add second€ dimension: small phase difference of events over Wigner (1957): quantum limits large transverse patch with one spacelike dimension FCPA planning€ retreat, April 2010 4 € Nonlocal comparison of event positions: phases of frequency-bounded wavepackets λ0 Wavepacket of phase: relative positions of null-field reflections off massive bodies € Δf = c /2πΔx Separation L € ΔxL = L(Δf / f0 ) = cL /2πf0 Uncertainty depends only on L, f0 € FCPA planning retreat, April 2010 5 € Physics Outcomes -
Advanced Virgo: Status of the Detector, Latest Results and Future Prospects
universe Review Advanced Virgo: Status of the Detector, Latest Results and Future Prospects Diego Bersanetti 1,* , Barbara Patricelli 2,3 , Ornella Juliana Piccinni 4 , Francesco Piergiovanni 5,6 , Francesco Salemi 7,8 and Valeria Sequino 9,10 1 INFN, Sezione di Genova, I-16146 Genova, Italy 2 European Gravitational Observatory (EGO), Cascina, I-56021 Pisa, Italy; [email protected] 3 INFN, Sezione di Pisa, I-56127 Pisa, Italy 4 INFN, Sezione di Roma, I-00185 Roma, Italy; [email protected] 5 Dipartimento di Scienze Pure e Applicate, Università di Urbino, I-61029 Urbino, Italy; [email protected] 6 INFN, Sezione di Firenze, I-50019 Sesto Fiorentino, Italy 7 Dipartimento di Fisica, Università di Trento, Povo, I-38123 Trento, Italy; [email protected] 8 INFN, TIFPA, Povo, I-38123 Trento, Italy 9 Dipartimento di Fisica “E. Pancini”, Università di Napoli “Federico II”, Complesso Universitario di Monte S. Angelo, I-80126 Napoli, Italy; [email protected] 10 INFN, Sezione di Napoli, Complesso Universitario di Monte S. Angelo, I-80126 Napoli, Italy * Correspondence: [email protected] Abstract: The Virgo detector, based at the EGO (European Gravitational Observatory) and located in Cascina (Pisa), played a significant role in the development of the gravitational-wave astronomy. From its first scientific run in 2007, the Virgo detector has constantly been upgraded over the years; since 2017, with the Advanced Virgo project, the detector reached a high sensitivity that allowed the detection of several classes of sources and to investigate new physics. This work reports the Citation: Bersanetti, D.; Patricelli, B.; main hardware upgrades of the detector and the main astrophysical results from the latest five years; Piccinni, O.J.; Piergiovanni, F.; future prospects for the Virgo detector are also presented. -
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. -
Probing the Nuclear Equation of State from the Existence of a 2.6 M Neutron Star: the GW190814 Puzzle
S S symmetry Article Probing the Nuclear Equation of State from the Existence of a ∼2.6 M Neutron Star: The GW190814 Puzzle Alkiviadis Kanakis-Pegios †,‡ , Polychronis S. Koliogiannis ∗,†,‡ and Charalampos C. Moustakidis †,‡ Department of Theoretical Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; [email protected] (A.K.P.); [email protected] (C.C.M.) * Correspondence: [email protected] † Current address: Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece. ‡ These authors contributed equally to this work. Abstract: On 14 August 2019, the LIGO/Virgo collaboration observed a compact object with mass +0.08 2.59 0.09 M , as a component of a system where the main companion was a black hole with mass ∼ − 23 M . A scientific debate initiated concerning the identification of the low mass component, as ∼ it falls into the neutron star–black hole mass gap. The understanding of the nature of GW190814 event will offer rich information concerning open issues, the speed of sound and the possible phase transition into other degrees of freedom. In the present work, we made an effort to probe the nuclear equation of state along with the GW190814 event. Firstly, we examine possible constraints on the nuclear equation of state inferred from the consideration that the low mass companion is a slow or rapidly rotating neutron star. In this case, the role of the upper bounds on the speed of sound is revealed, in connection with the dense nuclear matter properties. Secondly, we systematically study the tidal deformability of a possible high mass candidate existing as an individual star or as a component one in a binary neutron star system. -
Recent Observations of Gravitational Waves by LIGO and Virgo Detectors
universe Review Recent Observations of Gravitational Waves by LIGO and Virgo Detectors Andrzej Królak 1,2,* and Paritosh Verma 2 1 Institute of Mathematics, Polish Academy of Sciences, 00-656 Warsaw, Poland 2 National Centre for Nuclear Research, 05-400 Otwock, Poland; [email protected] * Correspondence: [email protected] Abstract: 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. Keywords: gravitational waves; black holes; neutron stars; laser interferometers 1. Introduction The first terrestrial direct detection of GWs on 14 September 2015, was a milestone Citation: Kro´lak, A.; Verma, P. discovery, and it opened up an entirely new window to explore the universe. The combined Recent Observations of Gravitational effort of various scientists and engineers worldwide working on the theoretical, experi- Waves by LIGO and Virgo Detectors. -
Stochastic Gravitational Wave Backgrounds
Stochastic Gravitational Wave Backgrounds Nelson Christensen1;2 z 1ARTEMIS, Universit´eC^oted'Azur, Observatoire C^oted'Azur, CNRS, 06304 Nice, France 2Physics and Astronomy, Carleton College, Northfield, MN 55057, USA Abstract. A stochastic background of gravitational waves can be created by the superposition of a large number of independent sources. The physical processes occurring at the earliest moments of the universe certainly created a stochastic background that exists, at some level, today. This is analogous to the cosmic microwave background, which is an electromagnetic record of the early universe. The recent observations of gravitational waves by the Advanced LIGO and Advanced Virgo detectors imply that there is also a stochastic background that has been created by binary black hole and binary neutron star mergers over the history of the universe. Whether the stochastic background is observed directly, or upper limits placed on it in specific frequency bands, important astrophysical and cosmological statements about it can be made. This review will summarize the current state of research of the stochastic background, from the sources of these gravitational waves, to the current methods used to observe them. Keywords: stochastic gravitational wave background, cosmology, gravitational waves 1. Introduction Gravitational waves are a prediction of Albert Einstein from 1916 [1,2], a consequence of general relativity [3]. Just as an accelerated electric charge will create electromagnetic waves (light), accelerating mass will create gravitational waves. And almost exactly arXiv:1811.08797v1 [gr-qc] 21 Nov 2018 a century after their prediction, gravitational waves were directly observed [4] for the first time by Advanced LIGO [5, 6]. -
What Are Gravitational Waves?
The Search for Gravitational Waves Prof. Jim Hough Institute for Gravitational Research University of Glasgow Gravitation Newton’s Einstein’s Theory Theory information cannot be carried faster than “instantaneous speed of light – there action at a must be gravitational distance” radiation GW a prediction of General Relativity (1916) GW ‘rediscovered’ by Joseph Weber (1961) ‘Gravitational Waves – the experimentalist’s view’ . Gravitational waves ‘ripples in the curvature of spacetime’ that carry information about changing gravitational fields – or fluctuating strains in space of amplitude h where: h ~ L/L ‘Gravitational Waves’- possible sources Pulsed Compact Binary Coalescences NS/NS; NS/BH; BH/BH Stellar Collapse (asymmetric) to NS or BH Continuous Wave Binary stars coalescing Pulsars Low mass X-ray binaries (e.g. SCO X1) Modes and Instabilities of Neutron Stars Stochastic Inflation Cosmic Strings Supernova Science questions to be answered Fundamental physics and GR Cosmology What are the properties of gravitational . What is the history of the accelerating waves? expansion of the Universe? Is general relativity the correct theory of gravity? . Were there phase transitions in the early Universe? Is general relativity still valid under strong-gravity conditions? Astronomy and astrophysics Are Nature’s black holes the black holes How abundant are stellar-mass black holes? of general relativity? What is the central engine behind gamma- How does matter behave under extremes of density and pressure? ray bursts? Do intermediate mass