1 Astro-Particle Physics 9 Gravitational waves Manfred Jeitler

2 Mass is always positive Differently from electric charge, magnetic fields and color charge, there is no “negative” mass Even antimatter has “positive” mass Therefore there cannot be gravitational monopole or dipole fields Have to look for quadrupole fields

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5 Hulse-Taylor binary indirect demonstration of gravitational waves Orbital decay of PSR B The data points indicate the observed change in the epoch of periastron with date while the parabola illustrates the theoretically expected change in epoch according to general relativity. Nobel prize 1993 to Hulse and Taylor

6 Michelson interferometer

7 Northern leg (x- arm) of LIGO interferometer on Hanford Reservation

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9 Ground-based detectors like the Laser Interferometer Gravitational-Wave Observatory (LIGO) will view the high-frequency waves from transient phenomena, like supernovae and the final minutes of inspiraling neutron-star binaries. LISA will observe the lower frequency waves from quasi-periodic sources, like compact star binaries long before coalescence, and supermassive black-hole binaries in the final months of coalescence.