Detecting Einstein’s Elusive Waves Opening a New Window to the Universe LIGO-India: An Indo-US joint mega-project concept proposal IndIGO Consortium (Indian Initiative in Gravitational-wave Observations) Version: pI_v1 Jun 20, 2011 : TS

Beauty & Precision

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 of Waiting Almost 100 years since Einstein predicted GW but no direct experimental confirmation (a la Hertz for Maxwell EM theory) Two Fundamental Difference between GR and EM - Weakness of Gravitation relative to EM (10^-39) -Spin two nature of Gravitation vs Spin one of EM that forbids dipole radiation in GR Low efficiency for conversion of mechanical energy to GW. Feeble effects of GW on a Detector GW Hertz experiment ruled out. Only astrophysical systems involving huge masses and accelerating very strongly are potential detectable sources of GW signals.

Astrophysical systems are sources of copious GW emission: GW emission efficiency (10% of mass for BH mergers) >> EM radiation via Nuclear fusion (0.05% of mass) Energy/mass emitted in GW from binary >> EM radiation in the lifetime Universe is buzzing with GW signals from cores of astrophysical events Bursts (SN, GRB), mergers, accretion, stellar cannibalism,… Extremely Weak interaction, hence, has been difficult to detect directly But also implies GW carry unscreened & uncontaminated signals GW  Astronomy link

Pulsar companion GW from Binary Neutron stars

leads to loss of orbital energy period speeds up 14 sec from measured to ~50 msec accuracy deviation grows quadratically with time Binary pulsar systems emit gravitational waves Hulse and Taylor Results for PSR Indirect evidence for Gravity waves Nobel prize in 1993 !!!

Courtesy;: Stan Whitcomb 8 Astrophysical Sources for Terrestrial GW Detectors Compact binary inspiral:“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 ( s) – Probe phase transitions : window to force unification – Cosmological distribution of Primordial black holes

vit GWIC Roadmap Document Gravitational wave Astronomy : Synergy with other major Astronomy projects SKA -Radio : Pulsars timing, X-ray satellite (AstroSat) : High energy physics Gamma ray observatory: Thirty Meter Telescope: Resolving multiple AGNs, gamma ray follow-up after GW trigger,… LSST: Astro-transients with GW triggers. INO: neutrino signals

Challenge of Direct Detection Gravitational wave is measured in terms of strain, h (change in length/original length ) Expected amplitude of GW signals Measure changes of one part in thousand-billion-billion! Gravitational waves are very weak!

Principle behind Detection of GW

Effect of GW on a ring of test masses Interferometer mirrors as test masses

Using GWs to Learn about the Source: an Example Distance from the earth r Masses of the two bodies Orbital eccentricity e and orbital inclination i Can determine Over two decades, RRI involved in computation of inspiral waveforms for compact binaries & their implications and IUCAA in its Data Analysis Aspects.

Era of Advanced LIGO detectors: x sensitivity  10x reach  1000 volume >> 1000 event rate ( reach beyond nearest super- clusters ) A Day of Advanced LIGO Observation >> A year of Initial LIGO

Expected Annual Coalescence Event Rates Detector Generation NS-NSNS-BHBH-BH Initial LIGO ( ) Enhanced LIGO (2X Sensitivity) ( ) Advanced LIGO (10X sensitivity) ( …) In a 95% confidence interval, rates uncertain by 3 orders of magnitude NS-NS ( ); NS-BH ( ) ; BH-BH ( ) yr^-1 Based on Extrapolations from observed Binary Pulsars, Stellar birth rate estimates, Population Synthesis models. Rates quoted below are mean of the distribution.

GW Astronomy with Intl. Network of GW Observatories GW Astronomy with Intl. Network of GW Observatories LIGO-LLO: 4km LIGO-LHO: 2km+ 4km GEO: 0.6km VIRGO: 3km LCGT 3 km TAMA/CLIO LIGO-Australia? 1. Detection confidence 2. Duty cycle 3. Source direction 4. Polarization info. LIGO-India ?

LIGO-India: … the opportunity Strategic Geographical relocation: science gain Source localization error Original plan 2 +1 LIGO USA+ Virgo LIGO-India plan 1+1 LIGO USA+ Virgo+ LIGO India LIGO-Aus plan 1+1 LIGO USA+ Virgo+ LIGO Aus

LIGO-India: … the opportunity Polarization info Homogeneity of Sky coverage Courtesy: B. Schutz Strategic Geographical relocation: science gain

LIGO-India: … the opportunity Sky coverage : Synthesized Network beam (antenna power) Courtesy: B. Schutz Strategic Geographical relocation: science gain

LIGO-India: … the opportunity Sky coverage: ‘reach’ /sensitivity in different directions Courtesy: B. Schutz Strategic Geographical relocation: science gain

21 From the GWIC Strategic Roadmap for GW Science with thirty year horizon (2007) … the first priority for ground-based gravitational wave detector development is to expand the network, adding further detectors with appropriately chosen intercontinental baselines and orientations to maximize the ability to extract source information. ….Possibilities for a detector in India (IndIGO) are being studied..

Indo-Aus.Meeting, Delhi, Feb 2011

Indian Gravitational wave legacy Two decades of Indian contribution to the international effort for detecting GW on two significant fronts : Seminal contributions to source modeling at RRI [Bala Iyer] and to GW data analysis at IUCAA [Sanjeev Dhurandhar] which has been internationally recognized RRI: Indo-French collaboration for two decades to compute high accuracy waveforms for in-spiraling compact binaries from which the GW templates used in LIGO and Virgo are constructed. IUCAA: Designing efficient data analysis algorithms involving advanced mathematical concepts. Notable contributions include the search for binary in-spirals, hierarchical methods, coherent search with a network of detectors and the radiometric search for stochastic gravitational waves. IUCAA has collaborated with most international GW detector groups and has been a member of the LIGO Scientific Collaboration. At IUCAA, Tarun Souradeep with expertise in CMB data and Planck has worked to create a bridge between CMB and GW data analysis challenges.

Indian Gravitational wave strengths Very good students and post-docs produced from these activities. * Leaders in GW research abroad [Sathyaprakash, Bose, Mohanty] (3) *Recently returned to faculty positions at premier Indian institutions (6) [Gopakumar, Archana Pai, Rajesh Nayak, Anand Sengupta, K.G. Arun, Sanjit Mitra, P. Ajith?] – Gopakumar (?) and Arun (?) : PN modeling, dynamics of CB, Ap and cosmological implications of parameter estimation – Rajesh Nayak (UTB  IISER K), Archana Pai (AEI  IISER T), Anand Sengupta (LIGO, Caltech  Delhi), Sanjit Mitra (JPL  IUCAA ): Extensive experience on single and multi- detector detection, hierarchical techniques, noise characterisation schemes, veto techniques for GW transients, bursts, continuous and stochastic sources, radiometric methods, … – P. Ajith (Caltech, LIGO/TAPIR  ? ) …… – Sukanta Bose (Faculty UW, USA  ?) Strong Indian presences in GW Astronomy with Global detector network  broad international collaboration is the norm  relatively easy to get people back. Close interactions with Rana Adhikari (Caltech), B.S. Sathyaprakash (Cardiff), Sukanta Bose ( WU, Pullman), Soumya Mohanty (UTB), Badri Krishnan ( AEI) … Very supportive Intl community reflected in Intl Advisory committee of IndIGO

High precision and Large experiment in India C.S. Unnikrishnan (TIFR) : involved in high precision experiments and tests – Test gravitation using most sensitive torsional balances and optical sensors. – Techniques related to precision laser spectroscopy, electronic locking, stabilization. – Ex students from this activity G.Rajalakshmi (TIFR, 3m prototype) Suresh Doravari (Caltech 40m) Groups at BARC and RRCAT : involved in LHC – providing a variety of components and subsystems like precision magnet positioning stand jacks, superconducting correcting magnets, quench heater protection supplies and skilled manpower support for magnetic tests and measurement and help in commissioning LHC subsystems. S.K. Shukla at RRCAT on INDUS: UHV experience. S.B. Bhatt and Ajai Kumar at IPR on Aditya: UHV experience. A.S. Raja Rao (ex RRCAT) : consultant on UHV Sendhil Raja (RRCAT) : – Optical system design – laser based instrumentation, optical metrology – Large aperture optics, diffractive optics, micro-optic system design. Anil Prabhakar IITM and Pradeep Kumar IITK (EE dept s) – Photonics, Fiber optics and communications – Characterization and testing of optical components and instruments for use in India.. Rijuparna Chakraborty (Observatoire de la Cote d'Azur)..Adaptive Optics.. – Under consideration for postdoc in LIGO or Virgo….

Multi-Institutional, Multi-disciplinary Consortium (2009) 1.CMI, Chennai 2.Delhi University 3.IISER Kolkata 4.IISER Trivandrum 5.IIT Madras (EE) 6.IIT Kanpur (EE) 7.IUCAA 8.RRCAT 9.TIFR RRI IPR, Bhatt Jamia Milia Islamia Tezpur Univ

The IndIGO Consortium Data Analysis & Theory 1.Sanjeev Dhurandhar IUCAA 2.Bala Iyer RRI 3.Tarun Souradeep IUCAA 4.Anand Sengupta Delhi University 5.Archana Pai IISER, Thiruvananthapuram 6.Sanjit Mitra JPL, IUCAA 7.K G Arun Chennai Math. Inst., Chennai 8.Rajesh Nayak IISER, Kolkata 9.A. Gopakumar TIFR, Mumbai 10.T R Seshadri Delhi University 11.Patrick Dasgupta Delhi University 12.Sanjay Jhingan Jamila Milia Islamia, Delhi 13.L. Sriramkumar, Phys., IIT M 14.Bhim P. Sarma Tezpur Univ. 15.P Ajith Caltech, USA 16.Sukanta Bose, Wash. U., USA 17.B. S. Sathyaprakash Cardiff University, UK 18. Soumya Mohanty UTB, Brownsville, USA 19.Badri Krishnan Max Planck AEI, Germany Instrumentation & Experiment 1.C. S. Unnikrishnan TIFR, Mumbai 2.G Rajalakshmi TIFR, Mumbai 3.P.K. GuptaRRCAT, Indore 4.Sendhil RajaRRCAT, Indore 5.S.K. Shukla RRCAT, Indore 6.Raja Rao ex RRCAT, Consultant 7.Anil Prabhakar, EE, IIT M 8.Pradeep Kumar, EE, IIT K 9.Ajai Kumar IPR, Bhatt 10.S.K. Bhatt IPR, Bhatt 11.Ranjan Gupta IUCAA, Pune 12.Rijuparna Chakraborty, Cote d’Azur, Grasse 13.Rana Adhikari Caltech, USA 14.Suresh Doravari Caltech, USA 15.Biplab Bhawal (ex LIGO) IndIGO Council 1.Bala Iyer ( Chair) RRI, Bangalore 2.Sanjeev Dhurandhar (Science) IUCAA, Pune 3.C. S. Unnikrishnan (Experiment) TIFR, Mumbai 4.Tarun Souradeep (Spokesperson) IUCAA, Pune

23 July 2011 Dear Bala: to present the GWIC membership application for IndIGO. you have made a strong case for membership…… I am writing to invite you to attend the next meeting of the Gravitational Wave International Committee (GWIC) to present the GWIC membership application for IndIGO. This in-person meeting will give you the opportunity to interact with the members of GWIC and to answer their questions about the status and plans for IndIGO. Jim Hough (the GWIC Chair) and I have reviewed your application and believe that you have made a strong case for membership……

IndIGO: the goals & roles Provide a common umbrella to initiate and expand GW related experimental activity and training new manpower – 3m prototype detector in TIFR (funded) - Unnikrishnan – Laser expt. RRCAT, IIT M, IIT K - Sendhil Raja, Anil Prabhakar, Pradeep Kumar – Ultra High Vacuum & controls at RRCAT, IPR, BARC, ISRO, …. Shukla, Raja Rao, Bhatt, – UG summer internship at National & International GW labs & observatories. – Postgraduate IndIGO schools, specialized courses,… Consolidated IndIGO membership of LIGO Scientific Collaboration in Advanced LIGO Proposal to create a Tier-2 data centre for LIGO Scientific Collaboration in IUCAA IUSSTF Indo-US joint Centre at IUCAA with Caltech (funded) Major experimental science initiative in GW astronomy  Earlier Plan: Partner in LIGO-Australia (a diminishing possibility) – Advanced LIGO hardware for 1 detector to be shipped to Australia at the Gingin site, near Perth. NSF approval – Australia and International partners find funds (equiv to half the detector cost ~$140M and 10 year running cost ~$60M) within a year. – Indian partnership at 15% of Australian cost with full data rights.  Today: LIGO-India (Letter from LIGO Labs) – Advanced LIGO hardware for 1 detector to be shipped to India. – India provides suitable site and infrastructure to house the GW observatory – Site, two 4km arm length high vacuum tubes in L configuration – Indian cost ~ Rs 1000Cr The Science & technology benefit of LIGO-India is transformational

IndIGO 3m Prototype Detector Funded by TIFR Mumbai on compus (2010) PI: C. S. Unnikrishnan (Cost ~ INR 2.5 crore)

 Primary Science: Online Coherent search for GW signal from binary mergers using data from global detector network Coherent  5 x event rate (8-> 40 /yrs) [chk numbers]  Role of IndIGO data centre  Large Tier-2 data/compute centre for archival of GWdata and analysis  Bring together data-analysts within the Indian gravity wave community.  Puts IndIGO on the global map for international collaboration with LIGO Science Collab. wide facility. Part of LSC participation from IndIGO  Large University sector participation via IUCAA 200 Tflops peak capability (by 2014) Storage: 4x100TB per year per interferometer. Network: gigabit+ backbone, National Knowledge Network Gigabit dedicatedlink to LIGO lab Caltech 20 Tf 200 Tb funded IUCAA : ready Mid 2012 IndIGO Data Anand Sengupta, DU, IndIGO

Indo-US centre for Gravitational Physics and Astronomy Centre of the Indo-US Science and Technology Forum (IUSSTF) Exchange program to fund mutual visits and facilitate interaction. Nodal centres: IUCAA, India & Caltech, US. Institutions: Indian: IUCAA, TIFR, IISER, DU, CMI - PI: Tarun Souradeep, IUCAA US: Caltech, WSU - PI: Rana Adhikari, Caltech APPROVED for funding (Dec 2010)

Dear Prof. Kasturirangan, 1 June 2011 a concept proposal on behalf of LIGO Laboratory (USA) and the IndIGO Consortium, for a Joint Partnership venture to set up an Advanced gravitational wave detector at a suitable Indian site. The key idea is to utilize the high technology instrument components already fabricated for one of the three Advanced LIGO interferometers in an infrastructure provided by India that matches that of the US Advanced LIGO observatories. In its road-map with a thirty year horizon, the Gravitational Wave International Committee (a working unit of the International Union of Pure and Applied Physics, IUPAP) has identified the expansion of the global network of gravitational wave interferometer observatories as a high priority for maximizing the scientific potential of gravitational wave observations. We are writing to you to put forward a concept proposal on behalf of LIGO Laboratory (USA) and the IndIGO Consortium, for a Joint Partnership venture to set up an Advanced gravitational wave detector at a suitable Indian site. In what follows this project is referred to as LIGO-India. The key idea is to utilize the high technology instrument components already fabricated for one of the three Advanced LIGO interferometers in an infrastructure provided by India that matches that of the US Advanced LIGO observatories. operational early in the lifetime of the advanced versions of gravitational wave observatories India would be unique among nations leading the scientific exploration of this new window on the universea fraction of the total cost of independently establishing a fully-equipped and advanced observatory. LIGO-India could be operational early in the lifetime of the advanced versions of gravitational wave observatories now being installed the US (LIGO) and in Europe (Virgo and GEO) and would be of great value not only to the gravitational wave community, but to broader physics and astronomy research by launching an era of gravitational wave astronomy, including, the fundamental first direct detection of gravitational waves. As the southernmost member observatory of the global array of gravitational wave detectors, India would be unique among nations leading the scientific exploration of this new window on the universe. The present proposal promises to achieve this at a fraction of the total cost of independently establishing a fully-equipped and advanced observatory. It also offers technology that was developed over two decades of highly challenging global R&D effort that preceded the success of Initial LIGO gravitational wave detectors and the design of their advanced version. LIGO-India from LIGO Thank you !!!

END

Committees: National Steering Committee: Kailash Rustagi (IIT, Mumbai) [Chair] Bala Iyer (RRI) [Coordinator] Sanjeev Dhurandhar (IUCAA) [Co-Coordinator] D.D. Bhawalkar (Quantalase, Indore)[Advisor] P.K. Kaw (IPR) Ajit Kembhavi (IUCAA) P.D. Gupta (RRCAT) J.V. Narlikar (IUCAA) G. Srinivasan International Advisory Committee Abhay Ashtekar (Penn SU)[ Chair] Rana Adhikari (LIGO, Caltech, USA) David Blair (ACIGA &UWA, Australia) Adalberto Giazotto (Virgo, Italy) P.D. Gupta (Director, RRCAT, India) James Hough (GEO ; Glasgow, UK)[GWIC Chair] Kazuaki Kuroda (LCGT, Japan) Harald Lueck (GEO, Germany) Nary Man (Virgo, France) Jay Marx (LIGO, Director, USA) David McClelland (ACIGA&ANU, Australia) Jesper Munch (Chair, ACIGA, Australia) B.S. Sathyaprakash (GEO, Cardiff Univ, UK) Bernard F. Schutz (GEO, Director AEI, Germany) Jean-Yves Vinet (Virgo, France) Stan Whitcomb (LIGO, Caltech, USA) IndIGO Advisory Structure Program Management Committee: C S Unnikrishnan (TIFR, Mumbai), [Chair] Bala R Iyer (RRI, Bangalore), [Coordinator] Sanjeev Dhurandhar (IUCAA, Pune) [Co-cordinator] Tarun Souradeep (IUCAA, Pune) Bhal Chandra Joshi (NCRA, Pune) P Sreekumar (ISAC, Bangalore) P K Gupta (RRCAT, Indore) S K Shukla (RRCAT, Indore) Sendhil Raja (RRCAT, Indore)]

NetworkHHLVHILVAHLV Mean horizon distance Detection Volume Volume Filling factor 41.00%54.00%44.00% Triple Detection Rate(80%) Triple Detection Rate(95%) Sky Coverage: 81% 47.30%79.00%53.50% Directional Precision Strategic Geographical relocation: science gain

Special Relativity (SR) replaced Absolute space and Absolute Time by flat 4- dimensional 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 !!!

What happens when matter is in motion?

Concluding remarks A century after Einstein’s prediction, we are on the threshold of a new era of GW astronomy following GW detection. Involved four decades of very innovative and Herculean struggle at the edge of science & technology First generation detectors like Initial LIGO and Virgo have achieved design sensitivity  Experimental field is mature Broken new ground in optical sensitivity, pushed technology and proved technique. Second generation detectors are starting installation and expected to expand the “Science reach” by factor of 1000 Cooperative science model: A worldwide network is starting to come on line and the ground work has been laid for operation as a integrated system. Low project risk : A compelling Science case with shared science risk, a proven design for India’s share of task (other part : opportunity w/o responsibility) National mega-science initiative: Need strong multi-institutional support to bring together capable scientists & technologist in India An unique once-in-a-generation opportunity for India. India could play a key role in Intl. Science by hosting LIGO-India.

… Concluding remarks A GREAT opportunity but a very sharp deadline of 31 Mar If we cannot act quickly the possibility will close. Conditions laid out in the Request Doc of LIGO- Lab will need to be ready for LIGO-Lab examination latest by Dec 2011 so that in turn LIGO-Lab can make a case with NSF by Jan Of all the large scientific projects out there, this one is pushing the greatest number of technologies the hardest. “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. ) One is left speculating if by the centenary of General Relativity in 2015, the first discovery of Gravitational waves would be from a Binary Black Hole system, and Chandrasekhar would be doubly right about Astronomy being the natural home of general relativity. Thank you !!!

Detecting GW with Laser Interferometer Difference in distance of Path A & B  Interference of laser light at the detector (Photodiode) Path A Path B A B