M87* and Sgr A*
M87*
- Mass: ~6.5 billion solar masses
- Location: Center of galaxy M87
- Environment: Steady, bright jet
- Variability: Slow (weeks/months)
Sgr A*
- Mass: ~4 million solar masses
- Location: Center of Milky Way
- Environment: Fainter, variable accretion
- Variability: Fast (minutes/hours)