2014-06-27-Prof. Roberto Abraham

The Dragonfly Telephoto Array and the Low Surface Brightness Universe

Abstract:

I will describe the thinking behind, and some early results from, the Toronto/Yale/Harvard Dragonfly Telephoto Array (a.k.a. Dragonfly). Dragonfly is a robotic imaging system optimized for the detection of extended ultra low surface brightness structures in the nearby Universe.

Dragonfly is probably the craziest-looking telescope you will ever see. It is comprised of 48 commercial 400 mm f/2.8 telephoto lenses which have high-performance nanostructure optical coatings designed to minimize scattered light and ghosting. The array functions as the equivalent of a 1m diameter refractor with a focal ratio of f/0.4, the largest and most sensitive all-lens telescope in existence. I will describe the operating principles behind the instrument, highlighting the strengths and weaknesses of the overall concept.

Dragonfly is more like a physics experiment than it is like a conventional telescope, and our team is using the instrument to undertake a range of experiments with the goal of better understanding the nature and distribution of dark matter. I’ll describe some early results on ultra-diffuse galaxies and galactic halos, and then describe how we are upgrading the array in order to enable the direct imaging of the circumgalactic medium, the (very poorly understood) repository of most of the baryons in the Universe. Our stretch goal is to directly image the Cosmic Web, a large-scale network of dark matter filaments that connects galaxies to each other, and which is thought to be the largest coherent structure in the Universe.

Host: Paul Schechter