Jielai Zhang (University of Toronto)

Jielai Zhang colloquium: Exploring the low surface brightness Universe with the Dragonfly Telephoto Array

Abstract

The low surface brightness Universe is largely unexplored. The
limiting factors for low surface brightness observations are not photon
statistics or image resolution, instead they are systematic factors such as a
telescope’s internal reflections, sky subtraction, flat fielding and the
wide-angle point-spread-function. The Dragonfly Telephoto Array addresses
these factors by a combination of hardware and software. The telescope
consists of 48 commercial Canon telephoto lenses, and is able to see low
surface brightness structures about 10 times fainter than previously possible
with its 2.4 x 3.2 degree wide field of view. I will describe the technology
behind Dragonfly, and how I and my team have used it to discover enormous
stellar disks, properties of interstellar dust and ultra-diffuse-galaxies.