APPROACHING THE HORIZON FOR UNDERSTANDING BLACK HOLE ASTROPHYSICS

Sera Markoff –  Univ. Amsterdam

Black holes are crucial players in the universe, able to very efficiently convert energy from gravitationally captured matter into other forms. The most dramatic example of this phenomenon are the relativistic jets launched near the event horizon, that somehow manage to carry this converted energy out to scales millions to billions of times larger. This effect can suppress star formation and galaxy evolution on the largest scales, and along the way jets are also potentially accelerating the highest energy cosmic rays and neutrinos detected on earth. Deriving a complete theory for these big picture questions about black holes and their jets requires detailed information about processes occurring just outside the event horizon, a region we have only recently gained access to with the Event Horizon Telescope (EHT). After a broad review about our current basic understanding, I will present a few examples of what we are learning from our recent EHT observations of M87, Cen A, and as of this year, Sgr A*. In particular I will focus on the gains made by combining EHT with observations from other multi-wavelength facilities. I will also discuss the outlook for the coming decade of studies.