Probing Dynamical Spacetimes

Transcription

1 Probing Dynamical Spacetimes Scientific exploitation of Advanced Virgo Nikhef SAC, April 24, [email protected] Outline Motivation Aim and focus Composition of consortium Requested positions versus aim Coherence and added value

2 Einstein gravity : G 8 T Gravity as a geometry Space and time are physical objects Gravitation Least understood interaction Large world-wide intellectual activity Theoretical: ART + QM, Cosmology Motivation Experimental: Interferometers on Earth and in space Gravitational waves Dynamical part of gravitation, all space is filled with GW Ideal information carrier, almost no scattering or attenuation The entire universe has been transparent for GWs, all the way back to the Big Bang Aim and focus To Detect and Observe Gravitational Waves Focus on 3 activities Scientific promise Direct discovery of gravitational waves Fundamental physics, cosmology and astrophysics Towards gravitational wave observatories Bundle existing strengths (astro)particle physics: experiment and theory Astrophysics, astronomy and cosmology Multi-disciplinary physics program R.A. Hulse and J.H. Taylor Jr (1993)

3 Advanced LIGO and Virgo First common run in 2016 Kagra joins 2020 LIGO India? Kagra, Kamioka, Hida, Japan Evolution of sensitivity

4 1 st Generation interferometers Nominal sensitivity achieved Virgo: low frequency performance 1.2 years of scientific data taking No detection 1 st Generation interferometers Nominal sensitivity achieved Virgo: low frequency performance 1.2 years of scientific data taking No detection

5 Direct discovery of GW Advanced Virgo Improve sensitivity by factor 10 From Virgo cluster to Local supercluster This yields a factor 1000 increase in event rate! Probable sources Astronomy: we know GW sources exist! Binary black hole coalescence Binary neutron star mergers, supernovae, pulsars BNS Rates: (most likely and 95% interval) Initial Virgo (30Mpc) 1/100yr (1/500-1/25 yr) Advanced detectors (350Mpc) 40/yr (8-160/yr) Kalogera et al.; astro-ph/ BBH more difficult to predict Advanced Virgo PROJECT GOALS Upgrade Virgo to a 2 nd generation detector. Sensitivity: 10x better than Virgo Be part of the 2 nd generation GW detectors network. Timeline: data taking with Advanced LIGO Improvements High quality optics Heavier mirrors Low absorption Coating thermal noise 0.2 nm rms surfaces Thermal compensation Monolithic suspensions Sensing devices under vacuum Larger beams Modification of UHV system Signal recycling Challenge

6 NL contributions Nikhef Input Mode Cleaner Cryolinks Seismic attenuation systems Linear alignment and phase camera s External injection bench Priority of commissioning EIB is the last bench before laser beam enters the vacuum First stage in the commissioning process

7 External injection bench SAS features Single-stage attenuation system Six degrees of freedom Sensors: 6 accelerometers, 6 LVDTs Consistent with m/rthz Compact design Installed and tested in Virgo EIBSAS was first major installation of AdV EIBSAS: finishing touch(es) Mathieu Blom November 18, 2013

8 Laser bench EIBSAS in Advanced Virgo EIBSAS IIB Install optics: Q Commission controls: Q EIBSAS: new TF with PZT driven shaker Input mode cleaner IMC Triangular cavity High finesse, 145 m length First stage in frequency stabilization Dihedron Complex optical component Manufactured by Dutch industry: Optronica Also produced the end mirror(s) Marine: zorg dat je erbij komt Optronica Marinebedrijf Den Helder

9 Input mode cleaner IMC end-mirror system Mirror payload Including marionette Installed in Q First optical payload installed in Advanced Virgo Commissioning now in progress Crucial to stay on timeline Thomas Bauer Marko Kraan Advanced Virgo

10 Our first installations in AdV Installation completed Commisioning in progress Cryolinks Cryolink features Four LN2 links: mbar region Designed by Nikhef Factory acceptance completed Installation schedule First link in May 2014 Controls and safety systems Completed in November 2014

11 nv/sqrt(hz) Optical sensing systems Angular alignment DC QPD sensing at WE (B8) and NE (B7) RF sensing Up to 131 MHz Phase camera s RF sensing of cavity fields Amplitude and phase distribution For all wave fields (i.e. side bands) Optical sensing systems QUAD OPA Shot noise limited 1000 Q2 Q3 Q1 100 Shot noise lightt Q Freq [Hz]

12 Phase camera s: 3D imaging Imaging of cavity fields Both carrier and sidebands f1 = MHz f2 = MHz f3 = MHz f4 = MHz f5 = MHz fh= MHz Amplitude and phase High speed imaging of HOM Avoid moving parts (CCD based) AdV optical design: MSRC Main diagnostics for Advanced Virgo Input for Thermal Compensation Systems Martin van Beuzekom Kazuhiro Agatsuma Femtometer/ Hz isolation

13 Production for AdV SPRB SWEB SNEB SIB2 SDB2 Horizontal geophones Production for AdV E. Hennes A. Rietmeijer L. Ceelie M. Jaspers W. Kuilman P. de Groen J. Soede

14 MultiSAS challenges Requirement Expected performance Controls Optical levers MultiSAS schedule

15 National context National APP Strategic Plan Nikhef strategic plan PTA, elisa, Astronomy, Theory communities Astrophysics at RU Joined Virgo in May 2012 First Astrophysics group in Virgo BlackGEM Proposal Approved by NOVA Phase-4 Instrum. Prop. Design phase approved, with PHASE-I reservation Black-hole merger GW-EM radiation array Third GW meeting Astron, Feb. 7, 2014 Multi-messenger astronomy GW signal in astrophysical context Give precise localization Identify host galaxy Multi-messenger picture of most energetic events Insight into physics of progenitors Mass, spin, distance Environment: temperature, density, redshift Received 64 applications so far...

16 International context Nikhef Kagra collaboration in ELiTES EU funded technology transfer from Nikhef to Kagra Einstein Telescope On ApPEC readmap; Listed as A-Topic for Horizon 2020 Nikhef leads JRA3 on site selection and gravity gradient noise University of Tokyo, December 5, 2013 November 28, 2013: elisa approved! arxiv: v1

17 GW antenna in space - elisa 3 spacecraft in Earth-trailing solar orbit separated by 10 6 km. Measure changes in distance between fiducial masses in each spacecraft ESA funded Launch date 2034 LISA pathfinder

18 Science goals What happens at the edge of a Black Hole? Chandra - Each point of x-ray light is a Black Hole! First model-independent precision test of strong field dynamics of spacetime using signals from coalescing compact binaries Robust against unknown instrumental features (e.g. calibration errors) Robust against currently unknown GR effects (e.g. neutron star tidal effects) Expand to BBH, pure spacetime process, rich dynamics Prompted formation of new LSC-Virgo technical subgroup, led by Del Pozzo Is Einstein s theory still right in these conditions of extreme gravity? Or is new physics awaiting us? Tests of post-newtonian theory Test of GR without assuming alternative model Based on post-newtonian phase expansion of BBH inspiral signal Single (2, 20) M sun BBH merger (zero spin): PN coefficients all depend on only the component masses. Thus only two are independent Fit to a model where three PN coefficients are treated as independent Test non-linear predictions (e.g. tail terms, logarithmic terms) Van Den Broeck, Li, Del Pozzo, Vitale

19 Compact binary coalescence elisa Mass at source Mass ratio Spin magnitudes Distance to the source GW signal detected months before merger Signal visible by eye in data stream BH merger rate elisa: from a handful up to a few hundred events per year SNR Kerr metric is the unique end state of gravitational collapse Based on assumptions Spacetime is vacuum, axisymmetric (stationary), asymptotically flat There is a horizon in spacetime IMRI can map spacetime ET can see IMRIs out to z 3 See few % deviation quadrupole BH no-hair theorem Test of BH uniqueness theorem Perturbed GW has QNM given by M and S Kerr relation for multipole moments

20 Counting polarization states Polarization tests are qualitative tests A single measurement is good enough to rule the theory out Only two states in GR Plus and cross polarizations Polarization states in a scalar-tensor theory Six different polarization modes Science goals What is the mysterious Dark Energy pulling the Universe apart? CBC as standard candles (sirens) Dark energy and matter interact through gravity Hubble constant Walter Del Pozzo Inference of cosmological parameters from gravitational waves: Applications to second generation interferometers Phys. Rev. D86, (2012)

21 Science goals What powered the Big Bang? Gravitational Waves Can Escape from Earliest Moments of the Big Bang Inflation (Big Bang plus Seconds) neutrinos 1 second Nature 460, (20 August 2009) An upper limit on the stochastic Big Bang plus 380,000 Years gravitational waves light Now gravitational-wave background of cosmological origin The LIGO Scientific Collaboration & Big Bang plus 14 Billion Years The Virgo Collaboration Coherent Consortium T. Bauer Optics A. Bertolini Suspensions N. Van Bakel Linear alignment M. Van Beuzekom Phase camera s J.W. van Holten Theory C. Van Den Broeck CBC Analysis K. Agatsuma (postdoc) Discovery, ET K. van Heijningen (PhD) Discovery R. Jonker (PhD) CW Analysis M. Agathos (PhD) CBC Analysis J. Meidam (PhD) CBC Analysis G. d Ambrosi (PhD) Theory S. Kumar (PhD) Theory P. Groot EM connection (BlackGEM) H.J. Bulten CW Analysis, elisa J. van den Brand Coordinator G. Nelemans Sources, elisa S. Ghosh (postdoc) Joint GW-EM studies S. Shah (PhD) Joint GW-EM studies All members bring in relevant experience

22 Requested resources projects Periodic sources analysis GRID H.J. Bulten (VU), R. Jonker (PhD) Coalescing binaries BNS, BBH C. Van Den Broeck (Nikhef), M. Agathos, J. Meidam, pd1 (3 yr), PhD1 Advanced Virgo upgrade JvdB (VU), A. Bertolini (Nikhef), N. van Bakel (Nikhef), M. van Beuzekom (Nikhef), all PhD and pd Stochastic background theory and analysis JvdB (VU), J.W. van Holten (Nikhef), G. d Ambrosi (PhD), pd3 (3 yr), PhD4 Coalescing binaries Joint GW-EM data analysis G. Nelemans (RU), C. Van Den Broeck (Nikhef), pd2 (3 yr), PhD2 Multi-messenger analysis (BlackGEM, UC binaries) P. Groot (RU), G. Nelemans (RU), H.J. Bulten (VU), PhD3 Einstein Telescope and elisa preparations JvdB (VU), G. Nelemans (RU), A. Bertolini (Nikhef), N. van Bakel (Nikhef), pd4 (2 yr), PhD5 Running budget Annual contribution to Virgo Investment budget: 300 k Third generation: crystalline suspensions, sensor networks 6 year program 6 PhDs, 2 postdocs Investment 300 k Added value of FOM program Ambitious program Combines resources from universities and research institute Strong position at international forefront Program provides focus, collaboration and coherence Timing and urgency: Advanced Virgo and LIGO operational in 2016 Attractive context for advanced research Excellent environment for postdocs, students, guests High quality training Broadening of scientific experience Experimental physics, analysis, GRID computing, astronomy, astrophysics, cosmology, theory Organize national GW community Annual Dutch GW meetings through Nikhef Links to other programs Multi-messenger astroparticle physics (GW-EM, neutrino s)

23 Outreach and social relevance Nikhef spin out company Commercialize Gravitational Physics instrumentation Vibration isolation Sensor networks Outreach publications Science Park Amsterdam Shell Nikhef collaboration agreement Cooperation agreement on PHASE-I.1 Contract signed October 16, 2013 Specifications

24 Ultra-sensitive readout electronics Seismic sensor networks MEMS sensors Bandwidth Hz HTSM SENSEIS Niels van Bakel main PI Nikhef VU University Amsterdam UT EEMCS: CTIT & MESA+ Shell ST Microelectronics InnoSeis Nikhef SAC; April 24, 2014 Jo van den Brand, Nikhef and VU University Amsterdam

25 Backup slides InnoSeis Nikhef spin out company Commercialize Gravitational Physics instrumentation developments See Launched in 2013 Distributed wireless networks Advanced sensors: e.g. accelerometers Mesh network protocols Femtometer positioning Vibration attenuation systems with 10 6 suppression factor Science Park Amsterdam [email protected]

26 MEMS-sensor development Accelerometer prototype Sensitivity 1 ng/rthz Bandwidth Hz Electronics Read-out Force-feedback Sensor network Thousands of sensors around core optics Measure correlations with seismic field Subtraction of gravity gradient noise Actuators in MEMS Seismic sensor demo as etched Predicted sensitivity evolution Advanced detectors only Joint runs: 6 months, 9 m, 1 year, 1 y BNS only (BBH can double rates) Kagra and Indigo will join later See arxiv

27 Primeordial background Quantum fluctuations produce a background GW that is amplified by the background gravitational field Stochastic background Inflation Period of exponential growth of the Universe Phase transitions Forces of Nature splitting off Cosmic strings Topological defects or fundamental (super)strings Predictions quantum gravity theories Pre-Big-Bang cosmology Brane world scenarios Bounce cosmologies Primeordial gravitational waves Primordial stochastic background Wide-band sources Numerous inflation models Approx. Harrison-Zeldovich spectrum Reheating to at least T needed for primordial nucleosynthesis Tensor to scalar ratio r sensitive to V 1/4 For scale invariant spectrum CMB implies that interferometers cannot access SBGW Processes extend over a large range of scale factor Grojean and Servant, Phys. Rev. D75, p , 2007 Flat spectrum Pre-Big Bang Cosmology Cosmic string evolution Topological defects Brane inflation models Peaked sources Phase transitions and reheating Need temperatures of GeV for ET

28 Advanced Detectors and the Stochastic Background ET Old constraint from CMB temperature. Out of reach of advanced detectors by ~5 orders of magnitude Catalog of models: 55 Advanced Detectors and the Stochastic Background ET Rough (to be checked) spectrum corresponding to r = 0.2. Out of reach of advanced detectors by 6-7 orders of magnitude Catalog of models: 56

29 Advanced Detectors and the Stochastic Background If inflation ends with a preheating resonant phase, inflaton energy is efficiently transferred to other particles. Can have significant increase in GW background. Peak depends on energy scale. ET» Easther & Lim, JCAP 0604, 10 GeV 010 (2006) GeV» Easther et al, PRL 99, (2007).» Easther, Nucl. Phys. Proc. Suppl. 194, 33 (2009). Catalog of models: 57 Advanced Detectors and the Stochastic Background Axion-based inflation models include axion-gauge couplings. Gauge backreaction on the inflaton extends inflation. This late inflationary phase ET increases GW production at high frequencies.» Barnaby et al, Phys. Rev. D. 85, (2012).» Cook & Sorbo, Phys. Rev. D85, (2012). Catalog of models: 58

30 Consistency Relation Need Not Hold The consistency relation n t r /8 need not be correct. The tensor spectral index should be measured, and this relation should be confirmed or disproved. Various authors have suggested that the equation of state between inflation and radiation era could be stiff. If so, GW could increase with frequency. Potentially detectable by advanced detectors. Boyle & Buonanno, PRD 78, (2008). 59 Advanced Detectors and the Stochastic Background Cosmic (super)strings models: cusps or kinks moving at relativistic speeds produce bursts of gravitational radiation. Integrating over the whole universe leads to a GW background. Large parameter space, some of it already probed by initial LIGO.» Damour & Vilenkin, PRL 85, 3761 (2000).» Siemens et al, PRL 98, (2007). Catalog of models:» Olmez et al, PRD 81, (2010). 60

31 Advanced Detectors and the Stochastic Background Alternative cosmologies, such as pre-big-bang models, can lead to strong GW backgrounds at high frequencies.» Gasperini & Veneziano, Phys. Rep. 373, 1 (2003).» Buonanno et al, PRD 55, 3330 (1997). Catalog of models: 61 Advanced Detectors and the Stochastic Background Individual neutron star and/or black hole pairs generate chirp GW signals. Integrating over the whole universe (z<6) leads to a GW background. Peak in the LIGO band.» Phinney, ApJ 380, L17 (1991).» Ignatiev et al., MNRAS 327, 531 (2001).» Regimbau & de Freitas Pacheco, ApJ 642, 455 (2006).» Wu et al, Phys. Rev. D 85, (2012). Catalog of models: 62

32 Advanced Detectors and the Stochastic Background Catalog of models: 63 Neutron stars can have a variety of instabilities: r- modes, bar-modes etc. Integrating over the entire universe leads to a GW background.» Owen et al, PRD 58, (1998).» Lai & Shapiro, ApJ 442, 259 (1995).» Regimbau & de Freitas Pacheco,, A&A 376, 381 (2001). Advanced Detectors and the Stochastic Background Catalog of models: Magnetar model: protoneutron stars in very strong magnetic fields (10 16 G) can be distorted (high ellipticity). Integrating over the whole universe leads to a GW background.» Cutler, PRD 66, (2002).» Regimbau & Mandic, CQG 25, (2008).» Dall Osso et al, MNRAS 398, 1869 (2009).» Marassi et al, MNRAS 411, 2549 (2011).» Wu et al, Phys. Rev. D 87, (2013).

33 Conclusions If BICEP-2 result holds up, this is really good news for us! We now know that it is possible to study the physics of these very early times and high energies. This was not a given! Not possible with any lab-based techniques. Physics of inflation could be rich. Many processes do not leave signatures in the CMB, but could be detectable by direct GW observations today. Combine CMB B-mode measurements with interferometric SGWB measurements at different frequencies to disentangle different models, and to really study the physics of inflation. BICEP-2 result is the strongest argument to build the nextgeneration GW detector dedicated to searching for SGWB. This story is just beginning to unfold, and we have an important role to play! Network LISA LIGO, Virgo and GEO exchange data since 2007

34 1 st generation observational results LISA Outreach Intermediair NRC Teleac Radio5 De Volkskrant Kijk Technisch weekblad Civiele Techniek

35 R&D budget breakdown Cryogenic mirror suspension R&D budget breakdown Item Cost estimate (ke) Test facility upgrade Cryocooler 40 Controls 10 Mechanics 20 Electronics 15 Fiber coupled optical sensors 15 Total 100 Components R&D Cryogenic GAS filter 15 Sapphire Williams toggles 15 Alternative design for crystalline vertical springs 20 Sapphire suspension ribbons 50 Silicon flexures 30 Alternative materials for flexures 20 Total 150 Suspension final prototype Cryogenic GAS filter stage and heat links 20 Crystalline suspension structure 20 Sapphire/silicon test mass 10 Total 50 RU involvement Eerste studies van EM-GW synergies voor Virgo (Ghosh et al), laten zien dat EM constraints op afstand of inclinatie kan leiden tot betere parameterschatting Complete studie van EM-GW synergies voor elisa binaries (Shah et al, 4 artikelen) die laten zien dat zo'n studie alleen gedaan kan worden op een *volledige* en *representatieve* set gesimuleerde signalen. Dat betekent dat voor de eerste Virgo studies grootschalig moeten worden uitgebreid Duidelijke rol RU groep in definitie EM follow-up strategie van Virgo/LIGO (Gijs in EM preparation committee, Paul in EM follow-up committee). Bijeenkomst in Amsterdam (1 van de 2 wereldwijd, andere in Chicago) was door ons georganiseerd. Inmiddels >60 aanmeldingen voor MoUs van EM groepen. Design studies voor BlackGEM hebben geleid tot een volwassen ontwerp voor de "ultieme GW follow-up machine" waar door NOVA, RU, NWO, KU Leuven samen 3.2 M Euro voor is uitgetrokken om te realiseren Compact binaries studies van Nelemans (e.g. Nissanke et al. 2012, Littenberg et al. 2013) hebben geleid tot zijn lidmaatschap van elisa consortium board (eerste bijeenkomst na selectie in Amsterdam Jan 2014) en dus uitstekende posities om als NL ook in de toekomst *zichtbaar* aan GW frontline projecten mee te doen. Uitnodiging Living Review Relativity te coordineren over elisa compact binaries science Evt NWO-APP programma noemen? Was er denk ik niet gekomen als dit FOM programma er niet geweest was (al is dat moeilijk aan te tonen)

36 GW Program Management Management Structure Clear structure established to realize Mass and Focus Initial MT composition: GN, CVDB, and JvdB (chair) MT tasks Monitor progress in various scientific activities Allocation of resources (re-discuss annually) Provide steering New scientific developments Note: 1 PhD not allocated Monitor finances Outreach Work towards a national GW community Nikhef has a role here (annual and quarterly meetings) Links to other programs Multi-messenger astroparticle physics (e.g. with KM3Net) Complementarities of GW detectors Difference of 10 4 in wavelength: Like difference between X-rays and IR! Rotating Neutron Stars LISA VIRGO LIGO LISA will see all the compact white-dwarf and neutron-star binaries in the Galaxy (Nelemans)

37 Nikhef: redesign and replace dihedron Eric Hennes Zorg dat je erbij komt Optronica Marinebedrijf Den Helder ET WP1 Infrastructure Infrastructure: big cost items Tunnels, caverns, buildings Vacuum, cryogenics, safety systems Collaborate with industry COB (Amsterdam, October 9, 2008) Saes Getters Italy Demaco Netherlands Input from WG2 & 3 Topology (Albrecht Ruediger) Length of superattenuators Experience Virgo, GEO, Gran Sasso, Kamioka, LIGO, etc.

38 Advanced Virgo: vacuum cryo links LN2 GN2 Fixed 300 K Reinforce rib Tie rod Vacuum + super isolation Isolation vacuum 3.2 mm/m LN2 3.2 mm/m Forces Beam vacuum LISA Summary An efficient, responsive and light structure to support Virgo and promote European collaboration under supervision by national institutions EGO existence relies on Virgo/AdV success The future of GW in Europe depends upon a stronger collaboration between EU countries. EGO may prefigure the required infrastructure. Advanced VIRGO

39 Interferometers sensitivity The horizon (best orientation) for a binary system of two neutron stars is 22 Mpc and of two 10 solar mass black holes is 110 Mpc Activity 2: Signals from inflation and phase transitions Theoretical (astro)particle physics community GW, inflation, string theory, cosmic defects Jan Willem van Holten et al. (Nikhef, Leiden) Provide templates, spectra, etc. G. Koekoek Participate in Virgo LIGO analysis Galluccio et al; Phys. Rev. Lett. 79 (970) LISA