Abstract:

On 14 September 2015, the Advanced LIGO observatories observed a transient gravitational wave signal. Analysis of the results shows that the simplest interpretation of the signal is the merger event of two black holes of 36 and 29 solar masses at a distance of 1.3 billion lightyears. A new black hole of 62 solar masses was formed and 3 Solar masses of pure energy were radiated away in gravitational waves within 0.2 seconds. The observation marks several remarkable discoveries at once: the first direct detection of gravitational waves, the first direct evidence for the existence of massive black holes and the first observation of a binary black hole merger. In this seminar, I will give an overview of the detection and analysis of this historic event, in particular, discussing what astrophysical information was extracted from the signal and what tests of strong-field gravity were made possible. The observation has opened up a new era in strong-field gravity physics and astronomy, and I will discuss the main challenges and scientific breakthroughs that can be expected in the coming years.