Chandra Explores Sagittarius A*'s Event Horizon Dynamics: X-ray and Multi-wavelength Variability

The last century has seen exciting tests of general relativity and the LIGO-Virgo observatories have now definitively discovered black holes. And yet we are only beginning to approach the event horizon with electromagnetic observations. Sagittarius A* is one of the closest supermassive black holes targeted by the Chandra X-ray Observatory, as well as VLT's GRAVITY instrument, the Event Horizon Telescope, and many more. It thus offers an exciting opportunity for coordinated, multi-wavelength campaigns, which are poised to identify the origin of observed X-ray and IR variability, connect it to horizon-scale structure in the submm, and distinguish between competing models: hot spots, inflow/outflow, reconnection regions, shocks, or even magnetosphere gaps. I will review recent highlights from Chandra and multi-wavelength observations of Sgr A* and prospects for future discovery.