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

Black holes and time warps Transferred to UCLA in Physics in 1974 Jan 1975 Started working for F. Chen and N. Luhmann as undergraduate lab assistant (with Doug Cook) Alain Semet, John Turcek, Steve Obenschain, Jim Holt, Mark Herbst, et al. 1976-1986 Plasma diagnostics N. Luhmann, T. Peebles, H. Fetterman, et al. Microtorr, macrotorr, UT FRC, FIR lasers, CO2 lasers 1986 – 1992 Laser / Plasma interactions Graduate school in EE at UCLA – Chan Joshi Masters thesis – Degenerate four-wave mixing in heated CO2 gas PhD thesis – Frequency upshifting of electromagnetic radiation via an underdense relativistic ionization front 1992 – present LIGO project – Caltech until 1997 then LIGO Hanford Observatory in Richland, WA LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

http://www.einsteinsmessengers.org/ 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 an new observational window on the Universe Livingston, LA

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 tell 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

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

Do they exist? Indirect evidence (Weisberg, Taylor) Pulsar System PSR 1913 + 16 (R.A. Hulse, J.H. Taylor Jr, 1975) A 17/sec pulsar (neutron star in rapid rotation, emanating periodic pulses of electromagnetic radiation) orbits around a neutron star with period = 8 hours Only 7kpc away General Relativity prediction: the orbital radius diminishes 3mm/orbit; a collision is expected in 300 million years The rotation period diminished 14 sec in 1975-94; energy loss Optimum agreement with the predictions of general relativity: the energy is carried away by gravitational waves! The “inspiral” will accelerate at the end, when the neutron stars coalesce Gravitational wave emission will be strongest near the end Orbit will continue to decay over the next ~300 million years, until coalescence Gravitational wave emission will be strongest near the end LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

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

Sources Coalescing Binary Systems Credit: AEI, CCT, LSU Coalescing Binary Systems Neutron stars, low mass black holes, and NS/BS systems Credit: Chandra X-ray Observatory ‘Bursts’ galactic asymmetric core collapse supernovae cosmic strings ??? Casey Reed, Penn State NASA/WMAP Science Team Cosmic GW background stochastic, incoherent background Continuous Sources Spinning neutron stars probe crustal deformations 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

iLigo hardware LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

S5 Science Run Nov 2005 – Oct 2007 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

LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009 108 ly Enhanced LIGO LIGO today Credit: R.Powell, B.Berger Adv. LIGO LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

10 W to 200 W laser source LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Single to quadruple pendulum LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Passive to active vibration isolation LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Time warps UCLA Laser/Plasma interactions LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

LIGO Scientific Collaboration LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Laser Interferometer Gravitational-wave Observatory Started as a collaboration between Caltech and MIT Goal: direct observation of gravitational waves Open a new observational window on the Universe 3 k m ( ± 1 s ) CALTECH Pasadena MIT Boston HANFORD Washington LIVINGSTON Louisiana LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

LIGO Hanford Observatory South-central Washington Where Columbia, Yakima, and Snake rivers converge LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

Frank’s thinking ….. inflatable kiyak ? …. LIGO Doug Cook Columbia River credit: Google Maps LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009

closer look – more lasers and optics LIGO-G0901004 UCLA Symposium F2C@80 Nov. 2009