Wednesday, May 17, 2017
4:00 pm
Cahill, Hameetman Auditorium – Cahill Center for Astronomy and Astrophysics

Astronomy Colloquium

Exploring the low surface brightness sky with the Dragonfly Telephoto Array
Pieter van Dokkum, Yale

The talk will describe 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 unexpected result so far is the discovery of a population of Milky Way-sized, very low surface brightness galaxies in rich clusters. Follow-up HST imaging and extremely deep Keck spectroscopy of two of these "Ultra Diffuse Galaxies" show that they are massive and dark matter dominated, and have large numbers of globular clusters.

Contact Althea E. Keith aek@astro.caltech.edu at 626-395-4973
Add this event to my calendar