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<TITLE>Helen Sawyer Hogg Free Public Lecture - May 25 in Hamilton, ON</TITLE>
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<P><FONT SIZE=2><A HREF="http://www.physics.mcmaster.ca/casca2015/?page_id=2">http://www.physics.mcmaster.ca/casca2015/?page_id=2</A><BR>
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The Helen Sawyer Hogg Public Lecture is sponsored jointly by the Canadian Astronomical Society/Socit Canadienne d’Astronomie and the RASC. It is so named in recognition of the lifelong contributions of Helen Sawyer Hogg towards increasing public awareness and appreciation of the Universe around us.<BR>
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In odd-numbered years, the lecture is hosted by CASCA, this year at their annual assembly in Hamilton. The presenter this year happens to be the RASC Toronto Centre’s honorary president, Dr. Roberto Abraham. The title is ‘First Results from Dragonfly’.<BR>
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"In this talk I will describe some early results from the Toronto/Yale Dragonfly Telephoto Array, a robotic imaging system optimized for testing some of the most fundamental predictions of galaxy formation models. Dragonfly is composed of multiple commercial 400mm f/2. telephoto lenses which utilize novel nanostructure-based optical coatings that minimize scattered light and ghosting. Dragonfly is optimized to explore the night sky in a totally different way than the Hubble or Gemini or Keck telescopes.<BR>
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Dragonfly has low resolution and a small aperture, but its focal ratio is very ‘fast’ and it is designed to have exquisite control over systematics. In its chosen niche no other telescope on the planet (or in space) can touch Dragonfly, which is capable of directly imaging large low surface brightness structures (such as galactic stellar haloes and faint dwarf galaxies) about 10x fainter than is possible with conventional telescopes. In this talk I’ll show some early results, mainly focusing on the properties of ultra-faint stellar haloes. I’ll also report the discovery of gigantic stellar disks underlying nearby galaxies, and will describe the discovery of a new class of ghostlike galaxies that are as big as the Milky Way but have about 1/1000th of its mass." </FONT></P>
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