Black hole ringdown and quasinormal modes

          @misc{ scivideos_PIRSA:16060014,
            doi = {10.48660/16060014},
            url = {https://pirsa.org/16060014},
            author = {Zimmerman, Aaron},
            keywords = {Cosmology},
            language = {en},
            title = {Black hole ringdown and quasinormal modes},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2016},
            month = {jun},
            note = {PIRSA:16060014 see, \url{https://scivideos.org/index.php/pirsa/16060014}}
          }
          

Abstract

The first detection of gravitational waves came with an unexpected windfall: a clear signal from the merger of two black holes into a final, spinning black hole. General Relativity predicts that following merger, the final black hole relaxes by emitting radiation in a characteristic spectrum of decaying modes. I will discuss these ``quasinormal modes'' and what can be learned from them, as well as the black hole ringdown observed in GW150914. I will also explore the exotic side of ringdown, including the modes of nearly extremal black holes, and a tool for understanding the ringdown of black holes which differ from the standard Kerr solution.