Detection of Gravitational Collapse J
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Generation of Angular Momentum in Cold Gravitational Collapse
A&A 585, A139 (2016) Astronomy DOI: 10.1051/0004-6361/201526756 & c ESO 2016 Astrophysics Generation of angular momentum in cold gravitational collapse D. Benhaiem1,M.Joyce2,3, F. Sylos Labini4,1,5, and T. Worrakitpoonpon6 1 Istituto dei Sistemi Complessi Consiglio Nazionale delle Ricerche, via dei Taurini 19, 00185 Rome, Italy e-mail: [email protected] 2 UPMC Univ. Paris 06, UMR 7585, LPNHE, 75005 Paris, France 3 CNRS IN2P3, UMR 7585, LPNHE, 75005 Paris, France 4 Centro Studi e Ricerche Enrico Fermi, Via Panisperna 89 A, Compendio del Viminale, 00184 Rome, Italy 5 INFN Unit Rome 1, Dipartimento di Fisica, Universitá di Roma Sapienza, Piazzale Aldo Moro 2, 00185 Roma, Italy 6 Faculty of Science and Technology, Rajamangala University of Technology Suvarnabhumi, Nonthaburi Campus, 11000 Nonthaburi, Thailand Received 16 June 2015 / Accepted 4 November 2015 ABSTRACT During the violent relaxation of a self-gravitating system, a significant fraction of its mass may be ejected. If the time-varying gravi- tational field also breaks spherical symmetry, this mass can potentially carry angular momentum. Thus, starting initial configurations with zero angular momentum can, in principle, lead to a bound virialised system with non-zero angular momentum. Using numerical simulations we explore here how much angular momentum can be generated in a virialised structure in this way, starting from con- figurations of cold particles that are very close to spherically symmetric. For the initial configurations in which spherical symmetry is broken only by the Poissonian fluctuations associated with the finite particle number N, with N in range 103 to 105, we find that the relaxed structures have standard “spin” parameters λ ∼ 10−3, and decreasing slowly with N. -
Special and General Relativity with Applications to White Dwarfs, Neutron Stars and Black Holes
Norman K. Glendenning Special and General Relativity With Applications to White Dwarfs, Neutron Stars and Black Holes First Edition 42) Springer Contents Preface vii 1 Introduction 1 1.1 Compact Stars 2 1.2 Compact Stars and Relativistic Physics 5 1.3 Compact Stars and Dense-Matter Physics 6 2 Special Relativity 9 2.1 Lorentz Invariance 11 2.1.1 Lorentz transformations 11 2.1.2 Time Dilation 14 2.1.3 Covariant vectors 14 2.1.4 Energy and Momentum 16 2.1.5 Energy-momentum tensor of a perfect fluid 17 2.1.6 Light cone 18 3 General Relativity 19 3.1 Scalars, Vectors, and Tensors in Curvilinear Coordinates 20 3.1.1 Photon in a gravitational field 28 3.1.2 Tidal gravity 29 3.1.3 Curvature of spacetime 30 3.1.4 Energy conservation and curvature 30 3.2 Gravity 32 3.2.1 Einstein's Discovery 32 3.2.2 Particle Motion in an Arbitrary Gravitational Field 32 3.2.3 Mathematical definition of local Lorentz frames . 35 3.2.4 Geodesics 36 3.2.5 Comparison with Newton's gravity 38 3.3 Covariance 39 3.3.1 Principle of general covariance 39 3.3.2 Covariant differentiation 40 3.3.3 Geodesic equation from covariance principle 41 3.3.4 Covariant divergente and conserved quantities . 42 3.4 Riemann Curvature Tensor 45 x Contents 3.4.1 Second covariant derivative of scalars and vectors 45 3.4.2 Symmetries of the Riemann tensor 46 3.4.3 Test for flatness 47 3.4.4 Second covariant derivative of tensors 47 3.4.5 Bianchi identities 48 3.4.6 Einstein tensor 48 3.5 Einstein's Field Equations 50 3.6 Relativistic Stars 52 3.6.1 Metric in static isotropic spacetime 53 -
Stellar Equilibrium Vs. Gravitational Collapse
Eur. Phys. J. H https://doi.org/10.1140/epjh/e2019-100045-x THE EUROPEAN PHYSICAL JOURNAL H Stellar equilibrium vs. gravitational collapse Carla Rodrigues Almeidaa Department I Max Planck Institute for the History of Science, Boltzmannstraße 22, 14195 Berlin, Germany Received 26 September 2019 / Received in final form 12 December 2019 Published online 11 February 2020 c The Author(s) 2020. This article is published with open access at Springerlink.com Abstract. The idea of gravitational collapse can be traced back to the first solution of Einstein's equations, but in these early stages, com- pelling evidence to support this idea was lacking. Furthermore, there were many theoretical gaps underlying the conviction that a star could not contract beyond its critical radius. The philosophical views of the early 20th century, especially those of Sir Arthur S. Eddington, imposed equilibrium as an almost unquestionable condition on theoretical mod- els describing stars. This paper is a historical and epistemological account of the theoretical defiance of this equilibrium hypothesis, with a novel reassessment of J.R. Oppenheimer's work on astrophysics. 1 Introduction Gravitationally collapsed objects are the conceptual precursor to black holes, and their history sheds light on how such a counter-intuitive idea was accepted long before there was any concrete proof of their existence. A black hole is a strong field structure of space-time surrounded by a unidirectional membrane that encloses a singularity. General relativity (GR) predicts that massive enough bodies will collapse into black holes. In fact, the first solution of Einstein's field equations implies the existence of black holes, but this conclusion was not reached at the time because the necessary logical steps were not as straightforward as they appear today. -
Collapse of an Unstable Neutron Star to a Black Hole Matthias Hanauske (E-Mail:[email protected], Office: 02.232)
Experiments in Computer Simulations : Collapse of an unstable Neutron Star to a Black Hole Matthias Hanauske (e-mail:[email protected], office: 02.232) 0 Class Information • application form : { if you want to do this experiment, please register via e-mail to me no later than on the last Wednesday before the week in which you want to do the experiment; your e-mail should include the following information: (1) student number, (2) full name, (3) e-mail address. • intensive course : { 12 [hours] = 6 [hours/week] × 2 [weeks]. • when : { Monday 9-16, two subsequent weeks upon individual arrangement with me; other time slots may be arranged with me individually. • where : { Pool Room 01.120. • preparation : { an account for you on the \FUCHS" cluster of the CSC (http://csc.uni-frankfurt.de/) will be provided; please read the quick starting guide on the CSC web pages before starting the simulation. • required skill : { basic Linux knowledge. • using software : { Einstein Toolkit [5]. { gnuplot (http://www.gnuplot.info/) { pygraph (https://bitbucket.org/dradice/pygraph). { python (https://www.python.org/) and matplotlib (http://matplotlib.org/). { Mathematica (http://www.wolfram.com/mathematica/). 1 1 Introduction Neutron stars are beside white dwarfs and black holes the potential final states of the evo- lution of a normal star. These extremely dense astrophysical objects, which are formed in the center of a supernova explosion, represent the last stable state before the matter collapses to a black hole. Due to their large magnetic fields (up to 1011 Tesla) and fast rotation (up to 640 rotations in one second) neutron stars emit a certain electromagnetic spectrum. -
LIGO Detector and Hardware Introduction
LIGO Detector and Hardware Introduction Virtual Open Data Workshop May 2020 LIGO-G2000795 Outline • Introduction 45W • Interferometry 40W 1.6kW 200kW Locking Optical cavities • Hardware • Noise Fundamental Technical • Commissioning/Observation Runs • Future Detector Plans • Bibliography Gravitational Waves • Metric tensor perturbation in GR = + 2 polarization in GR Scalar and other possible waves ℎ • Free falling masses • Change in laser propagation time • Phase difference in light ∝ ℎ • Interferometry detects phase difference ∝ ℎ • Astronomical Sources Modeling Modeled Unmodeled /Length Modeled vs Unmodeled Short Inspirals (BBH, Bursts Short vs Long BNS, BH/NS) (Supernova) Long Continuous Waves Stochastic Known vs Unknown (Pulsars) Background Sensitivity Estimate • Strain from single photon: = 10 2 • Need strain 10 � −10 ℎ ≅ • Shot noise SNR− 22 = 10 improvement,∝ � 10 photons At1 1002 Hz equivalent to power24 of 20 MW • • With 200 W of input laser power, 45W 200kW 40W 1.6kW requires power gain of 100,000 Total optical gain in LIGO is ~50,000 Ignores other noise sources Gravitational Wave Detector Network GEO 600: Germany Virgo: Italy KAGRA: Japan Interferometry • Book by Peter Saulson • Michelson interferometer Fringe splitting • Fabry-Perot arms Cavity pole, = ⁄4ℱ • Pound-Drever-Hall locking 45W 200kW 40W 1.6kW Match laser frequency to cavity length RF modulation with EOM • Feedback and controls Other LIGO Cavities • Mode cleaners Input and output 45W 200kW 40W 1.6kW Single Gauss-Laguerre mode • Power recycling Output dark -
LIGO Listens for Gravitational Waves
Probing Physics and Astrophysics with Gravitational Wave Observations Peter Shawhan Mid-Atlantic Senior Physicists’ Group January 18, 2017 GOES-8 image produced by M. Jentoft-Nilsen, F. Hasler, D. Chesters LIGO-G1600320-v10 (NASA/Goddard) and T. Nielsen (Univ. of Hawaii) NEWS FLASH: We detected gravitational waves 2 We = the LIGO Scientific Collaboration ))) together with the Virgo Collaboration ))) … using the LIGO* Observatories * LIGO = Laser Interferometer Gravitational-wave Observatory LIGO Hanford LIGO Livingston 4 ))) … after the Advanced LIGO Upgrade Comprehensive upgrade of Initial LIGO instrumentation in same vacuum system Higher-power laser Larger mirrors First Advanced LIGO Higher finesse arm cavities observing run, “O1”, was Stable recycling cavities Sep 2015 to Jan 2016 Signal recycling mirror Output mode cleaner Improvements and more … 5 ))) GW150914 Signal arrived 7 ms earlier at L1 Bandpassfiltered 6 ))) Looks just like a binary black hole merger! Bandpass filtered Matches well to BBH template when filtered the same way 7 ))) Announcing the Detection 8 ))) A Big Splash in February with both the scientific community and the general public! • Press conference • PRL web site • Twitter • Facebook • Newspapers & magazines • YouTube videos • The Late Show, SNL, … 9 A long-awaited confirmation 10 ((( Gravitational Waves ))) Predicted to exist by Einstein’s general theory of relativity … which says that gravity is really an effect of “curvature” in the geometry of space-time, caused by the presence of any object with mass Expressed -
Swift J164449. 3+ 573451 Event: Generation in the Collapsing Star
Swift J164449.3+573451 event: generation in the collapsing star cluster? V.I. Dokuchaev∗ and Yu.N. Eroshenko† Institute for Nuclear Research of the Russian Academy of Sciences 60th October Anniversary Prospect 7a, 117312 Moscow, Russia (Dated: June 27, 2018) We discuss the multiband energy release in a model of a collapsing galactic nucleus, and we try to interpret the unique super-long cosmic gamma-ray event Swift J164449.3+573451 (GRB 110328A by early classification) in this scenario. Neutron stars and stellar-mass black holes can form evolutionary a compact self-gravitating subsystem in the galactic center. Collisions and merges of these stellar remnants during an avalanche contraction and collapse of the cluster core can produce powerful events in different bands due to several mechanisms. Collisions of neutron stars and stellar-mass black holes can generate gamma-ray bursts (GRBs) similar to the ordinary models of short GRB origin. The bright peaks during the first two days may also be a consequence of multiple matter supply (due to matter release in the collisions) and accretion onto the forming supermassive black hole. Numerous smaller peaks and later quasi-steady radiation can arise from gravitational lensing, late accretion of gas onto the supermassive black hole, and from particle acceleration by shock waves. Even if this model will not reproduce exactly all the Swift J164449.3+573451 properties in future observations, such collapses of galactic nuclei can be available for detection in other events. PACS numbers: 98.54.Cm, 98.70.Rz Keywords: galactic nuclei; neutron stars; gamma-ray bursts I. INTRODUCTION ters of stellar remnants can form in the course of evolu- tion due to mass segregationsinking of the most massive On March 28, 2011, the Swift’s Burst Alert Telescope stars to the center and their explosions as supernovae [9– detected the unusual super-long gamma-ray event Swift 11]. -
Fuzzy Blackholes Anand Murugan Pomona College
Claremont Colleges Scholarship @ Claremont Pomona Senior Theses Pomona Student Scholarship 2007 Fuzzy Blackholes Anand Murugan Pomona College Recommended Citation Murugan, Anand, "Fuzzy Blackholes" (2007). Pomona Senior Theses. 21. http://scholarship.claremont.edu/pomona_theses/21 This Open Access Senior Thesis is brought to you for free and open access by the Pomona Student Scholarship at Scholarship @ Claremont. It has been accepted for inclusion in Pomona Senior Theses by an authorized administrator of Scholarship @ Claremont. For more information, please contact [email protected]. Fuzzy Blackholes Anand Murugan Advisor : Prof. Vatche Sahakian May 1, 2007 Contents 1 Introduction 2 2 Background 3 2.1 String Theory And Her Mothers, Sisters and Daughters . 3 2.2 Black Holes And Their Properties . 5 2.3Holography................................ 7 2.4NCSYMs................................. 9 3 Fuzzy Black Holes 12 3.1 Formation of the Fuzzy Horizon . 12 3.2TheNCSYM............................... 13 3.3 The Gravitational Dual . 14 3.4 The Decoupling Limit . 16 3.5 Phase Structure . 18 3.6 Stabilization . 19 4 Brane Interaction 21 4.1 Setup of Problem . 21 4.2Analysis.................................. 22 5 Conclusions 23 1 Chapter 1 Introduction The fuzzball model of a black hole is an attempt to resolve the many paradoxes and puzzles of black hole physics that have revealed themselves over the last century. These badly behaved solutions of general relativity have given physicists one of the few laboratories to test candidate quantum theories of gravity. Though little is known about exactly what lies beyond the event horizon, and what the ultimate fate of matter that falls in to a black hole is, we know a few intriguing and elegant semi-classical results that have kept physicists occupied. -
Joseph Weber's Contribution to Gravitational Waves and Neutrinos
Firenze University Press www.fupress.com/substantia Historical Article New Astronomical Observations: Joseph Weber’s Contribution to Gravitational Waves Citation: S. Gottardo (2017) New Astronomical Observations: Joseph and Neutrinos Detection Weber’s Contribution to Gravitational Waves and Neutrinos Detection. Sub- stantia 1(1): 61-67. doi: 10.13128/Sub- stantia-13 Stefano Gottardo Copyright: © 2017 S. Gottardo.This European Laboratory for Nonlinear Spectroscopy (LENS), 50019 Sesto Fiorentino (Flor- is an open access, peer-reviewed arti- ence), Italy cle published by Firenze University E-mail: [email protected] Press (http://www.fupress.com/substan- tia) and distribuited under distributed under the terms of the Creative Com- Abstract. Joseph Weber, form Maryland University, was a pioneer in the experimen- mons Attribution License, which per- tal research of gravitational waves and neutrinos. Today these two techniques are very mits unrestricted use, distribution, and promising for astronomical observation, since will allow to observe astrophysical phe- reproduction in any medium, provided nomena under a new light. We review here almost 30 years of Weber’s career spent the original author and source are on gravity waves and neutrinos; Weber’s experimental results were strongly criticized credited. by the international community, but his research, despite critics, boosted the brand Data Availability Statement: All rel- new (in mid-sixties of last century) research field of gravity waves to become one of evant data are within the paper and its the most important in XXI century. On neutrino side, he found an unorthodox way Supporting Information files. to reduce the size of detectors typically huge and he claimed to observe neutrinos flux with a small pure crystal of sapphire. -
Exact Solutions for Spherically Gravitational Collapse Around A
Exact solutions for spherically gravitational collapse around a black hole: the effect of tangential pressure Zhao Sheng-Xian(赵声贤)1,3, Zhang Shuang-Nan(张双南)1,2,3† 1 Key Laboratory of Space Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, China 2 Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Beijing 100049, China 3 University of Chinese Academy of Sciences, Beijing 100049, China Abstract: Spherically gravitational collapse towards a black hole with non-zero tangential pressure is studied. Exact solutions corresponding to different equations of state are given. We find that when taking the tangential pressure into account, the exact solutions have three qualitatively different endings. For positive tangential pressure, the shell around a black hole may eventually collapse onto the black hole, or expand to infinity, or have a static but unstable solution, depending on the combination of black hole mass, mass of the shell and the pressure parameter. For vanishing or negative pressure, the shell will collapse onto the black hole. For all eventually collapsing solutions, the shell will cross the event horizon, instead of accumulating outside the event horizon, even if clocked by a distant stationary observer. Keywords: black holes, gravitational collapse, general relativity 1. Introduction In 1939 Oppenheimer and Snyder [1] studied the gravitational collapse of a homogeneous spherically symmetric and pressureless dust cloud, which initiated the study of gravitational collapse. In the work of Oppenheimer and Snyder (1939) [1], they predicted the phenomenon of “frozen star”, which states that a test particle falling towards a black hole will be eventually frozen near the black hole with an arbitrarily small distance from the event horizon for an observer at infinity, though the particle will indeed cross the event horizon and reach the singularity at the center within finite time in the comoving coordinates. -
Current Status of GW Detection Wei-Tou Ni 倪维斗 National Tsing Hua University Refs: (I) S
Current Status of GW Detection Wei-Tou Ni 倪维斗 National Tsing Hua University Refs: (i) S. Kuroyanagi, L-W Luo and WTN, GW sensitivities over all frequency band (ii) K Kuroda, WTN, WP Pan, IJMPD 24 (2015) 1530031 (iii) LIGO/Virgo Collaborations, GWTC-1: A GW Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo O1 & O2 (iv) LIGO/Virgo Collaborations, BBH Population Properties Inferred from O1 & O2 Observing Runs (v) WTN, GW detection in space IJMPD 25 (2016) 1530002 ……… 2018/12/28 NCTS Hsinchu Current Status of GW Detection Ni 1 Among other things, 20th Century will be memorized by the advancement of fundamental physical theory and the experimental precision • 1915 General Relativity, 1916 Gravitational Waves (Einstein) • Early 1900’s: Strain Measurement precision 10-6 • 1960’s: Strain Measurement precision 10-16 Weber Bar (50 Years ago) 10 orders of gap abridged • Cryogenic Resonators; Laser Interferometry • Early 2000’s: Strain Measurement precision 10-21 • 2015: 10-22 strain precision on Detection of GWs 2018/12/28 NCTS Hsinchu Current Status of GW Detection Ni 2 LIGO Ground-based GW detectors KAGRA VIRGO ET 2018/12/28 NCTS Hsinchu Current Status of GW Detection Ni 3 2016 February 11 Announcement of first (direct) detection of Black Holes and GWs 2018/12/28 NCTS Hsinchu Current Status of GW Detection Ni 4 2017.08.17 NSB coalescence, ApJ 848 2018/12/28 NCTS Hsinchu Current Status of GW Detection Ni 5 - Population model: A. Power law p(m) m , mmin=5M, B. Power law m-, C. A mixture of a power law and a Gaussian distribution -
Full TIPP 2011 Program Book
Second International Conference on Technology and Instrumentation in Particle Physics June 9-14, 2011 Program & Abstracts Sheraton Chicago Hotel and Towers, Chicago IL ii TIPP 2011 — June 9-14, 2011 Table of Contents Acknowledgements .................................................................................................................................... v Session Conveners ...................................................................................................................................vii Session Chairs .......................................................................................................................................... ix Agenda ....................................................................................................................................................... 1 Abstracts .................................................................................................................................................. 35 Poster Abstracts ..................................................................................................................................... 197 Abstract Index ........................................................................................................................................ 231 Poster Index ........................................................................................................................................... 247 Author List .............................................................................................................................................