1. THE NEXT GENERATIONS OF GRAVITATIONAL WAVE DETECTORS (*) Giovanni Losurdo INFN Firenze – Virgo collaboration losurdo@fi.infn.it (*) GROUND BASED, INTERFEROMETRIC DETECTORS or… 17 years in 17 minutes

2. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 2 TODAY  LIGO at design sensitivity: technology demonstrated  Virgo and GEO600: more commissioning needed

3. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 3 1st GENERATION DETECTORS 1 101001k10k Frequency [Hz] 10 -22 10 -23 10 -24 10 -25 10 -19 10 -20 10 -21 h [ Hz –1/2 ] GEO600 LIGO VIRGO Resonant Detectors Pulsars NS-NS ~15 Mpc BH-BH ~70 Mpc Supernovae NS vibration 1 ST GENERATION IS CLOSE TO REACHING THE SENSITIVITY TO DETECT A NS-NS COALESCENCE AS FAR AS VIRGO CLUSTER (17MPc) BUT THE EVENT RATE IS TOO LOW !! EXPECTED EVENT RATE: 0.01-0.1 ev/yr (BNS) FIRST DETECTION: POSSIBLE BUT NOT PROBABLE Credit: M.Lorenzini

4. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 4 THE PATH TO 2 nd GENERATION ENHANCED LIGO  Increase the laser power (30 W)  OMC, photodiodes in vacuum  DC detection VIRGO+  Increase the laser power (30-50 W)  Increase the arm cavity finesse  Possibly add monolithic suspension BNS range: 15  33 BNS range: 13  28-49 Exploit available technology to enhance the sensitivity by 2-3x Increase the detection probability by about one order of magnitude. Test solutions for the 2nd generation detectors. 2009

5. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 5 THE PATH TO 2 nd GENERATION  EMPHASIZE HIGH FREQUENCIES: provide scientifically interesting data with GEO until 2014  Perform developments and tests towards third generation detectors  Be up during the LIGO/Virgo upgrade to 2nd generation GEO-HF UPGRADES  Increase the laser power  Reduce coating thermal noise  DC detection  Inject squeezed light GEO HF

6. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 6 FROM DISCOVERY TO ASTRONOMY  GOAL: look 10x further. Detection rate 1000x larger.  2nd generation detectors: Advanced LIGO, Advanced Virgo 100 million light years Enhanced LIGO ~2009 Advanced LIGO ~2014 LIGO today High frequencies: shot noise Mid frequencies: mirror th. noise Low frequencies: seismic noise Low frequencies: pendulum th. noise Credit: R.Powell, B.Berger

7. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 7 ADVANCED LIGO  Approved by NSF. Budget submitted to the President. Signature expected in fall 07.  Construction to start in 2011. Detector up in 2014. BNS range: 15  175 1 ev/week – 1 ev/day expected

8. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 8 ADVANCED LIGO 180 W LASER, MODULATION SYSTEM 40 KG FUSED SILICA TEST MASSES PRM Power Recycling Mirror BS Beam Splitter ITM Input Test Mass ETM End Test Mass SRM Signal Recycling Mirror PD Photodiode ACTIVE SEISMIC ISOLATION FUSED SILICA, MULTIPLE PENDULUM SUSPENSION T ~ 1%

9. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 9 ADVANCED LIGO LARGER BEAM SIZE on test masses (6.0cm radius), to reduce thermal noise MID-HIGH FREQUENCIES: TACKLING THERMAL AND OPTICAL READOUT NOISE ULTRASTABLE HIGH POWER LASER 10  180 W GERMANY - capital investment of MPQ SIGNAL RECYCLING Shaping the response

10. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 10 ADVANCED LIGO ACTIVE VIBRATION ISOLATION Seismic wall: 40 Hz  10 Hz MIRRORS Large and heavier (10  40 Kg) Sub-Angstrom polishing COATINGS Low scatter (<30 ppm) Low losses (  <2·10 -4 ) QUADRUPLE PENDULUM fused silica fibers Susp. fibers Q: few 10 3  3·10 7 UK - capital investment of STFC LOW-MID FREQUENCIES: TACKLING SEISMIC AND THERMAL NOISE

11. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 11 ADVANCED VIRGO  GOALS: – sensitivity: 10x better than Virgo. – timeline: be up with Advanced LIGO.  Conceptual design due to funding agencies Nov 2007 Main foreseen changes: –higher power (optical readout noise) –heavier mirrors (optical readout noise) –better coatings (thermal noise) –signal recycling (shape the curve) –larger beam (thermal noise) –monolithic suspensions (thermal noise)

12. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 12 ONGOING AdV R&D Fiber laser and IMC Optics for high power Detection system Mirror coating Mirror cleaning Optical config. design (Univ. Birmingham) Prototyping/locking New modal optics Electrostatic act. Ribbons for monolithic susp. (Glasgow) New payload design Tiltmeter Improved SA mech.

13. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 13 LCGT  Large scale Cryogenic Gravitational wave Telescope  3 km underground detector, Kamioka mine, Japan  Proposal under consideration for 2008 funding

14. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 14 FROM ASTRONOMY TO COSMOLOGY 10x 1 Hz 3 rd GENERATION: from astronomy to cosmology and fundamental physics –strong field tests of general relativity –understand the source of most energetic phenomena in the Universe –probe the neutron stars e.o.s. –detect high redshift standard candles –…

15. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 15 NEED FOR UNDERGROUND DETECTOR NEWTONIAN NOISE SEISMIC NOISE In 3rd generation detectors the Newtonian noise will be dominant below 10 Hz Credit M.Lorenzini GOAL: PUSH THE DETECTION BANDWIDTH DOWN TO 1 Hz GO UNDERGROUND!

16. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 16 3rd GENERATION BASELINE CONCEPT  Underground detector  Mirrors at cryogenic temperature  Longer arms, new geometry E.T. - Einstein gravitational-wave Telescope  Design Study Proposal submitted to EU within FP7  Large part of the European GW community involved (EGO, INFN, MPI, CNRS, NIKHEF, Univ. Birmingham, Cardiff, Glasgow) Credit: H.Lück

17. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 17 GRB050509B 3 RD GENERATION INTERFEROMETER 2 ND GENERATION 1 ST GENERATION Credit G.Cagnoli NS-NS INSPIRAL RANGE BH-BH INSPIRAL RANGE

18. EPS Conference - Manchester, July 20th, 2007 G.Losurdo – INFN Firenze 18 I NEVER THINK OF THE FUTURE. IT COMES SOON ENOUGH. Albert Einstein 2016: CENTENNIAL OF GENERAL RELATIVITY BIRTH OF GRAVITATIONAL-WAVE ASTRONOMY?