Searching for gravitational waves with lasers Rick Savage Caltech LIGO Hanford Observatory - Richland, WA

Black holes and time warps Sept 1974 - transferred to UCLA in Physics Jan 1975 - started working for F. Chen and N. Luhmann as undergraduate lab assistant (with Doug Cook) 1976 to1986 - plasma diagnostics with N. Luhmann, T. Peebles, H. Fetterman, et al. 1986 to 1992 - graduate school in EE at UCLA with Chan Josh, Warren Mori, Ken Marsh, Chris Clayton, et al. Masters thesis – Degenerate four-wave mixing in heated CO2 gas PhD thesis – Frequency upshifting of electromagnetic radiation via an underdense relativistic ionization front 1992 to present - LIGO project at Caltech until 1997 then LIGO Hanford Observatory in Richland, WA LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

LIGO: Laser Interferometer Gravitational-wave Observatory Hanford, WA MIT 3002 km (L/c = 10 ms) Caltech Managed and operated by Caltech & MIT with funding from NSF Goal: Direct observation of gravitational waves Open a new observational window on the Universe Livingston, LA LIGO-G0901004

LIGO Scientific Collaboration 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 CSU Fullerton Embry Riddle Aeronautical Univ. Eötvös Loránd University 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 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 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 University of Strathclyde Syracuse University Univ. of Texas at Austin Univ. of Texas at Brownsville Trinity University Tsinghua University Universitat de les Illes Balears Univ. of Massachusetts Amherst University of Western Australia Univ. of Wisconsin-Milwaukee Washington State University University of Washington LIGO Scientific Collaboration LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

General relativity – gravitational waves “Matter tells spacetime how to curve. Spacetime tells matter how to move.” J. A Wheeler Albert Einstein 1916 GW: oscillating quadrupolar strain in spacetime Laser Interferometer LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Potential sources Coalescing Binary Systems Burst Sources Credit: AEI, CCT, LSU Coalescing Binary Systems neutron stars low mass black holes NS/BS systems Credit: Chandra X-ray Observatory Burst Sources galactic asymmetric core collapse supernovae cosmic strings ??? Casey Reed, Penn State Continuous Sources spinning neutron stars probe crustal deformations NASA/WMAP Science Team Cosmic GW background stochastic incoherent background LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Capturing the waveform Sketch: Kip Thorne LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Detection of gravitational waves Michelson interferometer - differential length change sensor LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

LIGO detectors Power recycled Michelson interferometer Laser 4 km-long Fabry-Perot arm cavity recycling mirror test masses beam splitter Power recycled Michelson interferometer with Fabry-Perot arm cavities signal LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Beam tubes and chambers 1.2 m diameter LN2 pumps at ends P < 1e-09 torr dominated by H2 LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Isolated environment for test masses LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Suspended test masses LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Initial LIGO displacement sensitivity Antenna patterns NS-NS binary inspiral range ~ 15 Mpc (S/N = 8) + pol S5 science run 11/05-10/07 G pol avg LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Scientific results of S5 run No detections (so far) - data still being analyzed Astrophysical results – upper limits “If LIGO didn’t detect it, then it can’t be bigger than …” CRAB pulsar – “no more than 4 percent of the energy loss of the pulsar is caused by the emission of gravitational waves.” (ApJL 683, L45) Gamma ray burst GRB 070201 – LIGO “results give an independent way to reject hypothesis of a compact binary progenitor in M31” (ApJ 2008, 681, 1419) Upper limit on the stochastic gravitational wave background (http://www.nature.com/nature/journal/ v460/n7258/pdf/nature08278.pdf) Credits for X-ray Image: NASA/CXC/ASU/J. Hester et al. Credits for Optical Image: NASA/HST/ASU/J. Hester et al. LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

What’s next? Advanced LIGO Quantum noise limited interferometer Factor of 10 increase in sensitivity Factor of 1000 increase in event rate LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Laser source: 10 W to 200 W Diode-pumped YAG lasers LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Vibration isolation: passive to active Masses and damped springs Geophones and accelerometers on payload Active feedback control – 6 deg. of freedom LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Test mass suspensions Single pendulum Quadruple pendulum with reaction masses 40 kg test masses LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Time warp – Rm.1763 Boelter Hall LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

To Frank ……. thank you. LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009