College of Science

Seminar: Hassen Yesuf [UC Santa Cruz]

When a monster black hole is fed, will all hell break loose in a galaxy?

Feb 13, 2018 11:00 AM to Feb 13, 2018 12:00 PM at Building 8, Room 241

The quest for evidence of feedback from supermassive active black holes. 

Modeling galaxy formation and evolution in a cosmological context is one of the greatest challenges in astrophysics today. Large galaxy surveys in recent decades, however, have provided us with a wealth of information on millions of galaxies, and thus we now have a general outline of how galaxies form and evolve. Our current understanding of the formation of massive galaxies evokes regulation of star formation by supermassive black holes, weighing at least tens of millions times the mass of the sun. These monsters get fed by gas infall during titanic collisions between galaxies, and belch enormous energy that may destroy cold gas which otherwise fuels future star formation and black hole growth. I will present an overview of my past research on active black holes in galaxies. In particular, I will show evidence that 1) active black holes are common in galaxies that are ceasing to form stars rapidly after burst of recent star formation 2) they destroy cold gas in these post-starburst galaxies 3) they drive super galactic winds 4) they reside more commonly in galaxies with strong central concentration of stars. I will also briefly present my future research to do detailed study of galactic winds, structure, and star formation histories of simulated and observed galaxies using Bayesian statistics and machine learning methods.

Centaurus A Above: Image of the nearby galaxy Centaurus A shows spectacular gas outflows (shown in purple) driven by its active supermassive black hole at the center. In the optical band, the dust shrouded galaxy looks like the inset image on bottom right (Credit : Chandra Observatory).


10:50 am Refreshments

11:00 am Seminar

Building 8, Room 241