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Photo credit: NASA/CXC/SAO

Einstein@home: how to find gravity waves with your home PC Michael Landry LIGO Hanford Observatory California Institute of Technology Say Hello to Einstein@home LHO June 8, 2005. Photo credit: NASA/CXC/SAO. Detecting a signal. Greg has talked about sources Now let’s talk about detection

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Photo credit: NASA/CXC/SAO

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  1. Einstein@home: how to find gravity waves with your home PCMichael LandryLIGO Hanford ObservatoryCalifornia Institute of TechnologySay Hello to Einstein@homeLHO June 8, 2005 Photo credit: NASA/CXC/SAO

  2. Detecting a signal • Greg has talked about sources • Now let’s talk about detection • If our detector was not moving with respect to a star, gravity waves would sound like a single tone • Gravity waves from dense spinning stars are Doppler shifted by the motions of the Earth relative to the star (FM) • Gravity waves are also amplitude modulated because interferometer sensitivity varies with direction (AM) Waves get Doppler shifted from relative motion

  3. Simulation:Gravitational Waves Seen & Heard Power vs frequency Play Me Power vs sky position (AM & FM modulation greatly exaggerated)

  4. Detecting a signal • Steps in detection: • Guess at what the signal might look like • Compare your guess to your data from your interferometer • This is called matched filtering • If you don’t find a signal, keeping guessing and comparing

  5. : Data from detector

  6. : Data from detector : “Guess” at signal

  7. : Data from detector

  8. : Data from detector : “Guess” at signal

  9. : Data from detector : “Guess” at signal

  10. : Data from detector : “Guess” at signal

  11. : Data from detector : “Guess” at signal

  12. : Data from detector : “Guess” at signal Match!!

  13. Why distributed computing? • e.g. searching 1 year of data, you have 3 billion frequencies in a 1000Hz band • For each frequency we need to search 100 million million independent sky positions • pulsars spin down, so you have to consider approximately one billion times more “guesses” at the signal • Number of templates for each frequency: ~100,000,000,000,000,000,000,000 • Clearly we rapidly become limited in the analysis we can do by the speed of our computer! Einstein@home!!! a.k.a. Distributed computing

  14. Einstein@home • Installation • Screensaver • Web pages • Getting help APS webpage http://www.physics2005.org/events/einsteinathome/index.html Einstein@home webpage http://einstein.phys.uwm.edu/

  15. Summary • Run Einstein@home on your home PC! Tell your friends! Tell your enemies! You may be the first person in history to detect gravity waves on your computer! • You should have received a pamphlet with instructions on how to load the screen saver • Included with the pamphlet is a survey; please fill this out and drop it in the box on the way out the door. Take a cookie for your trouble • Need help? landry_m@ligo-wa.caltech.edu • After the talks: I’ll demonstrate the installation if anyone is interested

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