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Cascina 2003

Observing the Most Violent Events in the Universe Virgo Barry Barish Director, LIGO Virgo Inauguration 23-July-03. Cascina 2003. Michelangelo “The Battle of Cascina”. Unfinished Full Size Drawing of the Violence of War. Virgo Gravitational Waves.

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Cascina 2003

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  1. Observing the Most Violent Events in the UniverseVirgoBarry BarishDirector, LIGOVirgo Inauguration23-July-03 Cascina 2003

  2. Michelangelo“The Battle of Cascina” Unfinished Full Size Drawing of the Violence of War

  3. VirgoGravitational Waves Detecting Violent Events in the Cosmos like Colliding Black HolesCredit:: National Center for Supercomputing Applications (NCSA)

  4. A Conceptual Problem is solved ! Newton’s Theory “instantaneous action at a distance” Gmn= 8pTmn Einstein’s Theory information carried by gravitational radiation at the speed of light

  5. Einstein’s Theory of Gravitation • a necessary consequence of Special Relativity with its finite speed for information transfer • gravitational waves come from the acceleration of masses and propagate away from their sources as a space-time warpage at the speed of light gravitational radiation binary inspiral of compact objects

  6. Detectionof Gravitational Waves Gravitational Wave Astrophysical Source Terrestrial detectors Virgo, LIGO, TAMA, GEO Detectors in space LISA

  7. International Network on Earth simultaneously detect signal LIGO Virgo GEO TAMA AIGO detection confidence locate the sources decompose the polarization of gravitational waves

  8. The effect … Leonardo da Vinci’s Vitruvian man Stretch and squash in perpendicular directions at the frequency of the gravitational waves

  9. Detecting a passing wave …. Free masses

  10. Detecting a passing wave …. Interferometer

  11. The challenge …. I have greatly exaggerated the effect!! If the Vitruvian man was 4.5 light years high, he would grow by only a ‘hairs width’ Interferometer Concept

  12. As a wave passes, the arm lengths change in different ways…. Interferometer Concept • Arms in Virgo are 3km • Measure difference in length to one part in 1021 or 10-18 meters • Laser used to measure relative lengths of two orthogonal arms …causing the interference pattern to change at the photodiode Suspended Masses

  13. One meter ~ 40 inches Human hair ~ 100 microns Wavelength of light ~ 1 micron Atomic diameter 10-10 m Nuclear diameter 10-15 m Virgo sensitivity 10-18 m How Small is 10-18 Meter?

  14. The Search has Begun … • Virgo joins the international effort to detect gravitational waves and to open a new window on the Universe • On behalf of LIGO and the rest of the international community, I welcome Virgo into this exciting adventure Congratulations !!!

  15. Astrophysical Sourcessignatures • Compact binary inspiral: “chirps” • NS-NS waveforms are well described • BH-BH need better waveforms • search technique: matched templates • Supernovae / GRBs: “bursts” • burst signals in coincidence with signals in electromagnetic radiation • prompt alarm (~ one hour) with neutrino detectors • Pulsars in our galaxy: “periodic” • search for observed neutron stars (frequency, doppler shift) • all sky search (computing challenge) • r-modes • Cosmological Signal “stochastic background”

  16. Early Universe: “correlated noise” ‘Murmurs’ from the Big Bang Cosmic Microwave background WMAP 2003

  17. International NetworkLIGO Hanford Observatory MIT Caltech Livingston Observatory

  18. LIGO Livingston Observatory

  19. LIGO Hanford Observatory

  20. What Limits LIGO Sensitivity? • Seismic noise limits low frequencies • Thermal Noise limits middle frequencies • Quantum nature of light (Shot Noise) limits high frequencies • Technical issues - alignment, electronics, acoustics, etc limit us before we reach these design goals

  21. LIGO Sensitivity Livingston 4km Interferometer May 01 First Science Run 17 days - Sept 02 Jan 03 Second Science Run 59 days - April 03

  22. Detect the Earth Tide from the Sun and Moon

  23. Signals from the Early Universe • Strength specified by ratio of energy density in GWs to total energy density needed to close the universe: • Detect by cross-correlating output of two GW detectors: First LIGO Science Data Hanford - Livingston

  24. Gravitational Waves from the Early Universe E7 results projected S1 S2 LIGO Adv LIGO

  25. Gravitational Waves A New Window on the Universe Virgoand its international partners will provide a new way to view the dynamics of the Universe

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