Both stellar mass and supermassive black holes can vary in brightness extremely rapidly, changing by orders of magnitude within hours. This variability gives us a powerful tool to understand the accretion disks around black holes, and the relativistic winds that they can launch. Because the X-ray spectra are made up of multiple complex variable components, the observed variability can be strongly energy dependent. By calculating the variance of X-ray lightcurves as a function of energy, we can build a variance spectrum. These spectra have been used to qualitatively study black hole variability for many years, but are rarely used quantitatively. I will present recent results from an ongoing research program to model variance spectra of compact objects, including a new method for detecting ultra-fast outflows, implications for accretion disk physics and new constraints on AGN feedback.

Zoom recording:  https://uky.zoom.us/rec/share/z8MTXvJhSmbuS3lYhUsiczW67IPyTDUGMYHrCWXbESp8kCbnmy53RMeJyPfQ66oL.H0J1IJ9f7C5H-iS2

“Some Intersections of Art and Science”

 Prof. Frank Wilczek, Massachusetts Institute of Technology.

 Public lecture: Thursday, April 28, 7:30 pm, Memorial Hall 

Abstract: There are profound reasons, rooted in the nature of human cognition and perception, why art and science have a lot to offer one another.   I will display some important historical examples of their synergy, and point out some emerging opportunities.  Several striking images are an integral part of the presentation. 

Frank Wilczek is an American theoretical physicist, mathematician, and Nobel laureate.  He is the Herman Feshbach Professor of Physics at Massachusetts Institute of Technology. Along with David Gross and H. David Politzer, Wilczek was awarded the Nobel Prize in Physics (2004) for the discovery of asymptotic freedom in the theory of strong interaction.

Wilczek's lecture is free and open to the general public.   A book signing will follow. 

This event is supported by the Departments of Physics and Astronomy, Mathematics, Statistics, Chemistry, the College of Engineering, the College of Arts and Sciences, the Graduate School, and the Vice President for Research.  The organizers thank the  Dr. J. C. Eaves Undergraduate Excellence Fund in Mathematics and  Milton Huffaker for their generous support.