Annual General Meeting, October 14th 2016
“Exploring the ghostly side of galaxies with Dragonfly” with Dr. Roberto Abraham, University of Toronto professor, Dept of Astronomy & Astrophysics
Bigger telescopes are usually better telescopes…. but not always. In this talk I will explore the ghostly world of large low surface brightness structures, such as galactic stellar halos, low-surface brightness dwarf galaxies, and other exotica such as supernova light echoes. These objects are nearly undetectable with conventional telescopes, but their properties may hold the key to understanding how galaxies assemble. I will describe why finding these objects is important, and why it is so devilishly difficult.
I will also describe a bizarre new telescope (the Toronto/Yale/Harvard Dragonfly Telephoto Array, a.k.a. Dragonfly) which is now being used to explore the low surface brightness universe and is testing some of the most fundamental predictions of galaxy formation models. Dragonfly is comprised of 48 commercial 400 mm f/2.8 telephoto lenses which utilize novel nanostructure-based optical coatings that minimize scattered light and ghosting. I’ll showcase some our early results, mainly focusing on the properties of ultra-faint stellar halos. I’ll also report the discovery of gigantic stellar disks underlying nearby galaxies, and will describe the discovery of a new class of ghostlike galaxies that are as big as the Milky Way but have about 1/1000 of its mass.