Groundbased Gravitational Wave

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• Ground-based Gravitational Wave
• Detectors A Status Report
• David Reitze
• Physics Department
• University of Florida

LIGO Hanford
Virgo
LIGO Livingston
LCGT (proposed)
AIGO (proposed)
GEO 600
LIGO G080283-00-Z
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Motivation for the global network

• Better detection confidence through redundancy
• Coverage Ability to be on the air with one or
  more detectors
• Source location Ability to triangulate and more
  accurately pinpoint source locations in the sky
• Polarization array of oriented detectors is
  sensitive to two polarizations
• Coherent analysis optimal waveform and
  coordinate reconstruction, better discrimination

GEO
VIRGO
TAMA
LIGO
AIGO
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Ground-based
Astrophysical targets for ground-based detectors

• Bursts
• galactic asymmetric core collapse supernovae
• cosmic strings
• ??? (the Get lucky category)

• Continuous Sources
• Spinning neutron stars
• probe crustal deformations, quarki-ness

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• LIGO

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Initial LIGO

• Two observatories, three interferometers
• LIGO Hanford Observatory
• 4 km, 2 km interferometers
• LIGO Livingston Observatory
• 4 km interferometer
• Topology Power Recycled Michelson Interferometer
  with Fabry-Perot Arm Cavities

Y - End
Test
Mass
10 kW
Y - Input
Test
X - Input
Mass
Test
5 W
BS
Mass
NdYAG
X - End
Test
250 W
10 kW
Laser
Mass
Photodiode
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It works.
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LIGO Science Runs

• Five Science Runs To Date
• S1 August 23 - September 9, 2002 (17 days)
• S2 February 14 April 14, 2003 (59 days)
• S3 October 31, 2003 January 9, 2004 (70 days)
• S4 February 22 March 23, 2005 (30 days)
• S5 November 4, 2005 September 31, 2007
• gt 365 days of triple coincidence, 400 days of
  double coincidence
• Duty cycle 78 for the Hanford 4k, 79 for the
  Hanford 2k and 66 for Livingston 4k
• LSC-Virgo started data-sharing on May 18, 2007
• Virgo VSR1 May 18, 2007 Oct 1, 2007
• gt75 days of 3-site coincidences with LIGO, 95
  days of 2-site coincidences
• Duty cycle 81 for Virgo

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LIGO Science Collaboration Observational Papers

• 31 papers posted/submitted
• 26 since 2005
• ArXiv links http//www.lsc-group.phys.uwm.edu/ppco
  mm/Papers.html

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Beating the spin-down limit on gravitational wave
emission from the Crab pulsar

• spin frequency nEM 29.8 Hz
• ? ngw 2 nEM 59.56 Hz
• spindown mechanisms
• asymmetric particle ejection, magnetic dipole
  radiation, GW emission?
• Data from Nov 2005 Aug 23, 2006
• time and frequency domain searches
• S5 upper limit
• time-domain, restricted priors on orientation and
  polarization
• h lt 2.67 x 10-25 ? 5.3x below
• the spindown limit
• lt 3.6 of Crab energy is radiated in GWs
• S5 ellipticity
• e lt 1.44 x 10-4

lthttp//arxiv.org/abs/0805.4758gt
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Implications for the Origin of GRB 070201 from
LIGO Observations

• GRB 070201
• An intense, short duration, hard spectrum g-ray
  burst
• Error box coincident with outer spiral arm of M31
• Progenitor? Binary merger or SGR.
• Matched filter search for inspiral waveforms
• No gravitational wave detected
• Binary merger in M31 scenario excluded at gt99
  level
• Exclusion of merger at larger distances
• Excess power burst search
• No gravitational wave detected
• Cannot exclude a SGR in M31 distance
• Upper limit 8x1050 ergs (4x10-4 M?c2) (emitted
  within 100 ms for isotropic emission of energy in
  GW at M31 distance)

lthttp//arxiv.org/abs/0711.1163gt
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Astrowatch program

• Major detectors all undergoing upgrades from late
  2007 through early 2009
• Astrowatch program initiated to keep an eye on
  the sky
• no heavy duty analysis will look at data for
  exceptional externally triggered events
• Participating detectors
• LIGO Hanford 2 km
• Run by LSC graduate students!!!
• GEO600
• Virgo
• AURIGA bar detector
• Hanford 2 km stats
• In science mode 34 of time
• 6-7.5 Mpc BNS range
• Archiving 12-20 hours data per day
• GEO600 stats
• 84.4 science mode

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Enhanced LIGO

• Sensitivity goal gt 2X increase over initial LIGO
• New readout scheme
• DC (homodyne)
• Suspended output mode cleaner seismic isolation
• Active steering and jitter suppression
• In-vacuum detection diodes
• Higher laser power ? 35 W
• New Input Optics components to handle the power
• Upgraded thermal compensation system (TCS) to
  compensate for absorbed power
• New magnets, better electronics, a few other
  fixes
• Upgrades test Advanced LIGO technologies!!!

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E-LIGO Progress

• Hardware 95 complete
• Installation 85 complete
• Livingston
• New readout beamline installed
• OMC, HAM ISI installed
• In-vac Input Optics upgraded
• SiO2 earthquake stops on ITMS
• Hanford
• New readout installed
• ISI installed
• 35 W laser installed
• all Input Optics upgraded
• ETM NeFeB magnets replaced with SmCo
• Commissioning proceeding at both sites
• Current progress calls for S6 to begin in early
  2009

Seismic isolation
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E-LIGO in pictures
OMC Suspension
E-LIGO/AdvLIGO Faraday Isolator
HAM ISI Installation
HAM ISI Active Seismic System
OMC Lit-up
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E-LIGO commissioning progress

• LLO DC readout operational!
• Scaled power operation comparable to S5
  sensitivity at equivalent powers
• Caveat 1 OMC transmission is 85
• Caveat 2 excessive dark noise in detection
  diode
• Lots of measurements of noise couplings
• LHO 35 W laser running
• Intensity stabilization loop being tuned

S5
E-LIGO
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Advanced LIGO

• Began in 1999 as an LSC concept paper
• Major RD from 1999-2006
• In anticipation of positive funding outcome, many
  subsystems through preliminary design phase by
  2006
• Final baseline review by NSF in November 2007
• Very positive reviews
• Advanced LIGO Project officially began on April
  1, 2008

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Advanced LIGO overview

• What is Advanced?

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Advanced LIGO subsystems
Mirror Suspensions
Seismic isolation
Mirrors
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• GEO600

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GEO 600

• One observatory, one interferometer
• Located near Hannover, Germany
• Folded arms, 1.2 km in length
• Topology power and signal recycled Michelson
• Operated as one of the four LSC detectors and has
  been taking data since 2002.
• Also a think-tank and test-bed for the technical
  improvements for future gravitational wave
  detectors
• Signal recycling
• Multi-stage pendulum suspension
• Squeezing
• and a very reliable detector

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GEO HF

• GEO High Frequency the next phase in GEO600
  evolution
• Goals
• Improve sensitivity at high frequency to be
  comparable to LIGO, Virgo
• Engineer and demonstrate stable and long term
  squeezing on a large scale detector
• Prototype other advanced techniques
• Nice progress (during Astrowatch!)
• Demonstration of improved sensitivity DC readout

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GEO HF - Squeezed light

• By injecting squeezed vacuum into the
  asymmetric port of an interferometer, it is
  possible to reduce amplitude or phase
  fluctuations below the Heisenberg limit
• beat shot noise
• Laboratory record to date is 10 dB squeezing
• More sensitivity for less photons!
• Easy way to alleviate thermal effects in
  interferometers

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• VIRGO

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Initial Virgo

• One observatory, one interferometer
• Virgo Observatory in Casina, Italy
• 3 km interferometer
• Topology Power Recycled Michelson Interferometer
  with Fabry-Perot Arm Cavities
• Low frequency seismic
• attenuation (4 Hz)

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Virgo at VSR 1
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Virgo Commissioning Progress

• Improvements on every front!
• Reduced actuation noise
• New coil drivers with multi-low noise sections
  introduced
• Reduced eddy current damping
• Suspected increase in thermal noise due to eddy
  current dissipation of the mirror magnets in the
  reference masses
• Solution replace all the mirror magnets with 5.5
  times less intense SmCb magnets
• Improved longitudinal control
• New sensing scheme for the central interferometer
  control Optimization of control filters
  improvement of noise subtraction techniques
• Improved angular control
• Better beams and optics
• Improved control filters and new galvos
• Improved suspension control
• Reduced actuation noise
• Reduced beam jitter before input mode cleaner
• Reduced scattered light
• Reduced magnetic coupling
• Higher power operation
• TCS system, based on a CO2 laser ring for each
  input mirror

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Virgo Sensitivity Gains
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Post VSR1
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Virgo NE tower incident

• On May 9, at 1848 UTC a viewport imploded during
  the pump down of the NE end station
• No one injured
• Gate valves were closed NE tower isolated
• Damage confined to the NE tower
• Mirror, suspension, baffles
• Detailed investigation and forensic effort
  underway to understand cause of the accident
• Some delay in commissioning, but schedule
  workarounds are in place
• Laser upgrade, other commissioning activities
• Likely that a new mirror will be coated and ready
  for installation in August

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Virgo

• High power laser and compliant optics integration
• Control and DAQ Electronics
• Environmental noise mitigation
• Control electronics
• Photodiodes under vacuum
• Possibly Monolithic suspensions and new mirrors

Vacuum Photodiodes
Test monolithic suspension
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Advanced Virgo
BNS range 121 Mpc BBH range 856 Mpc 1 kHz
sens. 6 10-24/vHz

• Sensitivity goal 10x better than initial Virgo
• Timeline comparable to AdvLIGO
• Fall 2008 first AdV review

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• TAMA/CLIO/LCGT

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Progress on TAMA300

• Operated until 2004 as a GW detector
• In 200,1TAMA DT6 achieved 1000 hours of science
  data with worlds best sensitivity at the time
• Since 2004, working on improving low frequency
  performance
• New TAMA SAS (seismic isolation system) installed
  
• Improved controls
• Alignment
• Differential Michelson feedforward
• Laser intensity noise

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CLIO

• Underground testbed for LCGT
• Located in Kamioke mine
• 100x suppression of low frequency ground motion
• 100 m Fabry-Perot arm cavities
• 0.5 W laser
• First medium scale interferometer with
  cryogenically cooled mirrors
• Sapphire substrates
• 6 vibration isolation stages
• 3 stages _at_ 300L
• 3 stages _at_ 10K
• Achieved 13K cooling on all mirrors

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Large Cryogenic Gravitational-wave Telescope
(LCGT)

• Cryogenic underground km scale!
• 100 Mpc planned coverage
• Challenges
• Underground low frequency operation in the
  presence of cryogenic refrigerators
• Suspension point interferometry
• Thermal effects due to high laser power
• Key technologies demonstrated in CLIO
• International collaboration welcome!

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LCGT Design
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LCGT Design Sensitivity
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• AIGO/Gingin

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The case for a southern hemisphere detector
ANU
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AIGO

• A comparably sensitive detector in Australia
  would bring increased angular sensitivity

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AIGO Roadmap

• National Advisory Committee formed in 2007
• NAC Recommendations
• Window of opportunity for commencing a
  large-scale AIGO detector is now ? must be
  operational during AdvLIGO, AdvVirgo eras
• Development of AIGO Roadmap
• Roadmap coordinator hired
• AIGO Roadmap
• Formulated early 2008
• AIGO should follow the AdvLIGO design
• Possible variation in suspension and seismic
• isolation system
• Locate at Gingin
• International partnership highly desirable
• Aim for operation in 2017
• 2-3 year lag behind AdvLIGO

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• The Einstein Telescope

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The Einstein Telescope

• European FP7 design study for a 3rd generation
  instrument
• Second generation observatory
• Motivations
• Physics goals beyond that of advanced detectors
• Test GR in strong field regime
• High SNR detections for waveform reconstruction
• End state of gravitational collapse
• Population census of BNSs in high Z universe
• Now is the time to begin to think about a
  ground-based 3rd generation detector

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ET Target Sensitivity
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ET design study topics

• Triangular topology
• All-sky sensitivity
• Polarization analysis
• Improved Sensitivity
• Thermal Noise
• Longer arms (10 km)
• Cryogenic mirrors
• Consider new materials, wavelengths (eg. Silicon,
  1550 nm)
• Non-gaussian optics
• Novel coatings
• Seismic Noise
• Underground
• Anthropogenic noise
• Newtonian noise?
• Shot noise
• High laser power (3 MW!)
• Co-located detectors
• Squeezing

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The Bar Detectors
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IGEC- International Gravitation Event
Collaboration

• International network of bar detectors
• In operation since mid 90s
• Improvements in bandwidth and sensitivity ? IGEC 2

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• AURIGA
• currently actively taking data
• and doing science
• A Joint Search for Gravitational Wave Bursts
  with AURIGA and LIGO,
• Class. Quantum Grav. 25 (2008) 095004

will be phased out as a GW detector as soon as
enhanced LIGO/Virgo will be on the air
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The Future Global Network of Gravitational Wave
Detectors
Advanced LIGO Washington, USA
LCGT Japan
ET (Europe)
AIGO Australia
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Conclusions

• Terrestrial gravitational wave detectors
• Progress on all fronts in all projects
• The plan for the near and longer term future are
  established and moving forward
• We will all work as a network
• The big detectors are producing interesting
  science
• In the absence of a detection
• These are exciting times to be working in the
  field of gravitational waves.

Thanks to David Blair, Francesco Fidecaro, Seiji
Kawamura, Kazuaki Kuroda, Harald Lueck, Giovanni
Losurdo, Michele Punturo, Gabriele Vajente, and
Sam Waldman for providing much of the material
for this talk!
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The AdvLIGO Project
Funding Start
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