General Relativity: Relativistic Gravity

• Big Al
• Principle of Equivalence
  an especially nice animation of the rocket experiment
• gravitational redshift verified in the lab: Pound & Rebka (1960)
• The first evidence for light bending: 1919 eclipse, reported to the Royal Society and in the New York Times
• More recent evidence on galactic scales: rings, galaxy clusters here and here

Evidence for Black Holes

• X-ray binaries: Cygnus X-1
• Milky Way center:
  • Radio overview
  • The power of adaptive optics
  • Stellar orbits: Munich group, UCLA group
  • The 2020 Nobel Prize in Physics
  • possibly related: gamma-ray bubbles
  • coming soon(?): Event Horizon Telescope image of a black hole, perhaps like this
• other galaxies
  • active galaxies: M87; AGN gallery
  • gravitationally lensed quasar: the Einstein cross
  • quasar and host galaxies
  • supermassive black holes
  • black holes and galaxies somehow know about each other
  • important clues: a binary supermassive black hole pairs and even triples! optical detection by our own Prof. Xin Liu, X-ray

Imaging a Black Hole: M87^*

• Virgo cluster of galaxies
• M87 at center
• M87 jet: our closest AGN!
• Event Horizon Telescope: array
• expectations: black hole ray tracing, simulations
• EHT image of M87^*! paper: EHT Collaboration (2019)
• putting it all together