Colloq Abstract -vanDokkum
April 7
11am Mountain
Pieter van Dokkum (Yale)
Exploring the low surface brightness sky with the Dragonfly Telephoto Array
Abstract:
The talk will describe first results from a new telescope concept, optimized for low surface brightness imaging. The Dragonfly Telephoto Array consists of 48 high-end telephoto lenses, creating the equivalent of an f/0.4 refractor with a 1m aperture. Early results from Dragonfly include a measurement of the stellar halos around nearby spiral galaxies down to ~32 mag/arcsec^2 and the identification of new satellite galaxies. Perhaps the most spectacular result so far is the discovery of a population of Milky Way-sized, very low surface brightness galaxies in rich clusters. A follow-up study of one of these "Ultra Diffuse Galaxies" shows that it is massive and extremely dark matter dominated, with a dark matter fraction of 98% inside its effective radius.
