Department of Physics, Engineering Physics & Astronomy

Queen's University
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Department of Physics, Engineering Physics & Astronomy
Department of Physics, Engineering Physics & Astronomy

Panchromatic Surveys of Resolved Stellar Populations

Jason Kalirai

Wednesday, February 1, 2012
11:30 AM @ Stirling 201


Nearby resolved stellar populations such as Galactic star clusters anchor our understanding of the Universe. Clusters are ideal testbeds to advance our knowledge of stellar evolution and structure, and provide a calibration of astrophysical relations that aim to interpret light across the Universe. Yet, over the past century of work, most of this effort has focused on visible light investigations given the lack of a high-resolution, sensitive, and wide-field infrared facility. This talk will highlight the first results from a new HST imaging survey of the best studied globular star cluster in the sky, 47 Tuc. The survey strategy uses 121 orbits with the Wide Field Channel (WFC) of the Advanced Camera for Surveys (ACS) and both the UVIS and IR channels of the newly installed Wide Field Camera 3 (WFC3) instrument. The full analysis of the data set reveals unprecedented panchromatic color-magnitude diagrams exhibiting complete stellar sequences that extend from the hydrogen burning limit, up to the brightest giants, and down to the coolest remnants in the cluster. These observations enable a new level of calibration for fundamental astrophysical relations.