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According to Cold Dark Matter (CDM) cosmology, structure in the Universe grows from the “bottom up”, with small galaxies merging to form larger ones. Evidence of such mergers can be seen in faint streams and filaments visible around the Milky Way Galaxy and the nearby M31 galaxy.
But the CDM model predicts that we should see more of this structure than is currently observed. However, images obtained using even the largest, most advanced telescopes today contain scattered light that may be hiding this faint structure.
Dragonfly is designed to reveal the faint structure by greatly reducing scattered light and internal reflections within its optics. It achieves this using commercially available Canon 400mm lenses with unprecedented nano-fabricated coatings with sub-wavelength structure on optical glasses.
Also, Dragonfly images a galaxy through multiple lenses simultaneously—akin to a dragonfly’s compound eye—enabling further removal of unwanted light. The result is an image in which extremely faint galaxy structure is visible.
The array began imaging targets in 2013 from its home at the New Mexico Skies hosting facility. Images have shown Dragonfly is at least ten times more efficient than its nearest rival and will be able to detect faint structures predicted by current merger models.
The original co-principal-investigators for Dragonfly are U of T’s Prof. Roberto Abraham and Yale University’s Prof. Pieter van Dokkum, and they have recently been joined by Harvard’s Charlie Conroy as the third co-principal-investigator. At the U of T, the Dragonfly team also includes graduate students Jielai Zhang and Deborah Lokhorst.
Funding for Dragonfly was provided by Abraham’s NSERC Discovery Grant, with initial funds provided by the Dunlap Institute and Yale University, and NSERC equipment grants awarded in 2014 and 2016.
The Growth of Dragonfly:
CBC Radio Quirks & Quarks: A Strange New Kind of Galaxy Has No Dark Matter, And We Don’t Know Why
Washington Post: A new class of galaxy has been discovered, one made almost entirely of dark matter
CNN.com: “Dark Twin” of the Milky Way Galaxy discovered
Forbes.com: Newly Discovered Galaxy is Almost Entirely Made of Dark Matter
FOX News: Found: Dragonfly 44: a Strange Galaxy Made Mostly of Dark Matter
WIRED: Meet Dragonfly 44, the galaxy made of 99.9% dark matter
Nautil.us: How to Discover a Galaxy with a Telephoto Lens, Nautilus, 28 Jan 2016
Recent Dragonfly papers:
The Dragonfly Nearby Galaxies Survey
Spectroscopic Confirmation of the Existence of Large, Diffuse Galaxies in the Coma Cluster
Forty-seven Milky Way-sized, Extremely Diffuse Galaxies in the Coma Cluster
Ultra Low Surface Brightness Imaging with the Dragonfly Telephoto Array