five long and independent baselines: better snr and much better directional resolution

Proposal to extend current AIGO High Optical Power research facility to a 5km advanced interferometer.

D G Blair on behalf of ACIGA

LIGO-G060284-00-Z

Five long and independent baselines:

Better SNR and much better directional resolution

Why is AIGO necessary

• Increased angular resolution :– average x 4– sometimes much more

• Coherent array analysis– increases the number of detectable sources x ~2

• Reduced Accidental coincidences– reduces as number of independent baselines to power N

Pacc ~t

c

R c N

Improved angular resolution with AIGO

• LIGO and VIRGO •LIGO, VIRGO and AIGO

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The Process So Far• Gingin facility development 2000-2005• Western Australia funds Centre of Excellence for

gravitational astronomy 2005• AIGO Planning meeting Oct 2005: concept for

reduced pipe diameter.• WA Govt forms Steering Committee for AIGO

Nov 2005.• International Letter Writing Nov 2005…thanks!!• UWA and State Govt fund prospectus document

Dec 2005 and planning process May 2006.• ACIGA costing and planning:(LIGO support

through Adv LIGO review) May 2006.

Gingin facility Investment

• Clean rooms and assembly facilities

• Vacuum system and vacuum automation

• High optical power laser facilities

• Seismic surveying demonstrating excellent seismic attenuation.

• Roads and power infrastructure.

• Total investment so far ~ $20M

AIGO Concept

• AIGO: I for International• An Advanced detector built using maximum

knowhow, support and contribution from northern hemisphere detectors.

• A detector planned and advised internationally.• Utilising the best aspects of all detectors built to

date, combined with certain innovative features.• A detector that will feed data directly into the

international data analysis grid.

AIGO Realities

• Funds ~ $40m thought to be possible in Australia• Funds ~$10m available soon for pipe infrastructure.• Substantial data analysis effort funded separately.• Can we build an advanced detector for such a small

sum?• Not without international support

– Control systems

– Designs

– Monitoring

– Expertise in many areas

– Advisory committees

AIGO Preliminary Concept• 5km, 700mm diameter vacuum pipe (de Salvo)• keyhole welding, precision weld monitoring (CSIRO)• on site fabrication of pipe in long lengths (Duraduct)• spiral band saw baffle fabricated with pipe.(de

Salvo,Duraduct)• Low mass enclosure, solar bakeout. (VACUUM 44: 2,151-154 ( 1993)).

Light Scattering Noise (Takahashi)

• Modelling based on R Takahashi et al PRD 70,06,2003

• Number of effective baffles N:h=height of baffle,d=baffle spacing

N h

d

L

R

Spiral baffle represents significant overkill

Why 5km

• Arm length dilutes test mass thermal noise.

• Thermal noise penalty for parametric instability suppression by ring damping.

• Adv LIGO proposed performance can be regained with extra arm length.

Strong Thermal Lensing

Observation and compensation (PRL accepted 2006)

Parametric Instability (PRL2005)

Stabilisation requires ring damping: extra thermal noise. (see Ju Li’s talk)

Consortium

About 70 people

7 AustralianUniversities

2 CSIRO Institutes

2 Companies

Conclusion

• AIGO offers significant benefit to existing terrestrial detectors.

• Natural next step for world network.

• Can be achieved over next 8 years with community support.

• We would like to sign MOUs with organisations such as VESF

Thermal Gradient: Jerome Degallaix

Cavity Waist Position

Thermal compensation

Heat the compensation plateInput Test Mass

R1 =

Demonstrated Thermal Compensation

0.1

1

10

100

718 719 720 721 722

Radius of Curvature (m)

Max

imum

R o

f all

acou

stic

m

odes

Gingin prediction, Fused Silica

0.1

1

10

100

718 719 720 721 722

Radius of Curvature (m)

Max

imum

R o

f all

acou

stic

mod

esGingin prediction, Sapphire

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Astro-ph/061275Short GRB and binary black hole standard sirens as a probe of dark energy

Authors: Neal Dalal (CITA), Daniel E. Holz (LANL and U. Chicago), Scott A. Hughes (MIT), Bhuvnesh Jain (U. Penn.)

Comments: 8 pages, submitted to PRD

Short gamma-ray bursts, if produced by merging neutron star binaries, would be standard sirens with known redshifts detectable by ground-based GW networks such as LIGO-II, Virgo, and AIGO. Depending upon the collimation of these GRBs, a single year of observation of their gravitational waves can measure the Hubble constant to about 2%. When combined with measurement of the absolute distance to the last scattering surface of the cosmic microwave background, this determines the dark energy equation of state parameter w to 9%.

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