GeminiFocus April 2018 | Page 2

1 Director’s Message Laura Ferrarese 3 Classifying Ultra-faint Satellite Systems in the Milky Way’s Halo Blair Conn and Helmut Jerjen 8 Science Highlights John Blakeslee 13 On the Horizon Gemini staff contributions 17 News for Users Gemini staff contributions 21 Public Outreach Efforts Soar in Hawai‘i and Chile Janice Harvey and Manuel Paredes ON THE COVER: Composite image of the ultra-diffuse galaxy NGC1051-DF2 which was found to be devoid of dark matter. Also shown is a blow-up of one of the galaxy’s globular clusters and a spectrum of it from the W.M. Keck Observatory. The work, led by Pieter van Dokkum of Yale University, is featured in this issue’s Science Highlights starting on page 8. GeminiFocus April 2018 GeminiFocus is a quarterly publication of the Gemini Observatory 670 N. A‘ohoku Place, Hilo, Hawai‘i 96720, USA Phone: (808) 974-2500 / Fax: (808) 974-2589 Online viewing address: Managing Editor: Peter Michaud Associate Editor: Stephen James O’Meara Designer: Eve Furchgott/Blue Heron Multimedia Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation or the Gemini Partnership. ii GeminiFocus April 2018