The universe through the window of gravitational-waves and binary black holes
Abstract: Since the first detection of gravitational-waves, we have observed about 100 mergers of binary systems of black holes and neutrons stars. These events that we had not witnessed before posed new questions individually and collectively. Black holes that should not have come from stellar evolution were observed and extra features in their mass distribution were found. I will first talk on the necessary techniques for detecting the gravitational-wave events and for making astrophysical inferences; and the new advances including the first gravitational-wave detection with a quantum computer. Then I will discuss what we have learned from the binary black hole mergers so far astrophysically and a possible formation scenario of them where an initially bound three black hole system gives two consecutive mergers.