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

- 24-Feb-05Venice Neutrino Telescope2 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-05Venice Neutrino Telescope3 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, h mn. 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 h mn 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 45 0 instead of 90 0 from each other.

- 24-Feb-05Venice Neutrino Telescope4 Detection of Gravitational Waves Detectors in space LISA Gravitational Wave Astrophysical Source Terrestrial detectors Virgo, LIGO, TAMA, GEO AIGO

- 24-Feb-05Venice Neutrino Telescope5 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-05Venice Neutrino Telescope6 LISA The diagram shows the sensitivity bands for LISA and LIGO

- 24-Feb-05Venice Neutrino Telescope7 Detecting a passing wave …. Free masses

- 24-Feb-05Venice Neutrino Telescope8 Detecting a passing wave …. Interferometer

- 24-Feb-05Venice Neutrino Telescope9 Interferometer Concept l Laser used to measure relative lengths of two orthogonal arms As a wave passes, the arm lengths change in different ways…. …causing the interference pattern to change at the photodiode  Arms in LIGO are 4km  Measure difference in length to one part in or meters Suspended Masses

- 24-Feb-05Venice Neutrino Telescope10 Simultaneous Detection 3002 km (L/c = 10 ms) Hanford Observatory Caltech Livingston Observatory MIT

- 24-Feb-05Venice Neutrino Telescope11 LIGO Livingston Observatory

- 24-Feb-05Venice Neutrino Telescope12 LIGO Hanford Observatory

- 24-Feb-05Venice Neutrino Telescope13 LIGO Goals and Priorities l Interferometer performance »Integrate commissioning and data taking »Obtain one year of integrated data at h = by 2008 l Physics results from LIGO I »Initial upper limit results by early 2003 »First search to begin in 2005 »Reach LIGO I goals by 2008 l 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-05Venice Neutrino Telescope14 Lock Acquisition

- 24-Feb-05Venice Neutrino Telescope15 What Limits LIGO Sensitivity? lSeismic noise limits low frequencies lThermal Noise limits middle frequencies lQuantum nature of light (Shot Noise) limits high frequencies lTechnical issues - alignment, electronics, acoustics, etc limit us before we reach these design goals

- 24-Feb-05Venice Neutrino Telescope16 Evolution of LIGO Sensitivity

- 24-Feb-05Venice Neutrino Telescope17 An earthquake occurred, starting at UTC 17:38. From electronic logbook 2-Jan-02 Detecting Earthquakes

- 24-Feb-05Venice Neutrino Telescope18 Detect the Earth Tide from the Sun and Moon

- 24-Feb-05Venice Neutrino Telescope19 Science Runs S2 ~ 0.9Mpc S1 ~ 100 kpc E8 ~ 5 kpc NN Binary Inspiral Range S3 ~ 3 Mpc Design ~ 14 Mpc A Measure of Progress Milky Way AndromedaVirgo Cluster

- 24-Feb-05Venice Neutrino Telescope20 Astrophysical Sources l Compact binary inspiral: “chirps” »NS-NS waveforms are well described »BH-BH need better waveforms »search technique: matched templates l Supernovae / GRBs: “bursts” »burst signals in coincidence with signals in electromagnetic radiation »prompt alarm (~ one hour) with neutrino detectors l Pulsars in our galaxy: “periodic” »search for observed neutron stars (frequency, doppler shift) »all sky search (computing challenge) »r-modes l Cosmological Signals “stochastic background”

- 24-Feb-05Venice Neutrino Telescope21 Detection of Periodic Sources l 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-05Venice Neutrino Telescope22 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-05Venice Neutrino Telescope23 Directed Pulsar Limits on Strain S1 J S2 J1910 – 5959D: h 0 = 1.7 x Crab pulsar Red dots: pulsars are in globular clusters - cluster dynamics hide intrinsic spin- down properties Blue dots: field pulsars for which spin-downs are known h 95 1 PDF 0 strain Marginalized Bayesian PDF for h

- 24-Feb-05Venice Neutrino Telescope24 Directed Pulsar Search 28 Radio Sources

- 24-Feb-05Venice Neutrino Telescope25 R moment of inertia tensor gravitational ellipticity of pulsar Upper limit on pulsar ellipticity.. NEW RESULT 28 known pulsars NO gravitational waves e < – (no mountains > 10 cm

- 24-Feb-05Venice Neutrino Telescope26 EM spin-down upper-limits LIGO upper-limits from h max J S1 S2 Ellipticity Limits Red dots: pulsars are in globular clusters - cluster dynamics hide intrinsic spin-down properties Blue dots: field pulsars for which spin-downs are known Best upper-limits: J1910 – 5959D: h 0 < 1.7 x J2124 – 3358:  < 4.5 x How far are S2 results from spin-down limit? Crab: ~ 30X

- 24-Feb-05Venice Neutrino Telescope27 Detection of Periodic Sources l 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-05Venice Neutrino Telescope28 l A maximum-sensitivity all-sky search for pulsars in LIGO data requires more computer resources than exist on the planet. l The world’s largest supercomputer is arguably »A $599 computer from Radio Shack is a very powerful computational engine. »Currently runs on a half-million machines at any given time. l With help from the developers, LIGO scientists have created a distributed public all- sky pulsar search.

- 24-Feb-05Venice Neutrino Telescope29 l Versions are available for Windows, Mac, Linux. l How does work? »Downloads a 12 MB ‘snippet’ of data from 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 l We invite all of you to join and help us find gravitational waves.

- 24-Feb-05Venice Neutrino Telescope30 Usage Test Version had about 7K Users 5x LIGO computing capacity OFFICIAL RELEASE on 20-Feb

- 24-Feb-05Venice Neutrino Telescope31 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 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-05Venice Neutrino Telescope32 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-05Venice Neutrino Telescope33 Users

- 24-Feb-05Venice Neutrino Telescope34 LIGO Pulsar Search using personal computers BRUCE ALLEN Project Leader Univ of Wisconsin Milwaukee LIGO, UWM, AEI, APS einsteinathome/index.html