Final Thoughts and Highlights Barry C Barish Caltech

Final Thoughts and Highlights Barry C. Barish Caltech LISA 24 -June-05 Amaldi-6 - Barish Amaldi-6 Okinawa 24 -June -05

Towards Detection of Gravitational Waves § From LISA Concept § From Bars Demonstrations Mission Bars with Increased Bandwidth Spheres § From Interferometers Advanced Interferometers Generation (QND) Detectors § From 8 Mpc (NN inspiral) § From Upper Limits § From Generic Searches § From Single Detectors 24 -June-05 Next 200 Mpc and then beyond Searches Detections Searches with Specified Waveforms Global Networks Amaldi-6 - Barish 2

Gravitational Waves in Space LISA Three spacecraft, each with a Y-shaped payload, form an equilateral triangle with sides 5 million km in length. 24 -June-05 Amaldi-6 - Barish 3

LISA 24 -June-05 Amaldi-6 - Barish 4

LISA 24 -June-05 Amaldi-6 - Barish 5

LISA 24 -June-05 Amaldi-6 - Barish 6

WD-WD, WD-NS, NS-NS binaries with GW frequency within LISA band are observed. These sources are GUARANTEED Distribution of WD binaries (Nelemans et al) Total number of detatched binaries Total number of interacting binaries 208736473 34291253 24 -June-05 Amaldi-6 - Barish 7 Krolak

Data Analysis Issues Stochastic signal Interacting signals Isolated signals TDI Long wavelength regime Short wavelength regime LISA motion; long observation times; network of detectors 24 -June-05 Amaldi-6 - Barish Krolak 8

LISA 24 -June-05 Amaldi-6 - Barish 9

LISA The diagram shows the sensitivity bands for LISA and LIGO 24 -June-05 Amaldi-6 - Barish 10

DECIGO Bridges the Gap The Japanese Space Gravitational Wave Antenna - DECIGO Deci-hertz Interferometer Gravitational Wave Observatory 10 -18 Strain [Hz-1/2] LISA 10 -20 DECIGO 10 -22 10 -24 24 -June-05 Terrestrial Detectors (e. g. LCGT) 10 -4 10 -2 100 Frequency [Hz] Amaldi-6 - Barish 102 104 11

Sensitivity of DECIGO Force noise= 1/100 of LISA’s 24 -June-05 Amaldi-6 - Barish 12

Resonant Bar Detectors Mini. Grail The Netherlands Auriga, Italy Allegro USA Schenberg Brazil Nautilus, italy Explorer Switzerland 24 -June-05 Amaldi-6 - Barish Niobe Australia 13

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“spheres” • omnidirectionality: decode the excitation of the 5 quadrupolar modes to get uniform sky coverage & find direction of propagation • cross section: larger as the volume fill-up factor in respect to bars Mini. GRAIL (Leiden-Rome) just started operation Talks of Annette de Waard and Luciano Gottardi Schenberg (Brasil) coming to 24 -June-05 Amaldi-6 - Barish 15

DUAL: two nested resonant masses Cerdonio et al PRL (2001), Bryant et al PRD (2003), Bonaldi et al PRD (2003) read-out with non-resonating transducers the differential deformations at frequencies between the lowest quadrupolar modes GW signals add back action noises subtract talk by Michele Bignotto sensitive in a few k. Hz-wide freq band !!! 24 -June-05 Amaldi-6 - Barish 16

sensitivities in the 2006 - 2012 prospective 24 -June-05 Amaldi-6 - Barish 17

Bar Network 24 -June-05 Amaldi-6 - Barish 18

International Gravitational Event Collaboration (IGEC) § ALLEGRO, AURIGA, EXPLORER, NAUTILUS, and NIOBE 1997 -2000. § The search for burst waves at resonant frequency ~ 900 Hz. § The detectors nearly parallel to maximize coincident sensitivity. § Candidate events at SNR > 3 -5 (~ background events 100/day) § Data exchanged: peak amplitude, time of event and uncertainties. § Threshold equivalent to ~0. 1 M⊙ converted into a gravitational wave millisecond burst at a distance of 10 kpc. § The accidental coincidence rate over 1 sec interval (e. g. bandwidth of 1 Hz) was ~ few/week two-fold and ~few/century three-fold. § Time resolution not sufficient to resolve incident wave direction, no directional search has been applied. § No evidence for grav wave bursts was found. 24 -June-05 Amaldi-6 - Barish 19

IGEC coincidence search Upper Limit on the Rate of gravitational waves bursts from the GALACTIC CENTER random arrival times and amplitude search threshold h Final results rate [y – 1] The Area above the blue curve is excluded with a coverage > 90% search threshold h h ~ 2 10 -18 24 -June-05 DE ~ 0. 02 M⊙ converted @ 10 kpc Barish. D 68 (2003) 022001] [P. Astone, et al. Amaldi-6 Phys. - Rev. 20

EXPLORER-NAUTILUS 2001 During 2001 EXPLORER and NAUTILUS were the only two operating resonant detectors, with the best ever reached sensitivity. An algorithm based on energy compatibility of the event was applied to reduce the “background” Excess ? ? ? Number of events Direction of Galactic Disc Sidereal hours ROG Coll. : CQG 19, 5449 (2002) L. S. Finn: CQG 20, L 37 (2003) P. Astone, G. D’Agostini, S. D’Antonio: CQG Proc. Of GWDAW 2002, gr-qc/0304096 E. Coccia ROG Coll. : CQG Proc. Of GWDAW 2002 ROG Coll. : gr-qc/0304004 New data needed 24 -June-05 Amaldi-6 - Barish 21

EXPLORER NAUTILUS Science Run 03 - crewless operation - data validated by cosmic ray effect - new upper limit with bars, no significant coincidence excess nor sidereal effect. ROG S 01 suggestion ROG S 03 24 -June-05 Amaldi-6 - Barish 22

IGEC-2 Expected Performance Triple coincidences: 106 time shifts, no accidentals, 9. 3 days false alarm rate < 10 -4 / yr for H>1. 4 10 -21/Hz Double coincidences: lower false alarm rates than for IGEC-1 My best guess on the achievable upper limit improvement by IGEC-2 rate [year – 1] WARNING: incomplete data set ! IGEC-1 upper limit 1 month dashed region excluded with probability > 90% 1 year search threshold 24 -June-05 Amaldi-6 - Barish 23

TAMA Japan 300 m Interferometer Detectors LIGO Louisiana 4000 m Virgo Italy 3000 m GEO Germany 600 m AIGO Australia future LIGO Washington 2000 m & 4000 m 24 -June-05 Amaldi-6 - Barish 24

TAMA 24 -June-05 Amaldi-6 - Barish Kanda 25

TAMA 24 -June-05 Amaldi-6 - Barish Kanda 26

S 4 Sensitivity 24 -June-05 Amaldi-6 - Barish 27

Noise Progression of the Louisiana Interferometer 24 -June-05 Amaldi-6 - Barish 28

Results for Neutron Star Binaries § Event Candidates » 142 event candidates found in the data » Loudest candidates eliminated in follow up investigation… » Other candidates consistent with background of analysis pipeline § Upper limit set on the rate of BNS coalescences R 90 = 47 / year / MWEG 24 -June-05 Amaldi-6 - Barish 29

Results for Primordial Black Hole Binaries § Same analysis pipeline § Event rate consistent with background of analysis pipeline § Upper limit set on the rate of PBHB coalescences R 90 = 63 / year / MWEG 24 -June-05 Amaldi-6 - Barish 30

Stochastic Background Predictions and Experimental Limits LIGO S 1, 2 wk data -2 100 -4 Cosmic strings (H 2 -L 1) LIGO S 3, 2 month data Nucleosynthesis Ω 0 h 1002 < 4. 4 x 10 -4 (H 1 -L 1) presented Initial LIGO, 1 yrhere data Expected Ω 0 h 1002 < 2 x 10 -6 2 (W 0 h ) 0 Log Ω 0 h 1002 < 23 PRD 69(2004)122004 Laser Interferometer Space Antenna - LISA Pulsar -6 (H 1 -L 1) LIGO band -8 -10 Advanced LIGO, 1 yr data Expected Ω 0 h 1002 < 7 x 10 -10 (H 1 -L 1) Pre-big bang model CMB -12 Inflation EW or SUSY Phase transition -14 Slow-roll Cyclic model -18 -16 -14 -12 -10 -8 f ~ H 0 - one oscillation in the -6 -4 -2 Log ( f [Hz]) 2 4 6 8 10 f ~ 1/Plank scale – red shifted from the Plank era to the present time lifetime of the universe 24 -June-05 0 Amaldi-6 - Barish 31

Conclusions § Sensitivity toward gravitational wave detection is improving on many fronts and this will continue well into the future § New upper limits are being set for the major sources -binary inspirals, periodic sources, burst sources and stochastic background. § Data exchange and joint data analysis between detector groups is improving our ability to make detections § Many exciting future projects and upgrades are planned or getting underway. § Hopefully, detections will be made soon !! Maybe by Amaldi-7? ? 24 -June-05 Amaldi-6 - Barish 32

THANKS Amaldi-6 Organizers!!! 24 -June-05 Amaldi-6 - Barish See at Amaldi-7 Sydney 33