Advanced LIGO and
the 2nd generation of gravitational waves observatories
Giacomo Ciani for the
LIGO Scientific Collaboration
LIGO-G1101293
• GW and laser interferometers
• The first generation of detectors
• Towards advanced detectors
• Advanced detectors network
• What’s next?
• Summary
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Overview
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• Who says GWs exist? – Predicted by General Relativity
– Hulse-Taylor: indirect evidence by binary pulsar spin-down (Nobel Prize 1993)
• What are gravitational waves? – Ripple in space-time travelling at the speed
of light
• Who creates GWs? – Mass distributions changing in a non-
spherically symmetric way (e.g. binary systems)
• What is their effect? – Relative change in lengths orthogonal to
propagation direction
– The effect is VERY small: typical size
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
FAQs on gravitational waves
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Relic radiation Cosmic Strings
Supermassive BH Binaries
BH and NS Binaries
Binaries coalescences
Extreme Mass Ratio Inspirals
A whole orchestra on the stage
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
10-9 Hz 10-4 Hz 100 Hz 103 Hz 10-16 Hz
Supernovae
Spinning NS
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And a microphone for everyone
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
10-9 Hz 10-4 Hz 100 Hz 103 Hz
Relic radiation Cosmic Strings
Supermassive BH Binaries
BH and NS Binaries
Binaries coalescences
Extreme Mass Ratio Inspirals
Supernovae
Spinning NS
10-16 Hz
Inflation Probe Pulsar timing Space detectors Ground interferometers
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DL
PP
D
• Inherently differential
• Broad band
• Long baseline
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Laser interferometers
Laser
“+” polarized GW propagating
orthogonal to the screen
Phase: f = 4p (Lx – Ly) /l ~ DL Power: PPD = PBS sin2f
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Initial detectors era: Initial LIGO
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Laser
Laser: 10W - 1064nm
Input mode cleaner: stabilizes frequency
and clean laser mode
Arm cavities: Faby-Perrot cavities
store light to effectively increase
length
RF Heterodyne Readout
Power recycling mirror: reflects back light coming
from the beam splitter, increasing power in the
arm cavities
Input Test
Mass
End Test
Mass
4 km
4 km
10kW 1
0kW
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iLIGO strain sensitivity
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Now Inauguration First Lock Full Lock all IFO
4K strain noise
@150 Hz [Hz-1/2]
3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
1999 2000 2001 2002 2003 2004 2005 2006
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2007
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2008
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Design Sensitivity
10-17 10-18 10-20 10-21 10-22 3x10-23
Enhanced LIGO
Seismic noise (displacement): mechanical vibration of the ground transmitted to the mirror through the pendulum chain
Suspension thermal (displacement): thermal agitation induce noise in mirror motion
Shot noise (detection): random arrival of photons creates noise at high frequencies
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PLUS:
• Better input optic to handle higher power
• Upgraded Thermal Compensation System to correct thermal distortions and lensing
• In-vacuum readout components
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
An intermediate step: Enhanced LIGO
Laser
4 km
4 km Laser:
10W - 1064nm
Output mode cleaner: Reject junk light to clean signal on photodetector
DC Homodyne Readout
10kW 1
0kW
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PLUS:
• Better input optic to handle higher power
• Upgraded Thermal Compensation System to correct thermal distortions and lensing
• In-vacuum readout components
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
An intermediate step: Enhanced LIGO
Laser
4 km
4 km Laser:
10W - 1064nm
Output mode cleaner: Reject junk light to clean signal on photodetector
DC Homodyne Readout
10kW 1
0kW
102
103
10-23
10-22
Frequency [Hz]
h(f
) [H
z-1
/2]
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All the actors on the scene
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
TAMA300
LIGO Hanford (2 IFOs)
LIGO Livingston
VIRGO
GEO600
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• More than 60 LSC-authored papers on S1..S5: – “Implications for the Origin of GRB 070201 from LIGO Observations”,
Astrophys. J. 681 (2008) 1419 – “Beating the spin-down limit on gravitational wave emission from the
Crab pulsar”, Astrophys. J. Lett. 683 (2008) 45 – “An upper limit on the stochastic gravitational-wave background of
cosmological origin”, Nature 460 (2009) 990 – …and many more…
• Many LSC-authored articles on S6, published or to be published soon:
– “A gravitational wave observatory operating beyond the quantum shot-noise limit”, Nat Phys online: doi:10.1038/nphys2083
– “All-sky search for periodic gravitational waves in the full S5 LIGO data”, arXiv:1110.0208
• Created expertise in design, commissioning and operation of large scale
interferometric detectors
• Created a strong international community – The LIGO and VIRGO scientific collaborations work now in full synergy
(data analyzed jointly since 2007)
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Initial/Enhanced detectors results
First Science Data
S1 S4 LIGO Science
Runs
S2
S6 ends 10/20/2010
S3 S5 S6
1 year of Coincidence Data 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
1999 2000 2001 2002 2003 2004 2005 2006
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2007
1 2 3 4
2008
1 2 3 4
2009
1 2 3 4
2010
1 2 3 4
2011
Enhanced LIGO
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• More than 60 LSC-authored papers on S1..S5: – “Implications for the Origin of GRB 070201 from LIGO Observations”,
Astrophys. J. 681 (2008) 1419 – “Beating the spin-down limit on gravitational wave emission from the
Crab pulsar”, Astrophys. J. Lett. 683 (2008) 45 – “An upper limit on the stochastic gravitational-wave background of
cosmological origin”, Nature 460 (2009) 990 – …and many more…
• Many LSC-authored articles on S6, published or to be published soon:
– “A gravitational wave observatory operating beyond the quantum shot-noise limit”, Nat Phys online: doi:10.1038/nphys2083
– “All-sky search for periodic gravitational waves in the full S5 LIGO data”, arXiv:1110.0208
• Created expertise in design, commissioning and operation of large scale
interferometric detectors
• Created a strong international community – The LIGO and VIRGO scientific collaborations work now in full synergy
(data analyzed jointly since 2007)
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Initial/Enhanced detectors results
First Science Data
S1 S4 LIGO Science
Runs
S2
S6 ends 10/20/2010
S3 S5 S6
1 year of Coincidence Data 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
1999 2000 2001 2002 2003 2004 2005 2006
1 2 3 4
2007
1 2 3 4
2008
1 2 3 4
2009
1 2 3 4
2010
1 2 3 4
2011
Enhanced LIGO
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Advanced detectors: the big step
• Re-use existing facilities • 10 times better in strain (15->150 Mpc fro NS-NS)
– 1000x improvement in observable volume (= rate)
• Improvement at low frequency (from 40 to 10 Hz) – Increase type (higher masses) and number of sources – Increase signal “in-band” time
• Limited by fundamental noise: quantum, thermal • Tunable
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
10-24
10-23
10-22
10-21
10-20
10-19
Str
ain
(1
/ Hz)
101
2 3 4 5 6 7 8 9
102
2 3 4 5 6 7 8 9
103
2 3 4 5 6 7 8 9
104
Frequency (Hz)
Hanford 4 km S6
Livingston 4 km S6
AdvLIGO, No Signal Recycling (early operation)
AdvLIGO, Zero Detuning (Low Power)
AdvLIGO, ZeroDetuning (High Power)
AdvLIGO, NS-NS optiimized AdvLIGO, High Frequency Detuning
Initial
LIGO
Advanced
LIGO
Abadie, et al. “Predictions for the Rates of Compact Binary Coalescences Observable by Ground-based Gravitational-wave Detectors” CQG 27 173001 (2010), arXiv:1003.2480
Neutron Star (NS) = 1.4 M
, Black Hole (BH) = 10 M
Routine detection not certain, but plausible!
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Advanced LIGO: key improvements
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Input Laser Mirrors Topology Readout Sensitivity Seismic isolation
iLIGO 10W
(10 kW arm) 10 kg
Power-Recycled Fabry-Perot
RF etherodyne
3 10-23 Hz-1/2 Single pendulum (LF cutoff ~40 Hz)
aLIGO 180W
(>700 kW arm) 40 kg
Dual-Recycled Fabry-Perot
DC homodyne
5 10-24 Hz-1/2 broadband (tunable)
Quadruple pendulum (LF cutoff ~10 Hz)
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Advanced LIGO: key improvements
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Input Laser Mirrors Topology Readout Sensitivity Seismic isolation
iLIGO 10W
(10 kW arm) 10 kg
Power-Recycled Fabry-Perot
RF etherodyne
3 10-23 Hz-1/2 Single pendulum (LF cutoff ~40 Hz)
aLIGO 180W
(>700 kW arm) 40 kg
Dual-Recycled Fabry-Perot
DC homodyne
5 10-24 Hz-1/2 broadband (tunable)
Quadruple pendulum (LF cutoff ~10 Hz)
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Advanced LIGO: key improvements
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Input Laser Mirrors Topology Readout Sensitivity Seismic isolation
iLIGO 10W
(10 kW arm) 10 kg
Power-Recycled Fabry-Perot
RF etherodyne
3 10-23 Hz-1/2 Single pendulum (LF cutoff ~40 Hz)
aLIGO 180W
(>700 kW arm) 40 kg
Dual-Recycled Fabry-Perot
DC homodyne
5 10-24 Hz-1/2 broadband (tunable)
Quadruple pendulum (LF cutoff ~10 Hz)
New Test Masses: • 40 kg • 38 cm in diameter • Polishing: 0.15 nm rms • Coating absorption: 0.5 ppm
-1 nm
1 nm
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Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Advanced LIGO: key improvements Input Laser Mirrors Topology Readout Sensitivity Seismic isolation
iLIGO 10W
(10 kW arm) 10 kg
Power-Recycled Fabry-Perot
RF etherodyne
3 10-23 Hz-1/2 Single pendulum (LF cutoff ~40 Hz)
aLIGO 180W
(>700 kW arm) 40 kg
Dual-Recycled Fabry-Perot
DC homodyne
5 10-24 Hz-1/2 broadband (tunable)
Quadruple pendulum (LF cutoff ~10 Hz)
Signal recycling cavity: Resonant for the sidebands created
by GW signal
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• Two stage active pre-isolation
• 4 stage TM supension with reaction chain
• Last stage: monolitic fused silica
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Advanced LIGO: key improvements Input Laser Mirrors Topology Readout Sensitivity Seismic isolation
iLIGO 10W
(10 kW arm) 10 kg
Power-Recycled Fabry-Perot
RF etherodyne
3 10-23 Hz-1/2 Single pendulum (LF cutoff ~40 Hz)
aLIGO 180W
(>700 kW arm) 40 kg
Dual-Recycled Fabry-Perot
DC homodyne
5 10-24 Hz-1/2 broadband (tunable)
Quadruple pendulum (LF cutoff ~10 Hz)
ISI: Internal Seismic Isolator
HEPI: Hydraulic External Pre-Isolator
HAM Chambers isolation
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Advanced LIGO: key improvements
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Input Laser Mirrors Topology Readout Sensitivity Seismic isolation
iLIGO 10W
(10 kW arm) 10 kg
Power-Recycled Fabry-Perot
RF etherodyne
3 10-23 Hz-1/2 Single pendulum (LF cutoff ~40 Hz)
aLIGO 180W
(>700 kW arm) 40 kg
Dual-Recycled Fabry-Perot
DC homodyne
5 10-24 Hz-1/2 broadband (tunable)
Quadruple pendulum (LF cutoff ~10 Hz)
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Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Advanced LIGO: key improvements Input Laser Mirrors Topology Readout Sensitivity Seismic isolation
iLIGO 10W
(10 kW arm) 10 kg
Power-Recycled Fabry-Perot
RF etherodyne
3 10-23 Hz-1/2 Single pendulum (LF cutoff ~40 Hz)
aLIGO 180W
(>700 kW arm) 40 kg
Dual-Recycled Fabry-Perot
DC homodyne
5 10-24 Hz-1/2 broadband (tunable)
Quadruple pendulum (LF cutoff ~10 Hz)
Initia
l
LIGO
Seismic cu
toff
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• About 60% done: – Removal of initial LIGO complete for two interferometers – Almost all Advanced LIGO equipment contracted for production – A lot of equipment – almost all Seismic and Suspension parts – made; DAQ installed and running;
2km test mass chambers moved 4km – PSL installed at LLO and one of the LHO IFOs
• Some delays: fabrication difficulties (vacuum equipment, suspension parts, optics), puzzles in
testing, assembly, chamber cleaning. Mostly overcome. • Despite delays, still 5 months ahead of NSF schedule
• Integrate One Arm Test to occur March, 2012:
– A complete, single arm assembled and locked as a stand-alone cavity – Will test main isolation hardware and locking scheme
• Current plan to have interferometers accepted (2 hour lock) July 2014
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
To road to Advanced LIGO
3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
2012 2013 2014 2015 2016 2017 2018 2006
1 2 3 4
2007
1 2 3 4
2008
1 2 3 4
2009
1 2 3 4
2010
1 2 3 4
2011
aLIGO
project starts
Observatories
hand-off to aLIGO
Integrated
One Arm Test
1st IFO
accepted
2nd and 3rd IFOs
accepted
GW Astronomy begins!
Right now
>60% complete
Dark Era S6 S5 eLIGO inst.
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• Located in Italy • Operated by European
Consortium • 3 km arm length • Similar design to aLIGO:
– limited by fundamental noise – unique SuperAttenuator
design
• Expected online in 2015 (same as aLIGO)
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Other detectors: AdVIRGO credits:
Giovanni LOSURDO & Jean-Yves VINET / VIRGO
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• Located in Kamyoka mines, Japan
• 3 km arm length
• Pioneering in next generation technologies: – Underground
– Cryogenics
– Alternative materials
• Two phases: full sensitivity expected in 2017
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Other detectors: LCGT
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• Locate in Hannover, Germany • Part of the LIGO collaboration • 600 m baseline • Limited sensitivity as low frequencies • Pioneers advanced techniques:
– Squeezing – Signal recycling – More…
• The only listener until 2015!
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Other detectors: GEO HF
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• Proposal: move one of the Hanford detectors to Australia – ACIGA to provide:
• Infrastructures (including vacuum system)
• Staff for routine operation
– LIGO to provide: • Detector components
• Assistance for installation and commissioning
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
The case of LIGO Australia
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• Increased sky coverage
• Greatly enhanced sky localization
• Increase duty cycle
• Decoupling of local noise for 3rd LIGO detector
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
The case of LIGO Australia
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Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
The case of LIGO Australia
• LIGO Australia didn’t happen due to budget constraints in Australia
• A similar proposal for India is now under investigation: – NFS reviewed the scientific case: found compelling
– Deadline for India commitment: March 2012
• Scientific advantage would be comparable – Even better if we include LCGT
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All the actors on the scene
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
aLIGO Hanford 2015
aLIGO Livingston 2015
AdVIRGO 2015
GEO600 Now!
LCGT 2017
Increased detection confidence (coincidence runs)
Reduced downtime
Enhanced sky coverage Better and faster source localization
More reliable source parameters estimation
LIGO India 2020?
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• Go underground (LCGT) – Easy… but expensive!
• Band- specific detectors – Less easy… still expensive!
• Go cryogenic (LCGT) – New material – New lasers – Cooling… quietly!
• Fight coating thermal noise: – Low-loss (crystalline?)
coatings – Gratings – Exotic beam profiles
• Beat the Standard Quantum Limit! – Frquency-dependent
squeezing – Ponderomotive squeezing
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
Farther down the road…
See “Einstein gravitational wave Telescope conceptual design study”
https://tds.ego-gw.it/itf/tds/index.php?callContent=2&callCode=8709
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• Squeezing: – Vacuum fluctuations creates noise at the
“dark” port
– Injecting 3 dB of squeezed light (“vacuum”, actually) is equivalent to 2x increase in power
– Demonstrated in GEO (6 dB) and recently in H1 (>2 dB)
• Newtonian noise subtraction – Noise due to local gravitational field
variations might already show up in aLIGO
– Can be subtracted by accurate modeling and monitoring of sources
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
… or just around the corner
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• Initial generation of interferometers: – No detection
– Many significant scientific results
– Training bench for the advanced detectors
– Built a strong worldwide GW community
• Advanced detector: – Construction well under way
– aLIGO and adVirgo expected online 2015
– Others to join the network soon after
– “GW astronomy era” at hand
• In the meanwhile, plans are underway for the development of the next generation of detector
Dec 19th, 2011 – CGC Conference in Fort Lauderdale Giacomo Ciani for the LSC LIGO-G1101293
All in one slide
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