1 welcome to ligo!. what does the universe look like? 2

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Welcome to LIGO!

What Does the Universe Look Like?

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The Constellation Orion (The Hunter)

Credit:thcphotography.com

Radio Waves

Micro-waves

Infrared Visible UV X-ray Gamma

Orion in the UV

Credit:Midcourse Space Experiment, Johns Hopkins

Radio Waves

Micro-waves

Infrared Visible UV X-ray Gamma

Zoom in - The Orion Nebula

through the Hubble Space Telescope

Radio Waves

Micro-waves

Infrared Visible UV X-ray Gamma

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Orion Nebula in the Infrared

Radio Waves

Micro-waves

Infrared Visible UV X-ray Gamma

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Orion Nebula in Radio Waves

Credit:NRAO

Radio Waves

Micro-waves

Infrared Visible UV X-ray Gamma

Orion Nebula in X-rays

Credit: NASA/CXC/Penn State/E.Feigelson & K.Getman et al

Radio Waves

Micro-waves

Infrared Visible UV X-ray Gamma

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What about Black Holes?Courtesy: Wikimedia

Radio Waves

Micro-waves

Infrared Visible UV X-ray Gamma ??

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LIGO – A New Way to Look at (or Listen to) the Universe

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The Heart of LIGO – Vacuum Equipment Areas

View inside Corner Station

Standing at vertex beam

splitter

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Local sensors/actuators provide damping and control forces

Mirror is balanced on 1/100th inchdiameter wire to 1/100th degree of arc

Optics suspended as simple pendulums

Pendulum suspensions give mirrors freedom of movement in the LIGO frequency band

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LIGO (Washington) LIGO (Louisiana)

The Laser InterferometerGravitational-Wave Observatory

Brought to you by the National Science Foundation; operated by Caltech and MIT; the research focus for about 500 LIGO Science Collaboration members

worldwide.

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Part of Future International Detector Network

LIGO

Simultaneously detect signal (within msec)

detection confidence locate the sources

decompose the polarization of gravitational waves

GEO VirgoTAMA

AIGO

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LIGO hunts for ripples in the curvature of space – gravitational waves

Gravitational waves are ripples in the fabric of space. These ripples

come from rapid motions of large

concentrations of matter or energy.

Rendering of space stirred by two orbiting black holes:

By the time gravitational waves pass the earth, their effects are vanishingly small. Our detector must be sensitive enough to measure these effects

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Sources of Gravitational Waves: Supernovae

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The Spinning of Neutron Star Pulsars

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Inspirals -- the Loudest Sources

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LIGO listens for ripples in the curvature of space. These will produce vibrations of the interference pattern in the interferometer. Photosensors will record the vibrations.

Inspiraling Neutron Stars

Inspiraling Black Holes

What might be the “sound” of gravitational waves?

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The basic Michelson design provides the ability to monitor a circle of space

Laser

Beam Splitter

End Mirror End Mirror

Screen

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Fabry Perot cavities and power recycling provide additional sensitivity

Laser

signal

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Enhanced LIGO – transition from 10W to 35W of laser power

• Prepared by AEI/LZH (Germany)

• World-leading performance in frequency and amplitude stability

• Base unit for Advanced LIGO

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More laser power requires enhanced input optics

• Faraday isolator re-polarizes and dumps returning light before it enters the laser enclosure

• IO R&D from University of Florida

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Vacuum chambers provide quiethomes for the mirrors

View inside Corner Station

Standing at vertex beam

splitter

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Evacuated Beam Tubes Provide Clear Path for Light

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Local sensors/actuators provide damping and control forces

Mirror is balanced on 1/100th inchdiameter wire to 1/100th degree of arc

Optics suspended as simple pendulums

Pendulum suspensions give mirrors freedom of movement in the LIGO frequency band

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Core Optics

• Substrates: SiO2» 25 cm Diameter, 10 cm thick

» Homogeneity < 5 x 10-7

» Internal mode Q’s > 2 x 106

• Polishing» Surface uniformity < 1 nm rms

» Radii of curvature matched < 3%

• Coating» Scatter < 50 ppm

» Absorption < 2 ppm

» Uniformity <10-3

• Production involved 6 companies, NIST, and LIGO

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Suspended Core Optic

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BSC Passive Vibration Isolation

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Active vibration isolation in HAM 6 (detection chamber)

• Signals from on-board sensors are used in the actuation scheme

• ISI will provide a quiet platform for GW photodiodes

• Stanford R&D

1/22/2009 43

ISI Install

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Isolated and suspended output mode cleaner

• OMC will remove ‘junk’ from detection port light

• In-vacuum (isolated) photodiodes tuned for DC readout scheme

• OMC – Caltech, GEO

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Additional eLIGO changes

• Upgraded Thermal compensation on inner mirrors• Replace viton stop tips with silica tips• Replace selected control system magnets with lower-

noise versions• Mount baffles to reduce stray light• Intense commissioning continues to precede the start

of S6

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Projected strain sensitivity for eLIGO

Enhanced LIGO

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LIGO is operated by Caltech and MIT for the National Science Foundation

• NSF Cooperative Agreement # NSF-PHY-0757058• LIGO’s research efforts are directed by the LIGO

Scientific Collaboration, composed of roughly 600 researchers at more than 40 domestic and international institutions.

• Apply for a summer research internship!

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Welcome to LIGO!

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CourtesySOHO/NASA/ESA

The Sun in H-alpha (visible)

Radio Waves

Micro-waves

Infrared Visible UV X-ray Gamma

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Image courtesy of Astro-1 and Robert Gendler

M81 in UV and visible

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Image courtesy of ESA/ROSAT

The Crab in X-ray