40
LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

  • View
    216

  • Download
    0

Embed Size (px)

Citation preview

Page 1: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO-G030009-01-W

"Colliding Black Holes"

Credit:National Center for Supercomputing Applications (NCSA)

Intro to LIGO

Fred Raab,

LIGO Hanford Observatory

Page 2: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 2LIGO-G030009-01-W

Outline

What LIGO is Relativity connection Terrestrial detector band How the detectors work LIGO searches

Page 3: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 3LIGO-G030009-01-W

LIGO (Washington) LIGO (Louisiana)

The Laser InterferometerGravitational-Wave Observatory

Funded by the National Science Foundation; operated by Caltech and MIT; the research focus for more than 500 LIGO Science Collaboration members worldwide.

Page 4: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

The LIGO Observatories

Adapted from “The Blue Marble: Land Surface, Ocean Color and Sea Ice” at visibleearth.nasa.govNASA Goddard Space Flight Center Image by Reto Stöckli (land surface, shallow water, clouds). Enhancements by Robert Simmon (ocean color, compositing, 3D globes, animation). Data and technical support: MODIS Land Group; MODIS Science Data Support Team; MODIS Atmosphere Group; MODIS Ocean Group Additional data: USGS EROS Data Center (topography); USGS Terrestrial Remote Sensing Flagstaff Field Center (Antarctica); Defense Meteorological Satellite Program (city lights).

LIGO Hanford Observatory (LHO)H1 : 4 km armsH2 : 2 km arms

LIGO Livingston Observatory (LLO)L1 : 4 km arms

10 ms

Page 5: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 5LIGO-G030009-01-W

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

Page 6: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 6LIGO-G030009-01-W

John Wheeler’s Summary of General Relativity Theory

Page 7: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 7LIGO-G030009-01-W

The New Wrinkle on Equivalence

Not only the path of matter, but even the path of light is affected by gravity from massive objects

Einstein Cross

Photo credit: NASA and ESA

A massive object shifts apparent position of a star

Page 8: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 8LIGO-G030009-01-W

Gravitational Waves

Gravitational waves are ripples in space when it is stirred up by rapid motions of large concentrations of matter or energy

Rendering of space stirred by two orbiting black holes:

Page 9: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 9LIGO-G030009-01-W

Gravitational Collapse and Its Outcomes Present LIGO Opportunities

fGW > few Hz accessible from earth

fGW < several kHz interesting for compact objects

Page 10: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 10LIGO-G030009-01-W

Catching WavesFrom Black Holes

Sketches courtesy of Kip Thorne

Page 11: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 11LIGO-G030009-01-W

Detection of Energy Loss Caused By Gravitational Radiation

In 1974, J. Taylor and R. Hulse discovered a pulsar orbiting a companion neutron star. This “binary pulsar” provides some of the best tests of General Relativity. Theory predicts the orbital period of 8 hours should change as energy is carried away by gravitational waves.

Taylor and Hulse were awarded the 1993 Nobel Prize for Physics for this work.

Page 12: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 12LIGO-G030009-01-W

Potential sources

Inspiral & merger of compact binaries Ringdown of newly formed black holes Supernovae (especially non-axisymmetric core

collapse), Gamma-ray bursters Neutron-star (strange-quark-star ?) wobbles or

quakes Accreting compact systems Stochastic signals or cosmological or astrophysical

origin Cosmic string signals

Page 13: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO-G030009-01-W

How does LIGO detect spacetime vibrations?

Page 14: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 14LIGO-G030009-01-W

Basic Signature of Gravitational Waves for All Detectors

Page 15: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 15LIGO-G030009-01-W

Laser

Beam Splitter

End Mirror End Mirror

ScreenViewing

Sketch of a Michelson Interferometer

Page 16: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 16LIGO-G030009-01-W

Recycling Mirror

Optical

Cavity

4 km or2-1/2

miles

Beam Splitter

Laser

Photodetector

Fabry-Perot-Michelson with Power Recycling

Page 17: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 17LIGO-G030009-01-W

Spacetime is Stiff!

=> Wave can carry huge energy with miniscule amplitude!

h ~ (G/c4) (ENS/r)

Page 18: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 18LIGO-G030009-01-W

Some of the Technical Challenges

Typical Strains < 10-21 at Earth ~ 1 hair’s width at 4 light years

Understand displacement fluctuations of 4-km arms at the millifermi level (1/1000th of a proton diameter)

Control arm lengths to 10-13 meters RMS Detect optical phase changes of ~ 10-10 radians Hold mirror alignments to 10-8 radians Engineer structures to mitigate recoil from atomic

vibrations in suspended mirrors

Page 19: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 19LIGO-G030009-01-W

Vacuum Chambers Provide Quiet Homes for Mirrors

View inside Corner Station

Standing at vertex beam splitter

Page 20: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 20LIGO-G030009-01-W

Vibration Isolation Systems

» Reduce in-band seismic motion by 4 - 6 orders of magnitude» Little or no attenuation below 10Hz» Large range actuation for initial alignment and drift compensation» Quiet actuation to correct for Earth tides and microseism at 0.15 Hz during

observation

HAM Chamber BSC Chamber

Page 21: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 21LIGO-G030009-01-W

Seismic Isolation – Springs and Masses

damped springcross section

Page 22: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 22LIGO-G030009-01-W

Seismic System Performance

102

100

10-2

10-4

10-6

10-8

10-10

Horizontal

Vertical

10-6

HAM stackin air

BSC stackin vacuum

Page 23: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 23LIGO-G030009-01-W

Evacuated Beam Tubes Provide Clear Path for Light

Page 24: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 24LIGO-G030009-01-W

All-Solid-State Nd:YAG Laser

Custom-built10 W Nd:YAG Laser,

joint development with Lightwave Electronics

(now commercial product)

Frequency reference cavity (inside oven)

Cavity for defining beam geometry,

joint development withStanford

Page 25: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 25LIGO-G030009-01-W

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

Page 26: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 26LIGO-G030009-01-W

Core Optics Suspension and Control

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

Page 27: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 27LIGO-G030009-01-W

Suspended Mirror Approximates a Free Mass Above Resonance

Page 28: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 28LIGO-G030009-01-W

Background Forces in GW Band = Thermal Noise ~ kBT/mode

Strategy: Compress energy into narrow resonance outside band of interest require high mechanical Q, low friction

xrms 10-11 mf < 1 Hz

xrms 210-17 mf ~ 350 Hz

xrms 510-16 mf 10 kHz

Page 29: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 29LIGO-G030009-01-W

Thermal Noise Observed in 1st Violins on H2, L1 During S1

Almost good enough for tracking calibration.

Page 30: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 30LIGO-G030009-01-W

Feedback & Control for Mirrors and Light

Damp suspended mirrors to vibration-isolated tables» 14 mirrors (pos, pit, yaw, side) = 56 loops

Damp mirror angles to lab floor using optical levers» 7 mirrors (pit, yaw) = 14 loops

Pre-stabilized laser» (frequency, intensity, pre-mode-cleaner) = 3 loops

Cavity length control» (mode-cleaner, common-mode frequency, common-arm, differential

arm, michelson, power-recycling) = 6 loops

Wave-front sensing/control» 7 mirrors (pit, yaw) = 14 loops

Beam-centering control» 2 arms (pit, yaw) = 4 loops

Page 31: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 31LIGO-G030009-01-W

Time Line

First Science Data

Inauguration

19993Q 4Q

20001Q 2Q 3Q 4Q

20011Q 2Q 3Q 4Q

20021Q 2Q 3Q 4Q

20031Q 2Q 3Q 4Q

E1Engineering

E2 E3 E4 E5 E6 E7 E8 E9

S1Science

S2 S3

First Lock Full Lock all IFO's

10-17 10-18 10-19 10-20strain noise density @ 200 Hz [Hz-1/2] 10-21

Runs

10-22

E10

Page 32: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 32LIGO-G030009-01-W

And despite a few difficulties, science runs started in 2002…

Page 33: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 33LIGO-G030009-01-W

Page 34: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 34LIGO-G030009-01-W

LIGO Science Run S1

17 days in Aug-Sep 2002 3 LIGO interferometers in coincidence with GEO600

and ~2 days with TAMA300

“Setting upper limits on the strength of periodic gravitational waves using the first science data from the GEO600 and LIGO detectors”Phys. Rev. D 69, 082004 (2004)

“First upper limits from LIGO on gravitational wave bursts”Phys. Rev. D 69, 102001 (2004)

“Analysis of LIGO data for gravitational waves from binary neutron stars” Phys. Rev. D 69, 122001 (2004)

“Analysis of first LIGO science data for stochastic gravitational waves” Phys. Rev. D 69, 122004 (2004)

Page 35: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 35LIGO-G030009-01-W

Binary Neutron Stars:S1 Range

Image: R. Powell

Page 36: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 36LIGO-G030009-01-W

LIGO Science Run S2

Feb 14 – Apr 14, 2003 3 LIGO interferometers in coincidence with

TAMA300; GEO600 not available for science running

A Search for Gravitational Waves Associated with the Gamma Ray Burst GRB030329 Using the LIGO Detectors

Limits on gravitational wave emission from selected pulsars using LIGO data

Page 37: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 37LIGO-G030009-01-W

Binary Neutron Stars:Initial LIGO Target Range

Image: R. Powell

S2 Range

Page 38: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 38LIGO-G030009-01-W

What’s next? Advanced LIGO…Major technological differences between LIGO and Advanced LIGO

Initial Interferometers

Advanced Interferometers

Open up wider band

ReshapeNoise

Quadruple pendulum

Sapphire optics

Silica suspension fibers

Advanced interferometry

Signal recycling

Active vibration isolation systems

High power laser (180W)

40kg

Page 39: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 39LIGO-G030009-01-W

Binary Neutron Stars:AdLIGO Range

Image: R. Powell

LIGO Range

Page 40: LIGO-G030009-01-W "Colliding Black Holes" Credit: National Center for Supercomputing Applications (NCSA) Intro to LIGO Fred Raab, LIGO Hanford Observatory

LIGO: Portal to Spacetime 40LIGO-G030009-01-W

A Sampling of PhD Theses on LIGO

Giaime – Signal Analysis & Control of Power-Recycled Fabry-Perot-Michelson Interferometer

Regehr – Signal Analysis & Control of Power-Recycled Fabry-Perot-Michelson Interferometer

Gillespie – Thermal Noise in Suspended Mirrors Bochner – Optical Modeling of LIGO Malvalvala – Angular Control by Wave-Front Sensing Lyons – Noise Processes in a Recombined Suspended Mirror

Interferometer Evans – Automated Lock Acquisition for LIGO Adhikari – Noise & Sensitivity for Initial LIGO Sylvestre – Detection of GW Bursts by Cluster Analysis