Gravitational Waves:Current and future experiments

Kazuaki Kuroda

ICRR, The University of Tokyo

TAUP2011 @ Munich5-9, September

Related talks in parallel session yesterday

• Well-balanced introductory talk by Laura Cadonati (U Mass)

• Noise and signal by Giovanni Andrea Prodi (U Trento)

• LCGT status by Shinji Miyoki (ICRR, UT)

• Starving field of GW by Bruce Allen (MPI, Hannover)

• GW from rotating star by Andrzej Krolak (Inst. Math, Polish Academy of Science)

• ET by Harald Lueck (MPI, AEI)

• Bar detector response to cosmic particle by Francesco Ronga (INFN)

• A laser gryo by Angela Virgilio (INFN-Pisa)

• Gravity waves are produced dynamic motion of massive terrestial objects. Here consider the radiation by simple rotating equal masses

• Radiation formula of EM Luminosity = (2/3c3) e2a2

• Radiation from Mass dipole moment = 0

• Radiation of mass quadrupole moment is the lowest term of gravity wave

• Gravity wave luminosity = (G/5c5)( I )2

I = Ijk Ijk , Ijk= ΣmA(xAjxAk-1/3δjkrA2)

Ijk: the reduced quadrupole moment

Introduction: Generation of Gravity wave

Introductory talk by Laura

& spinning star by A Krolak

Introduction: Target GW Sources

• PSR B1913+16

• PSR B1534+21

• PSR J1141-6545

• PSR J0737-3039

• PSR J1906+0746

Existing neutron star binaries in our Galaxy

1. Coalescence of neutron star binaries2. Coalescence of black hole binaries3. Core collapse of massive stars4. ･････

msec

chirp signalcoalescence

quasi-modeoscillation

-300Hz -1kHz

Intro: Detection of gravity wave by resonant antennae

J. Weber started to make practical detector in late of 1960s

Gravity plane wave

0 0 0 00 h11 h12 00 h21 h22 00 0 0 0

hij=

Disk type: Resonant frequency could be changed by making slits

Bar type: Resonant frequency was determinedby the length of the bar

Tidal force of gravity wave causes elastic vibration of eigen mode, which can be detected bysensitive transducer. Thermal noise of vibration is reduced by lowering the temperature.

GR is being tested as in Angela’s talk

61022 1Hz

Peak strain sensitivity

7.21022m Hz

Unprecedented: World Record

Displacement sensitivity

NAUTILUS - INFN Frascati

Vp

Antenna

M

Cd

Rp

Vp

Antenna

M

Cd

Rp

Readout: Resonant capacitive transducer &Dc SQUID amplifierPhys.Rev.Lett. 91:111101, 2003.

106Msunc2Detectable: Galactic burst with

converted in GWs

By the courtesy of Eugenio

Nautilus as acoustic particle detector

Interaction of a particle with a bar: ionization energy lost is converted in thermal heating and therefore pressure wave. The detection mechanism is quite simple, no threshold in β “calorimetric measurement”

Upper limit for nuclearite flux from the Rome GW resonant detectorsPhys.Rev. D47:4770-4773, 1993

Cosmic rays observed by NAUTILUSPhys.Rev.Lett. 84:14-17, 2000.

Detection of high energy cosmic rays with NAUTILUSAstropart.Phys. 30:200-208, 2008.

Nautilus is able to detect energy releases as low as 10-7 eV (10-26 J) by measuring the excitation of the longitudinal mode ofVibration.

Cosmic rays: observedExotic form of matter: observable

Nautilus is equipped with streamer tubesparticle detectors

See presentation file of Francesco

Intro: Detection of gravity wave by Interferometer

z

wave propagation

Photo detector

Mirror XMirror Y

Beam Splitter

Laser

Metric perturbationgij=ηij + hij hij=

0 0 0 00 h11 h12 00 h21 h22 00 0 0 0

Gravity plane wave

Light speed of propagation differs for each arms of Interferometer ΔＬ／Ｌ ≃ ｈ／２

Phase difference at BS is detected by power change of the photodiode

is detected by

Michelson type laser interferometer

Typical amplitude h ~ 10-22

This is also shown by Laura using Fabry-Perot Interferometer

Intro: Noise of Current Interferometers

Anti-vibration system

Seismic noise

Mirror Substrate thermal

Coating thermal

Suspension thermal

Photon counting

Laser pressure

Frequency

sen

sitivity

10 100 1000

Sensitivity limited only by fundamental noise sources

seismic

Suspension thermalMirror thermal

Laser powerBlood sweat and tears in

reducing noise is summarized

in Giovanni’s talk

Current detectors in the World

Adv. LIGO

(under construction）

LCGT (under construction)

LIGO(I) Hanford

LIGO(I) Livingston

GEO HF

Virgo

LIGO-Australia (budget request)

Adv. Virgo (under construction)

ET (planed)

A network of detectors is indispensable to position the source.

TAMA/CLIO

AURIGA

Nautilus

Necessity of more sensitive detectors

• The present detectors such as LIGO (USA), VIRGO (French-Italian), GEO (Germany-England) and TAMA/CLIO (Japan) have sensitivity to catch GW events occurring at most 30Mpc. Since the occurrence rate of the coalescence of BNS is estimated to be 10-5 for matured galaxy per year and there are 0.01 galaxies for 1 cubic Mpc, it takes roughly 300 years to catch one event.

• Advanced detectors are under construction to detect events occurring at around 200Mpc, which makes possible to detect at least a few events of BNS coalescence in a year.

LIGO project and Advanced LIGO

One interferometer

with 4 km Arms,

One with 2 km Arms

One interferometer

with 4 km Arms

Initial LIGO timelineConstruction started in 1994First data-colletction (S1) 2002Design Sensitivity Achieved 2005Enhanced LIGO (S6) 2009-2010

Sensitivity improvement in Initial LIGO (2002-2007)

Efforts of Enhanced LIGO

Increased laser power10 W -> 30-35 WEOMFaraday IsolatorThermal lensingRadiation Pressure

DC readoutOMCDetector in Vacuum

Estimation of Noise

Advanced LIGOScope of Advanced LIGO

Monolithic suspension

TCS performance

New isolation system

Virgo projectItalian-French Collaboration

Construction completedin 2003

Final configuration in 2005Data-taking started in 2006(VSR1) ended in 2007

with LSCVirgo+ (VSR 2, S6) ended

in 2010

Typical features：● Located at Cascina in

Pisa● 3km baseline length● Fabry-Perot Michelson

Interferometer● Ultra-low frequency

isolation system

Low frequency isolation system characterizes the Virgo interferometer

8m

tal

l

Sensitivity Improvement

• High power laser: 25 W (Virgo+) -> 200 W

– Input mode cleaner

– Improved TCS (thermal compensation system)

– Control electronics

• New optics

– Heavier mirror mass

• Monolithic fused silica suspension

• Upgraded seismic isolation system

From Virgo+ to Advanced Virgo

Current design of Advanced Virgo

40 kg test masses

large spot size

dual recycled

DC readout

high powerfiber laser

1) Funded by INFN/CNRS (and contributed by NIKHEF) in Dec 20092) Procurements and parts construction started3) Installation to start at the end of the year4) Acceptance in 2015

GEO600 project

GEO is an observing instrument and a prototype for new technologies'Advanced techniques' of GEO:

Monolothic suspensions (since ~10 years) Electro-static actuatorsSignal recyclingSqueezing (since 2010)

Power Recycling Mirror T=0.09%

Signal Recycling MirrorT=10%

GEO optical Layout

Output modecleaner

End mirrors with Electro-staticactuators

DC readout

Squeezer Installation in May 2010

Squeezing light is introduced from signal port to reduce shot noise. 3.5dB Improvement has been achievedand 4dB more is expected in 2011

22

GEO600 Science Times since 2006

LSC-s5: 421 days, 90% (duty factor in 24/7)

Astrowatch Nov 2007 - July 2009:

522 days, 86%

LSC-s6d: 60 days, 88%

VSR4/S6e, Virgo/GEO summer run 3.June – 5.September 2011

85%

GEO-HF sensitivity

Frequency [Hz]Strain

[

1/sqrt(H

z)]

Commissioning -2011Squeezing: automatic

alignment, 4+dBIntermediate freq. noise

reduction.30W main laser, new IMC

mirrors, thermal compensation for BS,

->circulating light power increase

Data taking -2012night/weekend modeLonger periods / higher

duty cycle as GEO-HF progresses

Next Step

TAMA/CLIOTAMA is a 300 m baseline Fabry-Perot MichelsonInterferometer with power recycling and achieved the best sensitivity and long observation run earlier than any other long baseline interferometersby 2000.

R&D are being conducted for advanced interferometertechniques for LCGT.

TAMA in Mitaka, Tokyo

CLIO underground at Kamioka

CLIO is a 100 m cryogenic locked Fabry-Perot interferometer placed underground at Kamioka mine.

Thermally limited sensitivity was achieved in 2009 by cooling mirrors down to 10 K. It is a test bench for cryogenic part of LCGT.

Location of LCGTLCGT is planed to be built underground at Kamioka, where the prototype CLIO detector is placed.

Full explanation was given by Shinji

LCGT design Power recycled Fabry-Perot Michelsoninterferometer with Resonant-side-bandextraction

75 w

Double floor isolation systemMounted above cryostat

Cryostat for main mirrors

Main mirror

PTC Heat link

R&D results by TAMA and CLIO for ＬＣＧＴ

TAMA in 2008 (improved after installation of SAS)300 m arm length

CLIO at cryo temperature, 2010/3/7100 m arm length

CLIO limit by roomtemperature

LIGO4 km

LCGT design, 3 km

LIGO-AustraliaA set of Advanced LIGO is planed to be installed at Gingin north of Perth in Western Australia (AIGO project of ACIGA consortium, InDIGO, China)

*) Funding is being requested to Australian government , the result of which will be disclosed, soon.

*) NSF has approved

If realized, the positioning accuracy of sources becomes much improved

LIGO-India • InDIGO (since 2009)Roadmap workshop in

Delhi at University of Delhi, December 2010

• Funding for 3m prototype interferometer at the Tata Institute for Fundamental Research

• Created an Indo-US Center for GWs, funding awarded

• Proposing to participate in LIGO-Australia as a major partner (15%)

• Possible alternative of the case of disapproval of LIGO-Australia

Einstein Telescope Given by Harald

GWIC roadmap of ground based detectors

Will be organized as LIGO-Australia or LIGO-India

L I S ALISA is a joint NASA-ESA space mission of interferometer to see gravity wave events more remotely and more frequently.

- Frequency band: 0.03mHz-0.1Hz, abundantscience objects

- 5 million km baseline length- LISA Pathfinder will be launched in 2013 for the

test of technologies for LISA Preparation of LISA Pathfinder

Orbital motion of LSIA satellites

DECIGODECIGO: Fabry-Perot space interferometer works in frequencies from 0.1 – 10 Hz

Objective:1)Direct observation of the beginning of The Universe2) Measuring the acceleration ofthe Universe

1000 km

DECIGO Pathfinder tests the technologies required to realize DECIGOWill be nominated by the small science spacecraft series run by JAXA/ISAS

AstroWatch recommended by GWIC

• AURIGA and NAUTILUS in operation as an "astrowatch" until LIGO/Virgo resume operation after upgrade

• GEO-HF enters this operation as soon as possible

AURIGA & NAUTILUS continously on the air > 95 %with noise close to Gaussian

(~ 20 outliers/day at SNR>6)until LIGO/Virgo resume

operation

burst sensitivity hrss ~ 10-20 Hz-1/2 or hburst ~ 2x10-19

AUNA: “astrowatch” of AURIGA & NAUTILUS

excercise in recovering injected bursts of 8•10-5 Msolar with coherent wavebursts analysis;

bursts of random ploarization randomly injected in the Galaxy accordingly to the star density;

injections over 1day of AUNA data

detection efficiency vs distanceDistribution in the Galactic plane of the injections (colour) and of the recovered

signals (black)

Summary

• By the first generation detectors of LIGO, GEO, Virgo, TAM/CLIO, we are not in success to catch GW

• This is represented as “starving”, suffering from lack of signal, compared with wealthy astronomers by Bruce Allen

• By two talks in yesterday parallel session; EM follow-up by Marica Branchesi (U Urbino) and first joint analysis with ANTARES by Irene Palma (MPI, AEI) show dynamic approach for signal

• This situation is rescued only by operating more sensitive detectors such as Advanced LIGO, Advanced Virgo, and LCGT, which is firmly confirmed by the previous talk of Alan Weinstein

• We aren’t spiritually starving. We hope that ET will be funded soon and LISA heads along its original strategy