IGEC2 COLLABORATION: A NETWORK OF RESONANT BAR DETECTORS SEARCHING FOR GRAVITATIONAL WAVES
Searching for gravitational waves with lasers
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Transcript of Searching for gravitational waves with lasers
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Searching for gravitational waves with lasers
Rick SavageCaltech
LIGO Hanford Observatory - Richland, WA
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Sept 1974 - transferred to UCLA in Physics Jan 1975 - started working for F. Chen and N. Luhmann
as undergraduate lab assistant (with Doug Cook) 1976 to1986 - plasma diagnostics with N. Luhmann, T.
Peebles, H. Fetterman, et al. 1986 to 1992 - graduate school in EE at UCLA with
Chan Josh, Warren Mori, Ken Marsh, Chris Clayton, et al.» Masters thesis – Degenerate four-wave mixing in heated CO2 gas» PhD thesis – Frequency upshifting of electromagnetic radiation via an
underdense relativistic ionization front 1992 to present - LIGO project at Caltech until 1997
then LIGO Hanford Observatory in Richland, WA
LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009
Black holes and time warps
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LIGO: Laser Interferometer Gravitational-wave Observatory
3002 km(L/c = 10 ms)
Caltech
MIT
• Managed and operated by Caltech & MIT with funding from NSF
• Goal: Direct observation ofgravitational waves
•Open an new observationalwindow on the Universe
Livingston, LA
Hanford, WA
LIGO-G0901004
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LIGO Scientific Collaboration
UCLA Symposium F2C@80 Nov. 2009LIGO-G0901004
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General relativity – gravitational waves
UCLA Symposium F2C@80 Nov. 2009
Laser Interferometer
GW: oscillating quadrupolar strain in spacetime
“Matter tells spacetime how to curve.Spacetime tell matter how to move.”
J. A Wheeler
Albert Einstein1916
LIGO-G0901004
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Potential sources
Credit: AEI, CCT, LSU
Coalescing Binary Systems• Neutron stars,
low mass black holes, and NS/BS systems
Credit: Chandra X-ray Observatory
‘Bursts’ galactic asymmetric core collapse supernovae
cosmic strings
???
NASA/WMAP Science Team
Cosmic GW background stochastic, incoherent background
Casey Reed, Penn State
Continuous Sources Spinning neutron stars
probe crustal deformations
UCLA Symposium F2C@80 Nov. 2009LIGO-G0901004
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Capturing the waveform
LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009
Sketch:Kip Thorne
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Detection of gravitational waves
UCLA Symposium F2C@80 Nov. 2009
Michelson interferometer- differential length change sensor
LIGO-G0901004
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Ligo detectors
UCLA Symposium F2C@80 Nov. 2009
Laser
4 km-long Fabry-Perotarm cavity
recyclingmirror test masses
beam splitter
Power RecycledMichelsonInterferometerwith Fabry-PerotArm Cavities
signal
LIGO-G0901004
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Beam tubes and chambers
LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009
Beam tubes:• 1.2 m diameter• LN2 pumps at ends• P < 1e-09 torr• dominated by H2
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Isolated environment for test masses
LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009
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Suspended test masses
LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009
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NS-NS binary inspiral range ~ 15 Mpc (S/N = 8)
Initial LIGO displacement sensitivity
UCLA Symposium F2C@80 Nov. 2009LIGO-G0901004
Antenna patterns
+pol
Gpol
avg
S5 science runNov. `05toOct `07
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No detections (so far) - data still being analyzed Astrophysical results – upper limits
“If LIGO didn’t detect it, then it can’t be bigger than …”» CRAB pulsar – “no more than 4 percent
of the energy loss of the pulsar is caused by the emission of gravitational waves.” (ApJL 683, L45)
» Gamma ray burst GRB 070201 – LIGO “results give an independent wayto reject hypothesis of a compact binaryprogenitor in M31”(ApJ 2008, 681, 1419)
» Upper limit on the stochastic gravitational wave background(http://www.nature.com/nature/journal/v460/n7258/pdf/nature08278.pdf)
LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009
Scientific results of S5 run
Credits for X-ray Image: NASA/CXC/ASU/J. Hester et al.Credits for Optical Image: NASA/HST/ASU/J. Hester et al.
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What’s next? Advanced Ligo.
Quantum noise limited interferometer
Factor of 10 increase in sensitivity
Factor of 1000 increase in event rate
LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009
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Laser source: 10 W to 200 W
LIGO-G0901004
Diode-pumpedYAG lasers
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Vibration isolation: passive to active
LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009
• Geophones and accelerometers on payload• Active feedback control – 6 deg. of freedom
• Masses anddamped springs
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Test mass suspensions
LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009
• Quadruple pendulumwith reaction masses
• 40 kg test masses
• Single pendulum
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Time warp – 1763 Boelter Hall
LIGO-G0901004
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UCLA Symposium F2C@80 Nov. 2009
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To Frank ……. thank you.
LIGO-G0901004