Chandra's Impact on Astrophysics and Active Galaxy Research*

NASA's Chandra X-ray Observatory was launched on 23 July 1999 by the Space
Shuttle Columbia. Now celebrating its 20th year of operations, Chandra
continues to be an indispensable tool for expanding the frontiers of knowledge
throughout astrophysics. Chandra's unique, sub-arcsecond, spatial resolution
and high precision spectroscopy have led to major advances in our understanding
of celestial sources from exo-planetary atmospheres to clusters of galaxies,
cosmology to the merging neutron stars found via gravitational waves.
I will provide a review of Chandra and its broad scientific impact (>7300
science papers to date), before concentrating on Chandra's impact on our
knowledge and understanding of active galaxies, and the super-massive black holes located in
their cores.