Gravitational Wave Detector Arrays Benefits of a Southern Hemisphere Detector David Blair On behalf of the LIGO-Australia Collaboration Flashback! Moriond 2007

Host Galaxy Identification Wen, Howell, Coward, Blair Moriond 2007 How many galaxies in average error box as function of event distance? What fraction of coalescence events can be uniquely linked to galaxies in absence of EM identification? Answer: NS-NS~2% without AIGO, ~25% with AIGO. BH-BH ~ few percent with AIGO

Mean efficiency for all networks, as function of inspiral distance

All sky direction angular resolution maps HHLV (top) compared with AHLV (bottom)

Why is localisation Important? Identify EM counterpart Identify host galaxy even without EM counterpart Improve parameter estimation Reduce noise

Genesis of LIGO-Australia Moriond 2007 : Host Galaxy Identification by a Worldwide Array of Gravitational Wave Detectors 2009: Gravitational Wave International Committee Roadmap for next 30 years: Need for southern hemisphere detector 2009: Australia-India Collaboration: creation of IndIGO Consortium Shanghai : International Collaboration in Gravitational Astronomy Conference: China Gravitational Wave Working Group formed. 2010: AIGO Conference, Perth: discussion about Advanced LIGO detector re-location to Australia. 2010: Weiss Committee: Science case for Advanced LIGO detector location in Australia. 2010: LIGO White Paper on LIGO-Australia (new name) 2010: NSF and National Science Board endorse proposal 2011: IndIGO-LIGO-Australia meeting Delhi 2011: LIGO-Australia and IndIGO proposals submitted

Angular Resolution Reducing the source error ellipse

Binary Inspirals are Standard Sirens Waveform determines: Distance from the earth r, Masses of the two bodies, Orbital eccentricity e, Orbital inclination i e = 0e = 0.3 e = 0.6e = 0.8 dependence on i for e = 0 Mass ~ f, df/dt

Polarisation Coverage on Sky Adding LIGO- Australia reduces the sky area with poor polarisation coverage.

Parameter Estimation Orbital inclination distance

LIGO-Australia USA: LIGO Lab: One Advanced LIGO detector to be transferred to Australia instead of installation at Hanford Germany: Prestabilised high power laser UK: Test mass suspension and local controls India: Vacuum tanks for interferometer components China: Personnel for installation and operations and R and D for instability control. Australia:

ACIGA Universities and Facilities Australian National University Monash University Gingin High Power Test Facility

_____________________________________________________________________________ All components for a complete advanced interferometer Training opportunities for LIGO-Australia staff and associate international collaborators Expert assistance with the interferometer components as required (assembly, commissioning, operating) Partial initial support for director LIGO Laboratory Contribution

Existing 80m interferometer Gravity Discovery Centre Zadko Robotic Telescope Leaning Tower of Gingin Cosmology Gallery Magnetic Observatory

Earth berms reduce wind loads Photovoltaic DC power, LED lighting. Geothermal cooling

Beam tube: 1.2m diam, mostly buried

The site is in Yeal Nature Reserve near Gingin, ~80km from Perth

LIGO-Australia science benefits Angular resolution enables identification of host galaxies at reasonable distance (improves H 0 estimation by factor 2-3) Enables associated EM signals to be detected Joint EM-GW searches can look times deeper: (3 - 8 times more sources) LIGO-A directly improves array sensitivity: ~50% more detectable sources For stochastic background LIGO-A enables cross correlation between 10 independent baselines (instead of 3 or 6) LIGO-A improves parameter estimation for fundamental testing of general relativity: (more sky area, better polarisation sampling). LIGO-A Non-Gaussian noise reduced by large factor Array on-time duty cycle improves.

LIGO Australia Summary LIGO Lab has offered to locate the third advanced LIGO interferometer in Australia The NSF and National Science Board has approved this The offer is subject to Australia providing: --- The infrastructure to house and operate the interferometer --- The funds/ people to install the detector --- The funds / people to operate the detector for 10 years Decision to accept/decline offer required by Oct 2011 Detailed proposal to Australian Federal Government submitted

Conclusion This is the best opportunity we have ever had. The decision is political. Suggestions as to how we can convince the Australian Government welcome. Proposal available at or from me. We have a nice video : google “LIGO-Australia video” to find it on youtube.

Australian Consortium

LIGO-Australia : An International Partnership Australia: Australian Consortium for Gravitational Astronomy –5 Universities, CSIRO, Industry USA: LIGO Laboratory (Caltech +MIT) India: IndIGO Consortium Germany: Max Planck Institute for Gravitational Physics: Albert Einstein Institute Britain: (Glasgow, Cardiff, Birmingham) China Gravitational Wave Working Group CGWG Project Cost ~$300M, US contributing 50% –Approved by NSF and National Science Board

Cosmology with Binary Inspirals Use Standard Siren measured distance combined with directional information to identify host galaxy (difficult without AIGO…see later) Measure red shift of host galaxy Determine Hubble Constant H and Dark Energy Parameter w Search for EM outburst (BBH may have no EM counterpart) If there is an EM counterpart can measure GW velocity compared with EW velocity: test MOND theories etc.

World GW telescope requirements Enough sensitivity for frequent events Dual Polarisation sampling for distance estimation Angular resolution for host galaxy identification EM telescopes for confirmation, source identification. –Afterglows: fast transient searches –Pulsar glitches: multiple pulsar monitoring –Pulsars: precise ephemeris monitoring –X-ray binaries: ephemeris monitoring –Supernovae: wide field transient searches

World GW Detector Array All sky monitor with ability to look in all sky directions with high angular resolution. Spherical earth naturally improves polarisation coverage. Initial detectors (LIGO and Virgo) aligned for optimum coincidence detection, –null polarisation coverage, – poor angular resolution