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An Indian adventure in gravitational wave astronomy IISER, Pune Feb 4, 2012 Tarun Souradeep, IUCAA, Pune Spokesperson, IndIGO Consortium (Indian Initiative in Gravitational-wave Observations) www.gw-indigo.org Space Time as a fabric Special Relativity (SR) replaced Absolute space and Absolute Time by flat 4dimensional space-time (the normal three dimensions of space, plus a fourth dimension of time). In 1916, Albert Einstein published his famous Theory of General Relativity, his theory of gravitation consistent with SR, where gravity manifests as a curved 4-diml space-time Theory describes how space-time is affected by mass and also how energy, momentum and stresses affects space-time. Matter tells space-time how to curve, and Space-time tells matter how to move. Space Time as a fabric Earth follows a “straight path” in the curved space-time caused by sun’s mass !!! Einstein’s Theory of Gravitation experimental tests Mercury’s orbit perihelion shifts forward •Mercury's elliptical path around the Sun shifts slightly with each orbit such that its closest point to the Sun (or "perihelion") shifts forward with each pass. •Astronomers had been aware for two centuries of a small flaw in the orbit, as predicted by Newton's laws. •Einstein's predictions exactly matched the observation. Einstein’s Theory of Gravitation Matter bends light: Gravitational lens First observational confirmation of Einstein’s theory The position of a distant star on the sky shifts due to the gravity of sun Gravitational lens Interesting Gravitational lens ! Einstein Ring A nearer galaxy lenses a distant one that happens to be exactly along the same line of sight !! Einstein Cross Four distinct images of gravitationally lensed distant quasar i!! Grandest Gravitational lens ! Distant galaxies beyond a cluster lens into arcs Beauty & Precision Einstein’s General theory of relativity is the most beautiful, as well as, theory of modern physics. It has matched all experimental tests of Gravitation remarkably well. Era of precision tests : GP-B,…. What happens when matter is in motion? Einstein’s Gravity predicts • Matter in motion Space-time ripples fluctuations in space-time curvature that propagate as waves Gravitational waves (GW) • In GR, as in EM, GW travel at the speed of light (i.e., mass-less) , are transverse and have two states of polarization. • The major qualitatively unique prediction beyond Newton’s gravity Begs direct verification !!! A Century long Wait • Einstein’s Gravitation (1916-2011): Beauty : symmetry in fundamental physics –mother of gauge theories & precision : matches all experimental tests till date to high precision GW Astronomy link Gravitational Waves -- travelling space-time ripples Astrophysical systems are sources of copious GW emission: are a fundamental prediction 96% universe does not Electromagnetic signal! •GW emission efficiency ofemit mass for BH mergers) >> • Existence of GW(10% inferred beyond doubt (Nobel Prize 1993) EM radiation via Nuclear fusion (0.05% of mass) • Feeble effectemitted of GW onfrom a Detector strong sources Energy/mass in GW binary >> EM radiation in the lifetime GW Hertz experiment ruled out. • Universe is buzzing with GW signals from cores of astrophysical events Only (SN, astrophysical systems involving huge masses ,… and accelerating Bursts GRB), mergers, accretion, stellar cannibalism very strongly are potential detectable sources of GW signals. • Extremely Weak interaction, hence, has been difficult to detect directly But also implies GW carry unscreened & uncontaminated signals Indirect evidence for Gravity waves Binary pulsar systems emit gravitational waves Pulsar Nobel prize in 1993 !!! Hulse and Taylor 14yr slowdown of PSR1913+16 companion Astrophysical Sources for Terrestrial GW Detectors • Compact binary Coalescence: “chirps” – NS-NS, NS-BH, BH-BH • Supernovas or GRBs: “bursts” – GW signals observed in coincidence with EM or neutrino detectors • Pulsars in our galaxy: “periodic waves” – Rapidly rotating neutron stars – Modes of NS vibration • Cosmological: “stochastic background” ? – Probe back to the Planck time (10-43 s) – Probe phase transitions : window to force unification – Cosmological distribution of Primordial black holes 14 Using GWs to Learn about the Source: an Example Over two decades, RRI involved in computation of inspiral waveforms for compact binaries & their implications and IUCAA in its Data Analysis Aspects. Can determine • Distance from the earth r • Masses of the two bodies • Orbital eccentricity e and orbital inclination i Neutron star-BH merger Theoretical developments in classical GR Principle behind direct Detection of GW L ~ 1019 m / Hz (Achieved) L ~ 1020 m / Hz Detecting GW with Laser Interferometer B A Path A Path B Difference in distance of Path A & B Interference of laser light at the detector (Photodiode) Challenge of Direct Detection Gravitational wave is measured in terms of strain, h (change in length/original length) 2 L L h Gravitational waves are very weak! Expected amplitude of GW signals h 10 Measure changes of 20 10 24 one part in thousand-billion-billion! Detecting GW with Laser Interferometer LIGO Optical Configuration Power Recycled Michelson Interferometer end test mass Light bounces back and forth along arms about 100 times with Fabry-Perot Arm Cavities Light is “recycled” about 50 times input test mass Laser signal beam splitter Difference in distance of Paths Interference of laser light at the detector (Photodiode) Courtesy: Stan Whitcomb Terrestrial GW observatories GEO-600 Germany LIGO 4 kms LIGO Hanford Washington USA Laser Interferometer Gravitational-Wave Observatory 4 kms LIGO Livingston Louisiana, USA Why a GW Observatory in space ? •Terrestrial GW observatories are limited to GW frequencies above 10 Hz due to seismic noise. ( 10 Hz– 2000 Hz.) •Interesting sources abundant at sub-Hertz frequencies (milli-Hz to Hz range) are accessible. •Easier to attain higher sensitivity with longer baselines. GW OBSERVATORY IN SPACE !! LISA : Laser Interferometer Space Antenna A NASA, ESA joint proposal for space based GW Observatory ( expected launch 2011). LISA : Laser Interferometer Space A NASA, ESA joint proposal for space based GW Observatory ( launch 2011). Antenna Frequency range: 10– 4 Hz - 1 Hz A configuration of three `freely falling’ spacecrafts in earth-like orbit linked by optical laser beams working as an interferometer in space The Orbit of LISA The spacecraft are freely falling in the Sun’s field . GW Source for LISA Initial LIGO Sensitivity Goal • Strain sensitivity <3x10-23 1/Hz1/2 at 200 Hz l Sensor Noise » Photon Shot Noise » Residual Gas l Displacement Noise » Seismic motion » Thermal Noise » Radiation Pressure 32 Era of Advanced GW detectors: 2015 Detector Generation Initial LIGO (2002 -2006) Enhanced LIGO (2X Sensitivity) (2009-2010) Advanced LIGO (10X sensitivity) (2014 - …) NS-NS NS-BH 0.02 0.0006 BH-BH 10x sensitivity 10x dist reach 1000 volume >> 1000X 0.0009 event rate (reach beyond 0.1 0.04 nearest0.07 super- clusters) 40 10 A Day of Advanced LIGO Observation >> A year of Initial LIGO 20 observation Global Network of GW Observatories improves… 1. Detection confidence 2. Duty cycle 3. Source direction 4. Polarization info. GEO: 0.6km LIGO-LHO: 2km+ 4km VIRGO: 3km future: LCGT 3 km TAMA/CLIO Time delays in milliseconds India provides almost largest possible baselines. (Antipodal baseline 42ms) LIGO-LLO: 4km LIGO-India ? LIGO-India: … the opportunity Science Gain from Strategic Geographical Relocation Source localization error Courtesy: S. Fairhurst Launch of Gravitational wave Astronomy Gravitational wave Astronomy : vit •Fundamental physics •Astronomy & Astrophysics •Cosmology GWIC Roadmap Document Scientific Payoffs Advanced GW network sensitivity needed to observe GW signals at monthly or even weekly rates. • Direct detection of GW probes strong field regime of gravitation Information about systems in which strong-field and time dependent gravitation dominates, an untested regime including non-linear self-interactions • GW detectors will uncover NEW aspects of the physics Sources at extreme physical conditions (eg., super nuclear density physics), relativistic motions, extreme high density, temperature and magnetic fields. • GW signals propagate un-attenuated weak but clean signal from cores of astrophysical event where EM signal is screened by ionized matter. • Wide range of frequencies Sensitivity over a range of astrophysical scales To capitalize one needs a global array of GW antennas separated by continental distances to pinpoint sources in the sky and extract all the source information encoded in the GW signals LIGO-India: a good idea for GW community ! • Geographical relocation Strategic for GW astronomy – – – – – – Increased event rates (x2-4) by coherent analysis Improved duty cycle Improved Detection confidence Improved Sky Coverage Improved Source Location required for multi-messenger astronomy Improved Determination of the two GW polarizations • Potentially large Indian science user community in the future – Indian demographics: youth dominated – need challenges – Improved UG education system will produce a larger number of students with aspirations looking for frontline research opportunity at home. • Substantial data analysis trained faculty exists in India and Large Data Analysis Center Facilities are being planned under the next five year plan for consolidated IndIGO participation in LSC for Advanced LIGO LIGO-India: … the opportunity Strategic Geographical relocation - the science gain Sky coverage: ‘reach’ /sensitivity in different directions Courtesy: Bernard Schutz LIGO-India: … the opportunity Strategic Geographical relocation: science gain Polarization info Homogeneity of Sky coverage Courtesy: S.Kilmenko & G. Vedovato Strategic Geographical relocation: science gain Network HHLV HILV AHLV Mean horizon distance 1.74 1.57 1.69 Detection Volume 8.98 8.77 8.93 41.00% 54.00% 44.00% Triple Detection Rate(80%) 4.86 5.95 6.06 Triple Detection Rate(95%) 7.81 8.13 8.28 47.30% 79.00% 53.50% 0.66 2.02 3.01 Volume Filling factor Sky Coverage: 81% Directional Courtesy: Precision Bernard Schutz LIGO-India: Attractive Indian megaproject • On Indian Soil with International Cooperation (no competition) • Shared science risks and credits with the International community. • AdvLIGO setup & initial setup risks primarily rests with USA. – AdvLIGO-USA precedes LIGO-India by > 2 years. – Vacuum 10 yr of operation in initial LIGO 2/3 vacuum enclosure + 1/3 detector assembly split (US ‘costing’ : manpower and h/ware costs) – Indian expters can contribute to AdvLIGO-USA : opportunity without primary responsibility • US hardware contribution funded & ready – AdvLIGO largest NSF project funded in USA – LIGO-India needs NSF approval, but not additional funds from USA • Expenditure almost completely in Indian labs & Industry • Very significant Industrial capability upgrade in India. • Well defined training plan Large number of highly trained HRD • Host a major data analysis facility for the entire LIGO network Schematic Optical Design of Advanced LIGO detectors Reflects International cooperation Basic nature of GW Astronomy LASER AEI, Hannover Germany Suspension GEO, UK Highly MultiSchematic of Advanced LIGOdetectors disciplinary ++ Astro “Every single technology they’re touching they’re pushing, and there’s a lot of different technologies they’re touching.” (Beverly Berger, National Science Foundation Program director for gravitational physics. ) Large scale Ultra high Vacuum to be fabricated in India 10 mega -litres at nano-torr!!! Multi-Institutional, Multi-disciplinary Consortium Nodal Institutions 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. CMI, Chennai Delhi University IISER, Kolkata IISER, TVM IISER, Pune IIT Madras (EE) IIT Kanpur (EE) IUCAA, Pune RRCAT, Indore IPR, Ahmedabad Members from • TIFR Mumbai • IISc, Bangalore • RRI, Bangalore • … IndIGO Consortium – a brief history • Dec. 2007 : ICGC2007 @IUCAA: Rana Adhikari’s visit & discussions • 2009: – Australia-India S&T collaboration (Iyer & Blair) Establishing Australia-India collaboration in GW Astronomy – IndIGO Consortium: IUCAA Reunion meeting (Aug 9, 2009) – GW Astronomy Roadmap for India; Note: • 2009-2011: – Meetings at Kochi, Pune, Shanghai, Delhi •IndIGO was admitted to GWICPerth, in July 2011 : Intl. recognition of and the growing in India. to Define, Reorient Respondcommunity to the Global (GWIC) strategies for setting up the International GW Network. •IndIGO has been accepted into the LIGO Science Collab. – Bring together scattered Indian Experimental Expertise; (LSC) : pan-Indian 7 institutes: 15 members: Theory, DA + Individuals & Institutions EXPERIMENTERS ) : Sept. 2011 • March 2011: IndIGO-I Proposal: Participation in LIGO-Australia • May 2011+: LIGO-India.. IndIGO Consortium Data Analysis & Theory Sanjeev Dhurandhar Bala Iyer Tarun Souradeep Anand Sengupta Archana Pai Sanjit Mitra K G Arun Rajesh Nayak A. Gopakumar IUCAA RRI IUCAA Delhi Univ. IISER,-TVM JPL , IUCAA CMI IISER-K TIFR T R Seshadri Patrick Dasgupta Sanjay Jhingan L. Sriramkumar, Bhim P. Sarma Sanjay Sahay P Ajith Sukanta Bose, B. S. Sathyaprakash Soumya Mohanty Badri Krishnan Satyanarayan Mohapatra Delhi University Delhi University Jamila Milia IIT M Tezpur Univ . BITS, Goa Caltech Wash. U. Cardiff University UTB, Brownsville Max Planck AEI UM, Amherst Instrumentation & Experiment 70 C. S. Unnikrishnan TIFR 60 G Rajalakshmi TIFR P.K. Gupta RRCAT 50Raja Sendhil RRCAT S.K. Shukla RRCAT Raja Rao RRCAT exx 40 Anil Prabhakar, IIT M Shanti30 Bhattacharya IIT M Pradeep Kumar, IIT K Ajai Kumar IPR 20 S.K. Bhatt IPR Vasant Natarajan IISc. 10 Umakant Rapol IISER Pune Shiva Patil IISER Pune 0 Joy Mitra IISER Tvm 2009 2010 S. Ghosh IISER Kol Supriyo Mitra IISER Kol Ranjan Gupta IUCAA Bhal Chandra Joshi NCRA Rijuparna Chakraborty Cote d’Azur Rana Adhikari Caltech Suresh Doravari Caltech Expter S. Sunil U. W. Aus. Rahul Kumar DA U. of Glasgow Biplab Bhawal LIGO ex Theory K. Venkat U. Washington B. Bhadur U. of Illinois 2011 LIGO-India: unique once-in-a-generation opportunity LIGO labs LIGO-India ? Advanced LIGO Laser • Designed and contributed by Albert Einstein Institute, Germany • Much higher power (to beat down photon shot noise) – 10W 180W (narrow sub kHz line width) • Better stability – 10x improvement in intensity (nano ppm) and frequency stability (mHz) • Unique globally. Well beyond current Indian capability. Would require years of focused R &D effort. Both power and frequency stability ratings. • AdvLIGO laser has spurred RRCAT to envisage planning development of similar laser capability in the next 5 year plans. IIT M group also interested. • Multiple applications of narrow line width laser : Freq time stand, precision metrology, Quantum key distribution, high sensitivity seismic sensors (geo sc.), coherence LIDAR (atm sc.), …. Courtesy: Stan Whitcomb 50 Advanced LIGO Mirrors • • Larger size – 11 kg 40 kg, 2534 cm • Smaller figure error – 0.7 nm 0.35 nm • Lower absorption – 2 ppm 0.5 ppm • Lower coating thermal noise Surface specs (/1000) : 100 x best optical telescope • Surface specs currently available in India for much smaller sizes /20 Feb 2011 Status • All substrates delivered • Indian industry may now be challenged to achieve on small scale, eg., for TIFR 3m prototype • Polishing underway • Reflective Coating process• Technology for such mirror useful for high optical starting up metrology and other specialized applications Courtesy: Stan Whitcomb 51 Advanced LIGO Suspensions • UK designed and contributed test mass suspensions • Silicate bonds create quasimonolithic pendulums using ultra-low loss fused silica fibres to suspend interferometer optics – Pendulum Q ~105 ~108 – resonance subHz four stages – suppression 1/f^4 per stage (6 stages) 40 kg silica test mass Courtesy: Stan Whitcomb 52 52 LIGO-India: unique once-in-a-generation opportunity “Quantum measurements” to improve further via squeezed light: • Potential technology spin-offs will impact quantum computing and quantum key distribution (QKD) for secure communications. (IITM approached by ITI for QKD development.) • New ground for optics and communication technology in India • High Potential to draw the best Indian UG students, typically interested in theoretical physics, into experimental science !!! LIGO-India: … the challenges LIGO-India : Vacuum structure & engineering 1. Large scale ultra-high Vacuum enclosure S.K. Shukla (RRCAT), A.S. Raja Rao (ex RRCAT), S. Bhatt (IPR), Ajai Kumar (IPR) To be fabricated by Industry with designs from LIGO. A pumped volume of 10000m3 (10Mega-litres), evacuated to an ultra high vacuum of nano-torr (10-9 torr ). Spiral weld UHV beam tubes 1.2 m dia: 20 m sections. Sections butt welded to 200m Expansion Bellows btw 200m beam sections, 1 m gate valves UHV Optical tanks to house mirrors : end, beam splitter,… Courtesy: Stan Whitcomb LIGO Vacuum Equipment • Large vacuum chamber fabrication under stringent UHV requirement • Significant capability upgrade for Indian industry • Comparable, but smaller UHV chambers in IPR facility Courtesy: Stan Whitcomb LIGO Beam Tube Constructed > 1 decade back. Operating in Initial LIGO for ~10yrs • LIGO beam tube under construction in January 1998 • 16 m spiral welded sections • girth welded in portable clean room in the field 1.2 m diameter - 3mm stainless 50 km of weld NO LEAKS !! (10Mega-litres at nano-torr) Major Engg. Challenge Unprecedented scale Courtesy: Stan Whitcomb Beam Tube Construction beamtube transport beamtube install Concrete Arches girth welding Courtesy: Stan Whitcomb LIGO beam tube enclosure • minimal enclosure • reinforced concrete • no services Courtesy: Stan Whitcomb IndIGO - ACIGA meeting 59 • Detector Installation using Cleanrooms Chamber access through large doors Courtesy: Stan Whitcomb Optics Installation Under Cleanroom Conditions •High precision skills • Low contamination labs & trained manpower for related Indian labs & industry • Application in other sciences, eg. Material sciences, Space , biotech ,… Courtesy: Stan Whitcomb Science Payoffs New Astronomy, New Astrophysics, New Cosmology, New Physics ” A New Window ushers a New Era of Exploration in Physics & Astronomy” – – – – – Testing Einstein’s GR in strong and time-varying fields Testing Black Hole phenomena Understanding nuclear matter by Neutron star EOS Neutron star coalescence events Understanding most energetic cosmic events ..Supernovae, Gamma-ray bursts, LMXB’s, Magnetars – – – – New cosmology..SMBHB’s as standard sirens..EOS of Dark Energy Phase transition related to fundamental unification of forces Multi-messenger astronomy The Unexpected !!!!! Technology Payoffs • Lasers and optics..Purest laser light..Low phase noise, excellent beam quality, high single frequency power • Applications in precision metrology, medicine, micro-machining • Coherent laser radar and strain sensors for earthquake prediction and other precision metrology • Surface accuracy of mirrors 100 times better than telescope mirrors..Ultra-high reflective coatings : New technology for other fields • Vibration Isolation and suspension..Applications for mineral prospecting • Squeezing and challenging “quantum limits” in measurements. • Ultra-high vacuum system 10^-9 torr (1picomHg). Beyond best in the region. The largest UHV system will provide industry a challenge and experience. • Computation Challenges: Cloud computing, Grid computing, new hardware and software tools for computational innovation. Concluding remarks on LIGO India Thank you !!! • Home ground advantage !!! Once in a generation opportunity • Threshold of discovery and launch of a new observational window in human history!! Century after Einstein GR, 40 yrs of Herculean global effort • Cooperative, not competitive science • India at the forefront of GW science with 2nd generation of detectors: Intl. shared science risks and credit • Low project risk: commit to established tech. yet are able to take on challenges of advLIGO (opportunity without primary responsibility) “Every high singletechnology technology gains they’refor touching pushing, and there’s • Attain Indian they’re labs & industries a lot of different technologies they’re touching.” (Beverly Berger, National Science Foundation Program director for gravitational physics. ) • India pays true tribute to fulfilling Chandrasekhar’s legacy: ”Astronomy is the natural home of general relativity” An unique once-in-a-generation opportunity for India. India could play a key role in Intl. Science by hosting LIGO-India. Deserves National mega-science project status Rewards and spinoffs Detection of GW is the epitome of breakthrough science!!! • LIGO-India India could become a partner in international science of Nobel Prize significance • GW detection is an instrument technology intensive field pushing frontiers simultaneously in a number of fields like lasers and photonics. Impact allied areas and smart industries. • The imperative need to work closely with industry and other end users will lead to spinoffs as GW scientists further develop optical sensor technology. • Presence of LIGO-India will lead to pushing technologies and greater innovation in the future. • Increase number of research groups performing at world class levels and produce skilled researchers. Why is LIGO-India such an Attractive Indian Science Project? • India leads high visibility, fundamental science expt. that has huge (international) public appeal !!! • Indian academia and industry would be working together • The project provides high-technology goals that sharpen & showcase the abilities of Indian institutions and industry. • The project will lead to significant human resources development (HRD@home) in academic, technical and industrial spheres. Produce highly skilled S & T workforce for India • Jobs at all levels for region hosting LIGO-India. Proximity to world class science