Searching for gravitational waves with lasers

1. Searching for gravitational waves with lasers Rick Savage CaltechLIGO Hanford Observatory - Richland, WA

2. 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 withChan 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 UCLA Symposium F2C@80 Nov. 2009

3. 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 ofgravitational waves • Open an new observationalwindow on the Universe Livingston, LA

4. LIGO Scientific Collaboration 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 • 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 IllesBalears • Univ. of Massachusetts Amherst • University of Western Australia • Univ. of Wisconsin-Milwaukee • Washington State University • University of Washington • Australian Consortiumfor InterferometricGravitational 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. • EötvösLoránd University • University of Florida • German/British Collaboration forthe 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 Centrefor Astronomy and Astrophysics • Louisiana State University • Louisiana Tech University • Loyola University New Orleans • University of Maryland • Max Planck Institute for Gravitational Physics UCLA Symposium F2C@80 Nov. 2009

5. General relativity – gravitational waves “Matter tells spacetime how to curve.Spacetime tell matter how to move.”J. A Wheeler Albert Einstein1916 GW: oscillating quadrupolar strain in spacetime Laser Interferometer UCLA Symposium F2C@80 Nov. 2009

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

7. Capturing the waveform Sketch: Kip Thorne UCLA Symposium F2C@80 Nov. 2009

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

9. Ligo detectors Power Recycled Michelson Interferometer with Fabry-Perot Arm Cavities 4 km-longFabry-Perotarm cavity recycling mirror test masses Laser beam splitter signal UCLA Symposium F2C@80 Nov. 2009

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

11. Isolated environment for test masses UCLA Symposium F2C@80 Nov. 2009

12. Suspended test masses UCLA Symposium F2C@80 Nov. 2009

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

14. 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 wayto reject hypothesis of a compact binaryprogenitor 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. UCLA Symposium F2C@80 Nov. 2009

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

16. Laser source: 10 W to 200 W Diode-pumpedYAG lasers UCLA Symposium F2C@80 Nov. 2009

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

18. Test mass suspensions • Single pendulum • Quadruple pendulumwith reaction masses • 40 kg test masses UCLA Symposium F2C@80 Nov. 2009

19. Time warp – 1763 Boelter Hall UCLA Symposium F2C@80 Nov. 2009

20. To Frank ……. thank you. UCLA Symposium F2C@80 Nov. 2009