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Gravitational waves astronomy for the new millennium

Gravitational waves astronomy for the new millennium. Vitor Cardoso (CENTRA/IST & U. Mississippi) ‏. Collaborators: Berti, Bruegmann, Gonzalez, Pani, Pretorius, Sperhake, Will, Witek, etc. IBERICOS 2009, Madrid, 16 April. (Image: MPI for Gravitational Physics/W.Benger-Z). Plan.

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Gravitational waves astronomy for the new millennium

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  1. Gravitational wavesastronomy for the new millennium Vitor Cardoso (CENTRA/IST & U. Mississippi)‏ Collaborators: Berti, Bruegmann, Gonzalez, Pani, Pretorius, Sperhake, Will, Witek, etc IBERICOS 2009, Madrid, 16 April (Image: MPI for Gravitational Physics/W.Benger-Z)

  2. Plan GWs in GR Coalescence of black hole binaries in GR Other theories

  3. What are GWs? “+” polarization: “x” polarization: Wave equation: c! Observable: Gws are tidal forces!

  4. Do they exist? slow down of a binary pulsar

  5. Do they exist? slow down of a black hole in quasar OJ 287: strong-field tests Valtonen et al, Nature452, 851-853 (17 April 2008)

  6. Detection

  7. Typical signal for coalescing binaries LIGO-G080249-00-Z

  8. Typical stretch of data LIGO-G080249-00-Z

  9. Typical needle in a haystack problem LIGO-G080249-00-Z (but with a smaller needle)

  10. Typical needle in a haystack problem LIGO-G080249-00-Z

  11. Matched filtering LIGO-G080249-00-Z

  12. Matched filtering LIGO-G080249-00-Z

  13. Matched filtering LIGO-G080249-00-Z

  14. Matched filtering LIGO-G080249-00-Z

  15. Matched filtering LIGO-G080249-00-Z

  16. Matched filtering LIGO-G080249-00-Z

  17. LIGO-G080249-00-Z The merger problem: we need NR Lack of knowledge Wrong filter Mismatch Decreased SNR 3% Mismatch: 10% lost events!

  18. BH Binary Coalescence Rates for LISA (similar variations for LIGO)

  19. BH coalescence Courtesy Marcus Thierfelder and Bernd Bruegmann

  20. Typical signal for BH binaries InspiralMergerRingdown (Berti, VC, Sperhake, Gonzalez, Brugmann, Hannam & Husa,PRD76:064034,2007)‏

  21. Inspiral Luminosity distance Angular resolution (sterad)‏ reduced mass Chirp mass (Faye et al ’06, Kidder ‘08)

  22. Inspiral InspiralPN waveforms High-precision tests of GR • Mass, distance, angular location to fractions of a percent Luminosity distance Luminosity distance Angular resolution (sterad)‏ Angular resolution (sterad)‏ reduced mass reduced mass Chirp mass 2x106M (solid) and 2x107M (dashed)‏(Berti, Buonanno & Will, PRD71:084025,2005)‏

  23. Inspiral InspiralPN waveforms High-precision tests of GR • Mass, distance, angular location to fractions of a percent • Propagation speed, Polarization states • Masslessness of graviton: speed depends on wavelength, therefore phasing changes during inspiral (Arun and Will, ‘09) • EOS for dark energy: identify host galaxy and measure redshift from EM. Distance and redshift gives EOS (Arun et al, ‘08) Luminosity distance Angular resolution (sterad)‏ reduced mass

  24. LIGO-G080249-00-Z BH ringdown: characteristic modes (Leaver ’85; Berti, VC & Starinets, ‘09) f= 12 Msun/M kHz = 0.012 (106Msun)/M Hz t =55x10-6M/Msun s= 55 M/(106Msun) s

  25. LIGO-G080249-00-Z “No-hair” tests • One mode detection: • Suppose we know which mode we are detecting (eg. l=m=2); then • Measure of black hole’s mass and angular momentum (Echeverria ’89, Finn ’92) f(M,j),t(M,j) M(f,t), j(f,t) • Multi-mode detection: • First mode yields (M,j) • In GR, Kerr modes depend onlyon M and j: second mode yields test that we are observing a Kerr black hole, if we can resolve the modes: (Dreyer et al. ’05; Berti, VC & Will ’06)

  26. Ringdown: LISA j=0,0.8,0.98 Berti, VC & Will, PRD71:084025,2005)‏

  27. On-going: Credible consistent theories of gravity • Chern-Simons (Sopuerta & Yunes ‘09, Alexander & Yunes ‘08), Dilaton-Gauss-Bonnet (VC & Pani, ‘09), etc. Maybe a general framework?(Pretorius & Yunes, ‘09) • Numerical Relativity in different theories (see Helvi’s talk) Work in progress • Good news for gravitational-wave detection • Bad news for quest for “corrected” theory of gravity

  28. Conclusions Exciting times for gravitational wave astronomy: • Advances in theory and numerical relativity • Earth-based detectors have reached design sensitivity • Probe central engine for GRBs • Demographics of very compact objects (mass & spin to better than 1%!)‏ • Does GR describe strong field regime? • ?

  29. Thank you

  30. Typical BH binary

  31. Order of magnitude estimate For a coalescing compact object into a black hole: Distance Earth-Sun (1.5 x 107 km)…. …stretches by a fraction of an atom!

  32. BH coalescence

  33. LIGO-G080249-00-Z The merger problem

  34. Interferometry Hanford, WA Livingston, LA

  35. LIGO-G080249-00-Z BH ringdown: combing 3 hairs

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