Many problems in astrophysics involve a tremendous scale separation. A particularly dramatic example is the case of supermassive black holes, whose impact is felt on all of these scales. I’ll show how recent multi-physics and multi-scale simulations have transformed our understanding of how such black holes could form, “where they come from,” and how they influence galaxies. With the novel ability to follow the radiation-magneto-thermo-chemistry from scales of megaparsecs down to horizon scales, we are now seeing that much of the “conventional wisdom” in the field needs to be revised. Simulations are predicting qualitatively new types of accretion disks which in turn completely change our intuition about how black hole seeds grow rapid, how quasars shine and behave in mergers, how stars form around black holes, and how their feedback couples to the interstellar medium. I’ll also briefly review some of our group’s recent work connecting these disparate scales in the context of star formation, dust, and cosmic rays, involving novel ideas about stellar pollution, the origins of magnetic fields, and how cosmic rays influence galaxies. 

Speaker: Phil Hopkins (California Institute of Technology)

The 2025 Fall Colloquium talks are held on Wednesdays at 3:00 PM. This colloquium is hosted by STScI and will be held as an in-person and virtual event.

You may join in person at STScI’s John N. Bahcall Auditorium or virtually on the STScI Research YouTube channel.

Please direct questions or comments to contact above. The 2025 Fall Colloquium Committee members are: Nimisha Kumari (STScI), Elena Manjavacas (STScI), Jack Neustadt (JHU), Kevin Schlaufman (JHU), Adam Smercina (STScI), Ethan Vishniac (JHU).