LIGO Laser Interferometer Gravitationalwave Observatory ETH Zrich October

LIGO Laser Interferometer Gravitational-wave Observatory ETH Zürich, October 2008 Daniel Sigg, LIGO Hanford Observatory G 080441 -00 -D ETH Zürich

LIGO Scientific Collaboration University of Michigan University of Minnesota The University of Mississippi Massachusetts Inst. of Technology Monash University Montana State University Moscow State University National Astronomical Observatory of Japan Northwestern University of Oregon Pennsylvania State University Rochester Inst. of Technology Rutherford Appleton Lab University of Rochester San Jose State University Univ. of Sannio at Benevento, and Univ. of Salerno University of Sheffield University of Southampton Southeastern Louisiana Univ. Southern Univ. and A&M College Stanford University of Strathclyde Syracuse University Univ. of Texas at Austin Univ. of Texas at Brownsville Trinity Universitat de les Illes Balears Univ. of Massachusetts Amherst University of Western Australia Univ. of Wisconsin-Milwaukee Washington State University of Washington Australian Consortium for Interferometric Gravitational Astronomy The Univ. of Adelaide Andrews University The Australian National Univ. The University of Birmingham California Inst. of Technology Cardiff University Carleton College Charles Sturt Univ. Columbia University Embry Riddle Aeronautical Univ. Eötvös Loránd University of Florida German/British Collaboration for the Detection of Gravitational Waves University of Glasgow Goddard Space Flight Center Leibniz Universität Hannover Hobart & William Smith Colleges Inst. of Applied Physics of the Russian Academy of Sciences Polish Academy of Sciences India Inter-University Centre for Astronomy and Astrophysics Louisiana State University Louisiana Tech University Loyola University New Orleans University of Maryland Max Planck Institute for Gravitational Physics G 080441 -00 -D ETH Zürich 2

Scientific Goals of LIGO q Discover the gravitational waves predicted by General Relativity q G 080441 -00 -D ETH Zürich Use gravitational waves to pioneer a new window on the universe 3

What is the observable effect? Example: Ring of test masses responding to wave propagating along z Amplitude parameterized by (tiny) dimensionless strain h: G 080441 -00 -D ETH Zürich 4

Arial View of the LIGO Sites LIGO Livingston Observatory LIGO Hanford Observatory G 080441 -00 -D ETH Zürich 5

Power-Recycled Michelson Interferometer with Fabry-Perot Arm Cavities G 080441 -00 -D ETH Zürich 6

Main Features q q q q 4 km vacuum envelope 10 -9 torr Seismic isolation stack Suspended masses 10 W Nd: YAG laser, 1064 nm Suspended mode cleaner Feedback controls for length and alignment Physical environment monitor G 080441 -00 -D ETH Zürich 7

S 4 Sensitivity G 080441 -00 -D ETH Zürich 8

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Time Line 1999 3 2000 4 1 2 3 2001 4 1 2 2002 4 3 Inauguration First Lock 4 K strain noise 10 -17 2 1 4 1 2 3 2004 4 1 Full Lock all IFO 10 -18 Science 3 2003 10 -20 10 -21 S 2 2 3 2005 4 1 2 First Science Data 4 1 2 3 4 2008 1 2 3 2009 4 1 2 S 4 4 1 2 3 2011 4 1 2 3 4 at 150 Hz [Hz-1/2] S 6 S 5 1 year of Coincidence Data Enhanced LIGO ETH Zürich 3 2010 Now 3 x 10 -23 Installation and Commissioning G 080441 -00 -D 3 2007 Design Sensitivity 10 -22 S 3 3 2006 Runs Advanced LIGO 11

The 5 th Science Run G 080441 -00 -D ETH Zürich 12

Accumulated triple-coincidence Duty factor is for operating all THREE interferometers in SCIENCE MODE 1 yr = 8765. 8 hrs 67% 48% Jan 1, 2006 G 080441 -00 -D Apr 1, 2006 Jul 1, 2006 Oct 1, 2006 Jan 1, 2007 ETH Zürich Apr 1, 2007 Jul 1, 2007 Oct 1, 2007 13

Signal duration and template unmodeled matched filter G 080441 -00 -D Short duration Long duration Burst search Stochastic search Inspiral search CW search ETH Zürich 14 Credit: NASA/CXC/ASU/J. Hester et al.

GRB 070201 q q G 080441 -00 -D Short, hard gamma-ray burst Ø A leading model for short GRBs: binary merger involving a neutron star Position (from IPN) consistent with being in M 31 (Andromeda) LIGO H 1 and H 2 were operating Result from LIGO data analysis: No plausible GW signal found; therefore very unlikely to be from a binary merger in M 31 ETH Zürich 15

Crab Pulsar Model Chandra image Result from first 9 months of S 5: Consistent with Gaussian noise Upper limits on GW strain amplitude h 0 Single-template, uniform prior: 3. 4× 10– 25 Single-template, restricted prior: 2. 7× 10– 25 Multi-template, uniform prior: 1. 7× 10– 24 Implies that GW emission accounts for ≤ 4% of total spin-down power Multi-template, restricted prior: 1. 3× 10– 24 G 080441 -00 -D ETH Zürich 16

Search for a Stochastic GW Background q Cross-correlated LIGO data streams to estimate energy density in isotropic stochastic GW, assuming a power law Partial, preliminary result from S 5 is comparable to constraint from Big Bang nucleosynthesis John T. Whelan for the LSC, AAS Meeting, Jan 2008 q G 080441 -00 -D ETH Zürich 17

Known pulsars Timing by Jodrell Bank Pulsar Group G 080441 -00 -D ETH Zürich 18

Binary Neutron Star Sources Single detector, SNR=8, averaged Milky Way ~ 1. 6 x L 10 No detection so far G 080441 -00 -D ETH Zürich 19

Network Analysis 4 km 2 km EXPLORER 4 km 600 m 3 km AURIGA NAUTILUS 300 m 100 m CLIO ALLEGRO Bar / Sphere Interferometer Mario Schenberg G 080441 -00 -D ETH Zürich 20

Enhanced LIGO G 080441 -00 -D ETH Zürich 21

Key Technologies q In-vacuum output mode cleaner Ø Currently installed and being commissioned Ø New advanced LIGO seismic isolation q DC readout scheme Ø Crucial for advanced LIGO q 30 W laser (LZH/Hannover) Ø First stage of advanced LIGO laser Ø Will require bigger thermal compensation system q Input optics Ø New high power Faraday isolator & Pockels cells q New earthquake stops (fused silica tipped) G 080441 -00 -D ETH Zürich 22

Advanced LIGO q q Funding approved at the beginning of this year! An order of magnitude improvement in sensitivity 100 million l-y Ø 3 orders of magnitude improvement in rate! G 080441 -00 -D ETH Zürich 23

Key Technologies q Active seismic isolation system Ø Hydraulic pre-isolator Ø 2 stage in-vacuum isolation system q q Multiple suspension stages 30 kg test masses Ø Active thermal compensation q 180 W laser source Ø High power input optics q q Signal recycling added In-vacuum detection benches G 080441 -00 -D ETH Zürich 24

Summary q q q First relevant science results are published! And more to come… All LIGO interferometers are at design sensitivity For sources like binary neutron star and black hole coalescence we can see well into the Virgo cluster The first big science run is done with 1 year of coincidence data Enhanced LIGO commissioning is in progress Advanced LIGO is funded We should be detecting gravitational waves regularly within the next 10 years! G 080441 -00 -D ETH Zürich 25