Overview Ground-based Interferometers Barry Barish Caltech Amaldi-6 20-June-05

Amaldi-6 - Interferometer Overview - Barish2 Interferometer Detectors LIGO Louisiana 4000m TAMA Japan 300m Virgo Italy 3000m GEO Germany 600m AIGO Australia future LIGO Washington 2000m & 4000m

20-June-05Amaldi-6 - Interferometer Overview - Barish3 Network of Interferometers LIGO detection confidence GEO Virgo TAMA AIGO locate the sources decompose the polarization of gravitational waves

20-June-05Amaldi-6 - Interferometer Overview - Barish4 Interferometer Concept As a wave passes, the arm lengths change in different ways…. …causing the interference pattern to change at the photodiode Suspended Masses

20-June-05Amaldi-6 - Interferometer Overview - Barish5 Limiting Noise Sources Seismic noise & vibration limit at low frequencies Atomic vibrations (Thermal Noise) inside components limit at mid frequencies Quantum nature of light (Shot Noise) limits at high frequencies Myriad details of the lasers, electronics, etc., can make problems above these levels

20-June-05Amaldi-6 - Interferometer Overview - Barish6 TAMA 300

20-June-05Amaldi-6 - Interferometer Overview - Barish7 Automated Data Taking in DT9 - Master-system (intelligent switching) PC + PCI boards + LabVIEW 64ch digital I/O 16ch A/D + 24ch D/A Lock acquisition Auto adjustment Interface with external system Self-switching sub-system Logic circuit + Embedded micro processor Laser source control MC control Laser intensity stabilization Beam axes control

20-June-05Amaldi-6 - Interferometer Overview - Barish8 Sensitivity in DT9 Recycling gain: 4.5 Extended control band width for the laser frequency Improved strain sensitivity: h =1.7x /Hz

20-June-05Amaldi-6 - Interferometer Overview - Barish9 Observable distance for NS inspiral binaries TAMA

20-June-05Amaldi-6 - Interferometer Overview - Barish10 TAMA Ringdown Analysis

GEO600

20-June-05Amaldi-6 - Interferometer Overview - Barish12 GEO 600 – Optical Layout

20-June-05Amaldi-6 - Interferometer Overview - Barish13 GEO Sensitivity Evolution

20-June-05Amaldi-6 - Interferometer Overview - Barish14 LIGO LIGO Hanford LIGO Livingston

20-June-05Amaldi-6 - Interferometer Overview - Barish15 Evolution of LIGO Sensitivity

20-June-05Amaldi-6 - Interferometer Overview - Barish16 Active Seismic Isolation at LLO  Hydraulic external pre- isolator (HEPI)  Signals from sensors on ground and cross-beam are blended and fed into hydraulic actuators  Status: »Installed on all 4 piers at each of nine vacuum chambers »System is operational

20-June-05Amaldi-6 - Interferometer Overview - Barish17 Active Seismic Isolation at LLO Can lock (and do commissioning work!) during daytime Able to stay locked even when train passes nearby

20-June-05Amaldi-6 - Interferometer Overview - Barish18 LIGO Livingston Sensitivity

20-June-05Amaldi-6 - Interferometer Overview - Barish19 LIGO S4 – Best Performance

20-June-05Amaldi-6 - Interferometer Overview - Barish20 Detection of Periodic Sources  Pulsars in our galaxy: “periodic” »search for observed neutron stars »all sky search (computing challenge) »r-modes  Frequency modulation of signal due to Earth’s motion relative to the Solar System Barycenter, intrinsic frequency changes.  Amplitude modulation due to the detector’s antenna pattern.

20-June-05Amaldi-6 - Interferometer Overview - Barish21 LIGO – GEO Directed Pulsar Search 28 Radio Sources

20-June-05Amaldi-6 - Interferometer Overview - Barish22 GEO-LIGO - Results h 0 95% ULPulsars < h 0 < < h 0 < h 0 > ellipticity  Pulsars <  < <  <  > Lowest 95% UL on h 0 = (J D) Lowest bound on e = (J ) Crab pulsar: h 0 =  = (~30 times spin-down upper limit) Crab pulsar

20-June-05Amaldi-6 - Interferometer Overview - Barish23 Detection of Periodic Sources  Pulsars in our galaxy  Frequency modulation of signal due to Earth’s motion relative to the Solar System Barycenter, intrinsic frequency changes.  Amplitude modulation due to the detector’s antenna pattern. NEW RESULT 28 known pulsars NO gravitational waves  < – (no mountains > 10 cm ALL SKY SEARCH enormous computing challenge

20-June-05Amaldi-6 - Interferometer Overview - Barish24 LIGO Pulsar Search using home pc’s BRUCE ALLEN Project Leader Univ of Wisconsin Milwaukee LIGO, UWM, AEI, APS

20-June-05Amaldi-6 - Interferometer Overview - Barish25 Virgo

20-June-05Amaldi-6 - Interferometer Overview - Barish26 Virgo Seismic Performance Thermal noise

20-June-05Amaldi-6 - Interferometer Overview - Barish27 Virgo - Sensitivity Goal Designed to have good sensitivity at low frequencies

20-June-05Amaldi-6 - Interferometer Overview - Barish28 Virgo Commissioning Extragalactic sensitivity to NS/NS coalescences 55 kpc

20-June-05Amaldi-6 - Interferometer Overview - Barish29 Advanced LIGO Active Seismic Multiple Suspensions Improved Optics Higher Power Laser

20-June-05Amaldi-6 - Interferometer Overview - Barish30 Advanced LIGO Enhanced Systems laser suspension seismic isolation test mass Rate Improvement ~ narrow band optical configuration

20-June-05Amaldi-6 - Interferometer Overview - Barish31 From Amaldi-6 Onwards  From Present Generation Advanced Detectors Next Generation Detectors (QND)  From 8 Mpc (NN inspiral) 200 Mpc and beyond  From Upper Limits Searches Detections  From Generic Waveforms Specified Waveforms  From Single Detectors Global Networks