Clusters of galaxies are the most massive things in the Universe and the first places scientists found dark matter, the mysterious, unseen material that is the majority of matter in the Universe. About forty years ago, astronomers discovered that the clusters are very bright X-ray sources. Prof. Henry will explain how studying the X-rays made by these clusters has given scientists a few insights into dark matter. He will also tell some stories about his adventures and misadventures building and flying the instruments used to make these studies.
Pat Henry has been a professor at the University of Hawaii Institute for Astronomy since 1981. He received his PhD from the University of California, Berkeley in 1974. He then worked at Smithsonian Astrophysical Observatory, located at Harvard University. There he was the project scientist for one of the instruments on the first imaging X-ray astronomy observatory and for the integration of the observatory with its spacecraft. In 2004, he received the Humboldt Senior Research Prize from the Humboldt Foundation of Germany. This year, he was one of four scientists to receive the Rossi Prize from the High Energy Astrophysics Division of the American Astronomical Society for his studies of clusters of galaxies.