Gravitational Wave Detection of Astrophysical Sources Barry C Gravitational Wave Detection of Astrophysical Sources Barry C. Barish Caltech Neutrino Telescope Venice 24-Feb-05 Crab Pulsar LIGO-xxx

gravitational radiation Einstein’s Theory of Gravitation a necessary consequence of Special Relativity with its finite speed for information transfer gravitational waves come from the acceleration of masses and propagate away from their sources as a space-time warpage at the speed of light gravitational radiation binary inspiral of compact objects 24-Feb-05 Venice Neutrino Telescope

Einstein’s Theory of Gravitation gravitational waves Using Minkowski metric, the information about space-time curvature is contained in the metric as an added term, hmn. In the weak field limit, the equation can be described with linear equations. If the choice of gauge is the transverse traceless gauge the formulation becomes a familiar wave equation The strain hmn takes the form of a plane wave propagating at the speed of light (c). Since gravity is spin 2, the waves have two components, but rotated by 450 instead of 900 from each other. 24-Feb-05 Venice Neutrino Telescope

Detection of Gravitational Waves Gravitational Wave Astrophysical Source Terrestrial detectors Virgo, LIGO, TAMA, GEO AIGO Detectors in space LISA 24-Feb-05 Venice Neutrino Telescope

Gravitational Waves in Space LISA Three spacecraft, each with a Y-shaped payload, form an equilateral triangle with sides 5 million km in length. 24-Feb-05 Venice Neutrino Telescope

Venice Neutrino Telescope LISA The diagram shows the sensitivity bands for LISA and LIGO 24-Feb-05 Venice Neutrino Telescope

Venice Neutrino Telescope Detecting a passing wave …. Free masses 24-Feb-05 Venice Neutrino Telescope

Venice Neutrino Telescope Detecting a passing wave …. Interferometer 24-Feb-05 Venice Neutrino Telescope

Interferometer Concept Laser used to measure relative lengths of two orthogonal arms Arms in LIGO are 4km Measure difference in length to one part in 1021 or 10-18 meters …causing the interference pattern to change at the photodiode As a wave passes, the arm lengths change in different ways…. Suspended Masses 24-Feb-05 Venice Neutrino Telescope

Simultaneous Detection 3002 km (L/c = 10 ms) Hanford Observatory MIT Caltech Livingston Observatory 24-Feb-05 Venice Neutrino Telescope

LIGO Livingston Observatory 24-Feb-05 Venice Neutrino Telescope

LIGO Hanford Observatory 24-Feb-05 Venice Neutrino Telescope

LIGO Goals and Priorities Interferometer performance Integrate commissioning and data taking Obtain one year of integrated data at h = 10-21 by 2008 Physics results from LIGO I Initial upper limit results by early 2003 First search to begin in 2005 Reach LIGO I goals by 2008 Advanced LIGO Advanced LIGO approved at NSF / NSB (Nov 04) for ($185M) Included in the Bush Administration’s budget plan released Feb 05 for 2008 start 24-Feb-05 Venice Neutrino Telescope

Venice Neutrino Telescope Lock Acquisition 24-Feb-05 Venice Neutrino Telescope

What Limits LIGO Sensitivity? Seismic noise limits low frequencies Thermal Noise limits middle frequencies Quantum nature of light (Shot Noise) limits high frequencies Technical issues - alignment, electronics, acoustics, etc limit us before we reach these design goals 24-Feb-05 Venice Neutrino Telescope

Venice Neutrino Telescope Evolution of LIGO Sensitivity 24-Feb-05 Venice Neutrino Telescope

From electronic logbook Detecting Earthquakes From electronic logbook 2-Jan-02 An earthquake occurred, starting at UTC 17:38. 24-Feb-05 Venice Neutrino Telescope

Detect the Earth Tide from the Sun and Moon 24-Feb-05 Venice Neutrino Telescope

Venice Neutrino Telescope Science Runs A Measure of Progress Virgo Cluster Andromeda Milky Way NN Binary Inspiral Range E8 ~ 5 kpc S1 ~ 100 kpc S2 ~ 0.9Mpc S3 ~ 3 Mpc Design ~ 14 Mpc 24-Feb-05 Venice Neutrino Telescope

Astrophysical Sources Compact binary inspiral: “chirps” NS-NS waveforms are well described BH-BH need better waveforms search technique: matched templates Supernovae / GRBs: “bursts” burst signals in coincidence with signals in electromagnetic radiation prompt alarm (~ one hour) with neutrino detectors Pulsars in our galaxy: “periodic” search for observed neutron stars (frequency, doppler shift) all sky search (computing challenge) r-modes Cosmological Signals “stochastic background” 24-Feb-05 Venice Neutrino Telescope

Detection of Periodic Sources Pulsars in our galaxy: “periodic” search for observed neutron stars all sky search (computing challenge) r-modes Frequency modulation of signal due to Earth’s motion relative to the Solar System Barycenter, intrinsic frequency changes. Amplitude modulation due to the detector’s antenna pattern. 24-Feb-05 Venice Neutrino Telescope

Venice Neutrino Telescope Two Search Methods Frequency domain Best suited for large parameter space searches Maximum likelihood detection method + Frequentist approach Time domain Best suited to target known objects, even if phase evolution is complicated Bayesian approach Early science runs --- use both pipelines for the same search for cross-checking and validation 24-Feb-05 Venice Neutrino Telescope

Directed Pulsar Limits on Strain J1939+2134 S2 J1910 – 5959D: h0 = 1.7 x 10-24 Crab pulsar h95 1 PDF strain Marginalized Bayesian PDF for h Red dots: pulsars are in globular clusters - cluster dynamics hide intrinsic spin-down properties Blue dots: field pulsars for which spin-downs are known 24-Feb-05 Venice Neutrino Telescope

Directed Pulsar Search 28 Radio Sources 24-Feb-05 Venice Neutrino Telescope

NO gravitational waves Upper limit on pulsar ellipticity moment of inertia tensor gravitational ellipticity of pulsar NEW RESULT 28 known pulsars NO gravitational waves e < 10-5 – 10-6 (no mountains > 10 cm R . . 24-Feb-05 Venice Neutrino Telescope

Blue dots: field pulsars for which spin-downs are known Ellipticity Limits Best upper-limits: J1910 – 5959D: h0 < 1.7 x 10-24 J2124 – 3358:  < 4.5 x 10-6 How far are S2 results from spin-down limit? Crab: ~ 30X EM spin-down upper-limits LIGO upper-limits from hmax J1939+2134 S1 S2 Red dots: pulsars are in globular clusters - cluster dynamics hide intrinsic spin-down properties Blue dots: field pulsars for which spin-downs are known 24-Feb-05 Venice Neutrino Telescope

Detection of Periodic Sources Signature of gravitational wave Pulsars Frequency modulation of signal due to Earth’s motion relative to the Solar System Barycenter, intrinsic frequency changes. Amplitude modulation due to the detector’s antenna pattern. ALL SKY SEARCH enormous computing challenge 24-Feb-05 Venice Neutrino Telescope

Venice Neutrino Telescope Einstein@Home A maximum-sensitivity all-sky search for pulsars in LIGO data requires more computer resources than exist on the planet. The world’s largest supercomputer is arguably SETI@home A $599 computer from Radio Shack is a very powerful computational engine. Currently runs on a half-million machines at any given time. With help from the SETI@home developers, LIGO scientists have created a distributed public all-sky pulsar search. 24-Feb-05 Venice Neutrino Telescope

Venice Neutrino Telescope Einstein@Home Versions are available for Windows, Mac, Linux. How does Einstein@home work? Downloads a 12 MB ‘snippet’ of data from Einstein@home servers Searches the sky in a narrow range of frequencies Uploads interesting candidates for further follow-up Screensaver shows where you are currently searching in the sky We invite all of you to join Einstein@Home and help us find gravitational waves. 24-Feb-05 Venice Neutrino Telescope

Einstein@Home Usage Test Version had about 7K Users 5x LIGO computing capacity OFFICIAL RELEASE on 20-Feb 24-Feb-05 Venice Neutrino Telescope

Venice Neutrino Telescope Einstein@Home Users I'm from Germany and was interested in the mysteries of the universe since I was a little boy. I read lots of magazines about astrophysics and astronomy. When I heard about the Einstein@Home project it was no question for me to participate. My job is to make original-sized design models of new Mercedes-Benz cars, especially the interieur. When I don't work I often play keyboards and percussions and sing some backing vocals in my cover-rock-band "Gilga-Mesh" 24-Feb-05 Venice Neutrino Telescope

Venice Neutrino Telescope Einstein@Home Users Hi, my name's John Slattery. I'm a 62 year old English teacher, originally from Boston, MA, currently living in Santa Fe, New Mexico where I'm tutoring, and teaching ESL. My hobbies: fitness, camping, hiking, reading, writing, surfing the Net I'm so very new at this; I'm not even sure what's going on. But it seemed, from the little I could understand, to be a worthwhile project. 24-Feb-05 Venice Neutrino Telescope

Venice Neutrino Telescope Einstein@Home Users 24-Feb-05 Venice Neutrino Telescope

LIGO Pulsar Search using personal computers Einstein@Home LIGO Pulsar Search using personal computers BRUCE ALLEN Project Leader Univ of Wisconsin Milwaukee LIGO, UWM, AEI, APS http://www.physics2005.org/events/einsteinathome/index.html http://einstein.phys.uwm.edu 24-Feb-05 Venice Neutrino Telescope