1. Michele Punturo INFN Perugia and EGO http://www.et-gw.eu/ 1MGR13- ET

2. Talk outline Presentation of the ET project Planning Science Targets MGR13- ET2 See Sathya talk

3. The Einstein GW Telescope The ET project aims to the realization of a 3 rd generation GW observatory Virgo: 1 st generation GW detector Advanced Virgo: 2 nd generation GW detector ET: 3 rd generation GW observatory The conceptual design phase has been performed in the 2008-2011 years, thanks to the support of the European Commission under the FP7-design studies framework The design document has been delivered in July 2011 MGR13- ET3

4. ET partners MGR13- ET4 EGO VIRGO ET ET Science Team

5. GW interferometer present evolution Evolution of the GW detectors (Virgo example): 2003 Infrastructu re realization and detector assembling 2008 Same infrastructure Proof of the working principle Upper Limit physics 2011 Enhanced detectors V+ Same infrastructure Test of “advanced” techs UL physics 2017 Same infrastructure Advanced detectors First detection Initial astrophysics Commissioning & first runs 5 ASPERA 2012: GW detectors Detection distance (a.u.) year

6. 3 rd generation? Evolution of the GW detectors (Virgo example): 2003 Infrastructu re realization and detector assembling 2008 Same infrastructure Proof of the working principle Upper Limit physics 2011 Enhanced detectors V+ Same infrastructure Test of “advanced” techs UL physics 2017 Same infrastructure Advanced detectors First detection Initial astrophysics 2022 Same Infrastructure (  20 years old for Virgo, even more for LIGO & GEO600) Commissioning & first runs Precision Astrophysics Cosmology 6 MGR13- ET Detection distance (a.u.) year Limit of the current infrastructures 2G+ x 10

7. ET design study driving concepts Realization of a Research Infrastructure ET is an observatory: an infrastructure that lasts for decades, able to host multiple detectors improving with the evolution of the technologies Detection volume as large as possible Limits of the infrastructure (length limitation, environmental noises) reduced Coverage of the widest frequency band (for terrestrial detectors) Internal detectors can be specialized in selected frequency bands, but the observatory covers “all” the possible frequencies MGR13- ET7

8. ET infrastructure The design study resulted in an underground infrastructure, able to host up to 3 detectors, each composed by 2 interferometers The detectors initially installed will be surely less ambitious, but that is a target capability MGR13- ET8

9. How a new infrastructure (and new technologies) pushes ET beyond the 2 nd generation? MGR13- ET9 10 -25 10 -16 h(f) [1/sqrt(Hz)] Frequency [Hz] 1 Hz10 kHz Seismic Thermal Quantum Seismic Newtonian Susp. Thermal Quantum Mirror thermal 3 rd generation ideal target

10. Seismic and Newtonian noises MGR13- ET10 NEWTONIAN NOISE SEISMIC NOISE Credit M.Lorenzini Virgo and advanced Virgo seismic filtering is already close to the top of the possible performances Longer suspensions to facilitate the low frequency access Gravity gradient noise bypasses the seismic filtering

11. Gravity Gradient noise in AdV The GGN noise could limit the AdV sensitivity during high seismic activity days: MGR13- ET11 M. Punturo (VIR-0073B-12) M.Beker (GWADW 2012

12. Seismic noise Virgo and advanced Virgo seismic filtering is already close to the top of the possible performances Gravity gradient noise bypasses the seismic filtering The only way to try to access the 1-10Hz range is to select a site with very low seismic noise We need to minimize Seismic noise Gravity Gradient Noise Environmental noises (wind, human activities, …) 12MGR13- ET

13. Seismic noise model MGR13- ET13 Peterson's background noise model

14. Current GW detectors seismic noise MGR13- ET14  -seism in a very noisy day

15. WP1: Site search: Many sites visited in Europe MGR13- ET15

16. MGR13- ET16 Underground Seismic noise Measurement Underground sites are the most appealing candidates for a very quiet site

17. Day/Night variability vs population density MGR13- ET17

18. Additional noise subtraction schemes under study Gravity Gradient Noise reduction An underground site allows also to suppress the GGN influence MGR13- ET18 ET-B ET-C From c L =200 m/s to c L =2000 m/s G. Cella 2009 Surface -10 m -50 m -100 m -150 m

19. Thermal noise MGR13- ET19 10 -25 10 -16 h(f) [1/sqrt(Hz)] Frequency [Hz] 1 Hz10 kHz Seismic Thermal Quantum Seismic Newtonian Susp. Thermal Quantum Mirror thermal 3 rd generation ideal target

20. Reduction of the thermal noise Thermal noise reduction is achievable through two handles Fluctuation dissipation theorem: Minimization of the mechanical losses in the (suspension and test mass) material and optimization of the suspension geometry Equipartition theorem: reduction of the thermal energy (low temperatures) Advanced detector are fully exploiting the first “handle” Third generation will use the second one: Cryogenics Following talks will describe the cryogenic issues in GW detectors, here just the open questions are raised up. MGR13- ET20

21. KAGRA is pioneering the development of an underground infrastructure and of the cryogenic interferometer for GW detection We considered mandatory to profit of all the collaboration possibilities A 4 years European-Japanese joint project “ELiTES” supported by European Commission under FP7-IRSES is ongoing Exchange of scientists focused mainly on cryogenic issues common to ET and KAGRA MGR13- ET21 Synergies with KAGRA: ELiTES

22. High frequency noise MGR13- ET22 10 -25 10 -16 h(f) [1/sqrt(Hz)] Frequency [Hz] 1 Hz10 kHz Seismic Thermal Quantum Seismic Newtonian Susp. Thermal Quantum Mirror thermal 3 rd generation ideal target

23. High frequency High frequency noise reduction requires the suppression of the quantum noise MGR13- ET23 Shot noise reduction Brute force approach: High power in the FP cavities High power laser High reflectivity Thermal lensing issues Difficult cross-compatibility with cryogenics Parametric instabilities QND techniques: squeezing Iper-Promising (12.7dB @5MHz), 3.4dB in GEO, 2dB in LIGO test Frequency dependent implementation New infrastructures

24. ET sensitivity (Xylophone strategy) Implementing all the technologies under study for ET a target sensitivity (ET-B) can be draft MGR13- ET24 Doubts on the cross-compatibility of the technologies Need to simplify the problem Xylophone strategy

25. Beyond Advanced Detectors Let suppose to gain a factor 10 wrt the Advanced detectors: What could we do? Astrophysics: Measure in great detail the physical parameters of the stellar bodies composing the binary systems NS-NS, NS-BH, BH-BH Constrain the Equation of State of NS through the measurement of the merging phase of BNS of the NS stellar modes of the gravitational continuous wave emitted by a pulsar NS Contribute to solve the GRB enigma Relativity Compare the numerical relativity model describing the coalescence of intermediate mass black holes Test General Relativity against other gravitation theories Cosmology Measure few cosmological parameters using the GW signal from BNS emitting also an e.m. signal (like GRB) Probe the first instant of the universe and its evolution through the measurement of the GW stochastic background Astro-particle: Contribute to the measure the neutrino mass Constrain the graviton mass measurement 25 MGR13- ET

26. ET Strategy MGR13- ET26

27. GW Strategy GW has a common strategy: Complete the current upgrade of the “Advanced” detectors Detect GW GW & H202027  Start the precision GW astronomy and astrophysics adventure through the ET project H. Lück, 5 th ET symposium, Hannover Oct.2013

28. 20202012201320142015201620172018201920212022202320242025 R&D Technical design Site preparation 202620272028 First detection on advanced interferometers 2029 28 ET Conceptual design ET Observatory Funding ELiTES ET Site and infrastructures realisation Horizon 2020 Preparatory phase 5th ET meeting GraWIToN EGWII H2020 - IA