1. Heikenwaelder Hugo, heikenwaelder.at [CC BY-SA 2.5]
Astro-Particle Physics 12
Gravitational waves
Heikenwaelder Hugo, heikenwaelder.at [CC BY-SA 2.5]
Manfred Jeitler
WS 2018/19

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

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
PSR B (also known as PSR J and PSR ) is a pulsar in a binary star system, in orbit with another neutron star around a common center of mass. In 1974 it was discovered by Russell Alan Hulse and Joseph Hooton Taylor, Jr., of Princeton University, a discovery for which they were awarded the 1993 Nobel Prize in Physics. It is also called the Hulse-Taylor binary pulsar after its discoverers.
pulse period is 59 milliseconds
orbit period is 7.75 hours

6. Michelson interferometer

7. LIGO (Laser Interferometer Gravitational Wave Observatory, USA)
measurement of gravitational waves
The gravitational interaction is so weak that the “graviton” which is supposed to mediate it has not been found yet. It is hoped to find gravitons and gravitational waves arriving from outer space (for instance from supernova explosions). The expected effects are very small and demand very accurate detectors and an extremely good compensation of interfering environmental effects.
LIGO (Laser Interferometer Gravitational Wave Observatory, USA)

10. GW170817

11. localization of source

13. present and future gravitational-wave observatories

14. 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.