Revealing the Origin and Cosmic Evolution of Supermassive Black Holes
  The next generation of electromagnetic and gravitational wave observatories
will open unprecedented windows to the birth of the first supermassive black
holes. This has the potential to reveal their origin and growth in the first
billion years, as well as the signatures of their formation history in the
local Universe. With this in mind, we outline three key focus areas which will
shape research in the next decade and beyond: (1) What were the "seeds" of the
first quasars; how did some reach a billion solar masses before z$\sim7$? (2)
How does black hole growth change over cosmic time, and how did the early
growth of black holes shape their host galaxies? What can we learn from
intermediate mass black holes (IMBHs) and dwarf galaxies today? (3) Can we
unravel the physics of black hole accretion, understanding both inflows and
outflows (jets and winds) in the context of the theory of general relativity?
Is it valid to use these insights to scale between stellar and supermassive
BHs, i.e., is black hole accretion really scale invariant? In the following, we
identify opportunities for the Canadian astronomical community to play a
leading role in addressing these issues, in particular by leveraging our strong
involvement in the Event Horizon Telescope, the {\it James Webb Space
Telescope} (JWST), Euclid, the Maunakea Spectroscopic Explorer (MSE), the
Thirty Meter Telescope (TMT), the Square Kilometer Array (SKA), the
Cosmological Advanced Survey Telescope for Optical and ultraviolet Research
(CASTOR), and more. We also discuss synergies with future space-based
gravitational wave (LISA) and X-ray (e.g., Athena, Lynx) observatories, as well
as the necessity for collaboration with the stellar and galactic evolution
communities to build a complete picture of the birth of supermassive black
holes, and their growth and their influence over the history of the Universe.
