Virtual Lectures
The Department of Astronomy is pleased to introduce a new Virtual Lectures series. This series of four online events, distributed over two years, showcases the world-class science being undertaken by faculty, scientists and students in the Department. It is free and open to everyone, and is pitched at a level accessible to non-scientists. Each event is composed of a pair of 30-minute lectures, followed by question-and-answer sessions. For those unable to participate in a live event, a recording together with a brief synopsis will be posted below after completion of the event.
The Invisible Universe
Have you ever wondered what it would be like to have X-ray vision, or to see using ultrasound? What might our world look like to you? Over the past century, astronomers have developed these and other powers to make the invisible visible.
In this first event, which took place December 3rd 2020, Professor Eric Wilcots (Dean of the College of Letters & Science) introduces the Department of Astronomy and the Virtual Lectures series. The two inaugural lectures then follow: Professor Sebastian Heinz describes how X-ray echoes allow him to to map out the distribution of dust from nova outbursts, and Professor Rich Townsend explains how he leverages waves and oscillations to peer beneath the opaque surfaces of stars.
The recording of the event can be viewed here.
For further reading about X-ray echoes, see the first article (X-ray Dust Tomography: the New Frontier in Galactic Exploration) in this issue of the newsletter for the Chandra X-ray Observatory. If you're feeling brave, the following scientific papers may be of interest:
- The X-Ray Variable Sky as Seen by MAXI: The Future of Dust-echo Tomography with Bright Galactic X-Ray Bursts; L. Corrales, B. Mills, S. Heinz, & G. Williger 2019; The Astrophysical Journal, 874, 155.
- A Joint Chandra and Swift View of the 2015 X-ray Dust-scattering Echo of V404 Cygni; S. Heinz, L. Corrales, R. Smith, W. N. Brandt, P. G. Jonker, R. M. Plotkin, & J. Neilsen 2016, The Astrophysical Journal, 825, 15.
- Lord of the Rings: A Kinematic Distance to Circinus X-1 from a Giant X-Ray Light Echo; S. Heinz, M. Burton, C. Braiding, W. N. Brandt, P. G. Jonker, P. Sell, R. P. Fender, M. A. Nowak, & N. S. Schulz 2015; The Astrophysical Journal, 806, 265.
For further reading about stellar seismology, the first few sections of this review article by Gerald Handler provide a solid introduction to the topic (later sections become progressively more mathematical, however). The user and reference guides for the GYRE asteroseismology software can be viewed online here, and the technical aspects of the software are desribed in these scientific papers:
- Angular momentum transport by heat-driven g-modes in slowly pulsating B stars; R. H. D. Townsend, J. Goldstein, & E. G. Zweibel 2018; Monthly Notices of the Royal Astronomical Society, 475, 879
- GYRE: an open-source stellar oscillation code based on a new Magnus Multiple Shooting scheme; R. H. D. Townsend & S. A. Teitler 2013; Monthly Notices of the Royal Astronomical Society, 435, 3406.
- The Contour Method: a New Approach to Finding Modes of Nonadiabatic Stellar Pulsations; J. Goldstein & R. H. D. Townsend 2020; The Astrophysical Journal, 899, 116