An Indian ad venture in gravitational wave astronomy

An Indian adventure in gravitational wave astronomy

Tarun Souradeep, IUCAA, Pune Spokesperson, IndIGO Consortium

(Indian Initiative in Gravitational-wave Observations)

www.gw-indigo.org

IISER, PuneFeb 4, 2012

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

Space Time as a fabric

Earth follows a “straight path” in the curved space-time caused by sun’s mass !!!

Einstein’s Theory of Gravitationexperimental tests

Mercury’s orbitperihelion 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 GravitationMatter bends light: Gravitational lens

The position of a distant star on the sky shifts due to the gravity of sun

First observational confirmation of Einstein’s theory

Gravitational lens

Einstein Ring Einstein Cross

A nearer galaxy lenses a distant one that happens to be exactly along the same line of sight !!

Four distinct images of gravitationally lensed distant quasar i!!

Interesting Gravitational lens !

Grandest Gravitational lens !

Distant galaxies beyond a cluster lens into arcs ….

Einstein’s General theory of relativity is the most beautiful, as well as,

successful theory of modern physics.

It has matched all experimental tests of Gravitation remarkably well.

Era of precision tests : GP-B,….

Beauty & Precision

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

Gravitational Waves -- travelling space-time ripples

are a fundamental prediction • Existence of GW inferred beyond doubt (Nobel Prize 1993)

• Feeble effect of GW on a Detector strong sources GW Hertz experiment ruled out. Only astrophysical systems involving huge masses and accelerating

very strongly are potential detectable sources of GW signals.

GW Astronomy linkAstrophysical 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 eventsBursts (SN, GRB), mergers, accretion, stellar cannibalism ,…

• Extremely Weak interaction, hence, has been difficult to detect directly But also implies GW carry unscreened & uncontaminated signals

96% universe does not emit Electromagnetic signal!

Pulsar companion

Nobel prizein 1993 !!!

Hulse and Taylor14yr slowdown

of PSR1913+16

Binary pulsar systems emit gravitational waves

Indirect evidence for Gravity waves

Courtesy;: Stan

Whitcomb

14

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

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 andIUCAA in its Data Analysis Aspects.

Neutron star-BH merger

Theoretical developments in classical GR

Principle behind direct Detection of GW

20~ 10 /L m Hz19~ 10 / (Achieved) L m Hz

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

Challenge of Direct Detection

2 L hL

20 2410 10h

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!

Courtesy: Stan Whitcomb

end test mass

beam splittersignal

LIGO Optical Configuration

Laser

MichelsonInterferometer

input test massLight is “recycled” about 50 times

Power Recycled

with Fabry-Perot Arm Cavities

Light bounces back and forth along arms about 100 times

Detecting GW with Laser Interferometer

Difference in distance of Paths Interference of laser light at the detector (Photodiode)

GEO-600Germany

600m

Terrestrial GW observatories

LIGOHanford Washington USA

LIGOLivingstonLouisiana, USA

LIGOLaser Interferometer Gravitational-Wave Observatory

4 kms

4 kms

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.

LISA : Laser Interferometer Space Antenna

A NASA, ESA joint proposal for space based GW Observatory ( expected launch 2011).

GW OBSERVATORY IN SPACE !!

LISA : Laser Interferometer Space AntennaA NASA, ESA joint proposal for space based GW Observatory ( launch

2011). 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

32

Initial LIGO Sensitivity Goal

• Strain sensitivity <3x10-23 1/Hz1/2

at 200 Hz

Sensor Noise» Photon Shot Noise» Residual Gas

Displacement Noise» Seismic motion» Thermal Noise» Radiation Pressure

Era of Advanced GW detectors: 2015

10x sensitivityÞ10x dist reachÞ 1000 volume

Þ >> 1000X event rate

Þ (reach beyondnearest super-

clusters)A Day of Advanced

LIGO Observation >> A year of Initial LIGO

observation

Detector Generation

NS-NS NS-BH BH-BH

Initial LIGO(2002 -2006) 0.02 0.0006 0.0009

Enhanced LIGO(2X Sensitivity)(2009-2010)

0.1 0.04 0.07

Advanced LIGO(10X sensitivity)(2014 - …) 40 10 20

Global Network of GW Observatories improves…

LIGO-LLO: 4km

LIGO-LHO: 2km+ 4kmGEO: 0.6km VIRGO: 3km

future: LCGT 3 kmTAMA/CLIO

1. Detection confidence 2. Duty cycle 3. Source direction 4. Polarization info.

LIGO-India ?

Time delays in millisecondsIndia provides almost largest possible baselines.(Antipodal baseline 42ms)

LIGO-India: … the opportunityScience Gain from Strategic Geographical Relocation

Source localization errorCourtesy:S. Fairhurst Launch of

Gravitational wave Astronomy

vit

GWIC Roadmap Document

Gravitational wave Astronomy :

•Fundamental physics

•Astronomy & Astrophysics

•Cosmology

Scientific PayoffsAdvanced 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

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

Volume Filling factor

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

Sky Coverage: 81%

47.30% 79.00% 53.50%

Directional Precision

0.66 2.02 3.01

Strategic Geographical relocation: science gain

Courtesy: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

LASERAEI, Hannover

Germany

SuspensionGEO, UK

Reflects International cooperationBasic nature of GW Astronomy

Schematic of Advanced LIGOdetectors

Large scale Ultra high Vacuum to be fabricated in India10 mega -litres at nano-torr!!!

Highly Multi-

disciplinaryAstro+

+“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. )

Multi-Institutional,Multi-disciplinary Consortium

1. CMI, Chennai2. Delhi University3. IISER, Kolkata4. IISER, TVM5. IISER, Pune6. IIT Madras (EE)7. IIT Kanpur (EE)8. IUCAA, Pune9. RRCAT, Indore10. IPR, Ahmedabad

Members from• TIFR Mumbai• IISc, Bangalore• RRI, Bangalore• …

Nodal Institutions

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; • 2009-2011:

– Meetings at Kochi, Pune, Shanghai, Perth, Delhi to Define, Reorient and Respond to the Global (GWIC)

strategies for setting up the International GW Network. – Bring together scattered Indian Experimental Expertise;

Individuals & Institutions• March 2011: IndIGO-I Proposal: Participation in LIGO-Australia• May 2011+: LIGO-India..

Note:

•IndIGO was admitted to GWIC in July 2011 : Intl. recognition of the growing community in India.

•IndIGO has been accepted into the LIGO Science Collab. (LSC) : pan-Indian 7 institutes: 15 members: Theory, DA + EXPERIMENTERS ) : Sept. 2011

Data Analysis & Theory

Sanjeev Dhurandhar IUCAABala Iyer RRITarun Souradeep IUCAAAnand Sengupta Delhi Univ.Archana Pai IISER,-TVMSanjit Mitra JPL , IUCAAK G Arun CMIRajesh Nayak IISER-KA. Gopakumar TIFR

IndIGO Consortium

T R Seshadri Delhi University Patrick Dasgupta Delhi UniversitySanjay Jhingan Jamila Milia L. Sriramkumar, IIT MBhim P. Sarma Tezpur Univ . Sanjay Sahay BITS, GoaP Ajith Caltech Sukanta Bose, Wash. U.B. S. Sathyaprakash Cardiff

UniversitySoumya Mohanty UTB,

Brownsville Badri Krishnan Max Planck

AEISatyanarayan Mohapatra UM, Amherst

C. S. Unnikrishnan TIFRG Rajalakshmi TIFRP.K. Gupta RRCATSendhil Raja RRCATS.K. Shukla RRCATRaja Rao RRCAT exxAnil Prabhakar, IIT MShanti Bhattacharya IIT MPradeep Kumar, IIT KAjai Kumar IPRS.K. Bhatt IPRVasant Natarajan IISc.Umakant Rapol IISER

PuneShiva Patil IISER PuneJoy Mitra IISER TvmS. Ghosh IISER KolSupriyo Mitra IISER

Kol

Ranjan Gupta IUCAABhal Chandra Joshi NCRARijuparna Chakraborty Cote d’Azur Rana Adhikari Caltech Suresh Doravari CaltechS. Sunil U. W. Aus.Rahul Kumar U. of GlasgowBiplab Bhawal LIGO exK. Venkat U. WashingtonB. Bhadur U. of Illinois

Instrumentation & Experiment

2009 2010 20110

10

20

30

40

50

60

70

ExpterDATheory

LIGO labs LIGO-

India ?

LIGO-India: unique once-in-a-generation opportunity

Courtesy: Stan Whitcomb 50

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 51

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

Feb 2011 Status• All substrates delivered• Polishing underway• Reflective Coating process

starting up

• Surface specs (/1000) : 100 x best optical telescope

• Surface specs currently available in India for much smaller sizes /20

• Indian industry may now be challenged to achieve on small scale, eg., for TIFR 3m prototype

• Technology for such mirror useful for high optical metrology and other specialized applications

Courtesy: Stan Whitcomb 52

Advanced LIGO Suspensions

• UK designed and contributed test mass suspensions

• Silicate bonds create quasi-monolithic pendulums using ultra-low loss fused silica fibres to suspend interferometer optics

– PendulumQ ~105 ~108

– resonance subHz– suppression 1/f^4

per stage (6 stages)

52

40 kg silica test mass

four stages

“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: unique once-in-a-generation opportunity

LIGO-India : Vacuum structure & engineering

LIGO-India: … the challenges

1. Large scale ultra-high Vacuum enclosureS.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 ).

Courtesy: Stan Whitcomb

Spiral weld UHV beam tubes1.2 m dia: 20 m sections.

Sections butt welded to 200m

UHV Optical tanks to house mirrors : end, beam splitter,…

Expansion Bellows btw 200m beam sections, 1 m gate valves

LIGO Vacuum Equipment

Courtesy: Stan Whitcomb

• Large vacuum chamber fabrication under stringent UHV requirement

• Significant capability upgrade for Indian industry

• Comparable, but smaller UHV chambers in IPR facility

LIGO Beam Tube

• 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 stainless50 km of weld

NO LEAKS !! (10Mega-litres at nano-torr)Major Engg. ChallengeUnprecedented scale

Courtesy: Stan Whitcomb

Constructed > 1 decade back.Operating in Initial LIGO for ~10yrs

Concrete Arches

beamtube transport

beamtube install

girth welding

Beam Tube Construction

Courtesy: Stan Whitcomb

IndIGO - ACIGA meeting 59

LIGO beam tube enclosure

• minimal enclosure

• reinforced concrete

• no services

Courtesy: Stan Whitcomb

Detector Installation using Cleanrooms• Chamber access

through large doors

Courtesy: Stan Whitcomb

Optics Installation Under Cleanroom

Conditions

Courtesy: Stan Whitcomb

• High precision skills

• Low contamination labs & trained manpower for related Indian labs & industry

• Application in other sciences, eg. Material sciences, Space , biotech ,…

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.

• 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)• Attain high technology gains for Indian labs & industries

• 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

Concluding remarks on LIGO India

“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. )

Thank you !!!

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.

• 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

Why is LIGO-India such an Attractive Indian Science Project?