RASC Regular Meeting June 11, 2018, Winds of Change Around Black Holes

RASC Regular Meeting
TELUS World of Science – IMAX Theatre
FREE and open to the public.

6:00 PM Astro Art Show & Sale

6:30 PM Special Showing of IMAX film: In Saturn’s Rings narrated by LeVar Burton (film will start at 6:45pm)

7:30 PM Guest Speaker

Gregory Sivakoff
Winds of Change Around Black Holes

Illustration of an X-ray Binary
Image Credit: NASA/Swift/A. Simonnet, Sonoma State University

Accretion disks, where matter with angular momentum spirals down through a disk, occur around objects ranging from the youngest stars to supermassive black holes. But not all of this material reaches the center of the disk. Instead some material is accelerated away from the disk. These outflows can be ejected in a narrow opening angle (what astronomers call “jets”) or can be relatively unfocused (what astronomers call “winds”).  While we do not know the precise processes that accelerate and collimate winds and jets, magnetic fields almost certainly play a key role. My team and I study black hole X-ray binaries, stellar-mass black holes accreting from a nearby star. We combine observations across the electromagnetic spectrum to learn about the physics of accretion and jets. In this talk, I will discuss how we have revealed two new windows onto the physics of inflows and outflows in X-ray binaries: fast variability measured across the electromagnetic spectrum (which provides the potential to accurately identify the accretion physics that launch relativistic jets) and the modelling of changes in the X-ray brightness of black hole X-ray binaries (which implies that strong winds from the accretion disk are universal). With the advent of new and upcoming facilities, we have a huge potential to take advantage of these winds of change in the next decade.

Gregory Sivakoff

Gregory Sivakoff was awarded a BSc/BA from Brandeis University (Waltham, MA) in 2000 in Physics and Mathematics. Under a Fulbright Scholarship to the UK, Gregory then earned a MSc in Radio Astronomy from the University of Manchester. He returned to the US to study Astronomy, garnering a MSc in 2003 and a PhD in 2006, both studying the X-ray emission from early-type galaxies under Professor Craig Sarazin. Dr. Sivakoff then spent 2 years as a Postdoctoral Researcher at the Ohio State University and a 2.5 years as a Research Associate at the University of Virginia. In April 2011, Professor Sivakoff began an Assistant Professorship at the University of Alberta. Since 2017, Professor Sivakoff has been an Associate Professor there. Professor Sivakoff’s main research interests are in multiwavelength observational studies of compact stellar objects (black holes, neutron stars, and white dwarfs).

This year Professor Sivakoff has been awarded two honours: He is the 2018 Science Fellow awarded by Telus World of Science for his work in science communication, as well as the recipient of the University of Alberta’s 2018 Faculty of Science Research Award.