1

Welcome to LIGO!

What Does the Universe Look Like?

2

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

6

Orion Nebula in the Infrared

Radio Waves

Micro-waves

Infrared Visible UV X-ray Gamma

7

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

9

What about Black Holes?Courtesy: Wikimedia

Radio Waves

Micro-waves

Infrared Visible UV X-ray Gamma ??

10

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

11

12

The Heart of LIGO – Vacuum Equipment Areas

View inside Corner Station

Standing at vertex beam

splitter

13

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

14

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.

15

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

16

17

18

19

24

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

25

Sources of Gravitational Waves: Supernovae

26

The Spinning of Neutron Star Pulsars

27

Inspirals -- the Loudest Sources

28

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?

30

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

Laser

Beam Splitter

End Mirror End Mirror

Screen

31

Fabry Perot cavities and power recycling provide additional sensitivity

Laser

signal

33

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

34

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

36

Vacuum chambers provide quiethomes for the mirrors

View inside Corner Station

Standing at vertex beam

splitter

37

Evacuated Beam Tubes Provide Clear Path for Light

38

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

39

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

40

Suspended Core Optic

41

BSC Passive Vibration Isolation

42

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

44

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

45

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

46

Projected strain sensitivity for eLIGO

Enhanced LIGO

47

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!

48

Welcome to LIGO!

49

CourtesySOHO/NASA/ESA

The Sun in H-alpha (visible)

Radio Waves

Micro-waves

Infrared Visible UV X-ray Gamma

50

Image courtesy of Astro-1 and Robert Gendler

M81 in UV and visible

51

Image courtesy of ESA/ROSAT

The Crab in X-ray