Overview of LIGO

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Overview of LIGO
Mark Coles Observatory Head LIGO Livingston
Observatory Caltech
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LIGO Laser Interferometer Gravitational-wave
Observatory

• LIGO consists of three laser interferometers
  located at two sites separated by 3000 km.
• The other two are at the same facility in eastern
  Washington, on the Department of Energys Hanford
  Nuclear Reservation,
• Operated by Caltech in partnership with MIT
  through a cooperative agreement with the National
  Science Foundation.

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The LIGO Science Collaboration scientific body
of LIGO which defines science goals, supports
their achievement.
LSC Membership 35 institutions gt 350
collaborators
International India, Russia, Germany, U.K,
Japan and Australia.

• University of Adelaide ACIGA
• Australian National University ACIGA
• California State Dominquez Hills
• Caltech LIGO
• Caltech Experimental Gravitation CEGG
• Caltech Theory CART
• University of Cardiff GEO
• Carleton College
• Cornell University
• University of Florida _at_ Gainesville
• Glasgow University GEO
• University of Hannover GEO
• Harvard-Smithsonian
• India-IUCAA
• IAP Nizhny Novgorod
• Iowa State University
• Joint Institute of Laboratory Astrophysics

• LIGO Livingston LIGOLA
• LIGO Hanford LIGOWA
• Louisiana State University
• Louisiana Tech University
• Loyola Univ of New Orleans
• MIT LIGO
• Max Planck (Garching) GEO
• Max Planck (Potsdam) GEO
• University of Michigan
• Moscow State University
• NAOJ - TAMA
• University of Oregon
• Pennsylvania State University Exp
• Pennsylvania State University Theory
• Southern University
• Stanford University
• University of Texas_at_Brownsville
• University of Western Australia ACIGA
• University of Wisconsin_at_Milwaukee

The international partners are involved in all
aspects of the LIGO research program.
GWIC Gravitational Wave International Committee
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International network of gravitational wave
interferometers now being brought into operation
Virgo
GEO
LIGO
TAMA
Coincident detection to enhance detection
confidence source location decompose the
polarization of gravitational waves
AIGO
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LSU Participation in LIGO is broad and well
integrated

• Faculty research and student participation
• Experimentally
• Active seismic isolation
• Wave front sensors
• Interferometer characterization
• Data analysis
• Theoretically
• Quantitative descriptions of astrophysical
  sources of gravity waves
• Infrastructure support
• Legal support for site acquisition and permits
• liaison with state (access road)
• Internet connection and support at LSU, and with
  Bell South
• Outreach activities
• 16 inch LTIF telescope (with LSU Physics Prof.
  Greg Guzik)
• We want to encourage additional joint activities
  to strengthen our partnership.

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Some History...

• Electromagnetic observation of the universe with
  photons
• Visible radiation
• atoms near surface of stars,
• surrounding gas clouds
• reflected radiation from planets and moons
• Other frequencies radio, x-ray, gamma ray
• Particle astrophysics
• cosmic rays
• neutrinos (solar neutrinos, SN1987 A)
• What about gravity as a messenger of
  astrophysical information?

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Einsteins Theory of Gravitation gravitational
waves

• a necessary consequence of Special Relativity
  with its finite speed for information transfer
• Einstein in 1916 and 1918 put forward the
  formulation of gravitational waves in General
  Relativity
• time dependent gravitational fields 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
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GWs from Hulse-Taylor binary
emission of gravitational waves by compact binary
system

• Only 7 kpc away
• period speeds up 14 sec from 1975-94
• orbital energy loss ?shortening of period
• deviation grows quadratically with time
• beautiful agreement (lt0.4 discrepancy) with GR
  prediction of energy loss due to gravitational
  radiation

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Only positive mass exists, so dipole
displacements are not allowed by conservation of
momentum
quadrupole radiation is lowest order radiation
multipole
Gravitational source from quadrupole deformation
of a sphere
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Gravitational Wave Antenna quadrupole strain
sensitivity
Displacement 10-19 meters for 4 km path!
Initial position of freely suspended test
mass Displaced test mass position
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Status

• First 16 day Science Run now in progress.
• New high water mark for gravitational wave
  searches.
• 9th in a series of data runs to check and
  characterize the detectors, software, procedures.

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Plans

• Further commissioning of interferometer control
  systems to achieve design sensitivity
• Plan to collect at least one year of integrated
  coincident data during 2003-2006
• Developing plans and proposals to install a major
  upgrade at both sites following data collection
• Development of technologies for improved
  interferometers underway
• Multiple pendulum suspensions
• Active seismic isolation
• High power lasers and optics

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In an inertial reference frame Positive and
negative charge allows dipole radiation
Electromagnetic Radiation
Wave propagation direction
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