Infrared Diagnostics of Galaxy Formation and Evolution

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The nature of galaxy formation and evolution remains challenging to unravel due to the sheer diversity of galaxies in the Universe and the cosmic timescales over which they evolve. While broad trends have been discovered, detailed studies of large samples of galaxies are required to make strong inferences about formation histories and evolutionary processes. In recent times, significant progress has been made in the nearby universe through massive optical imaging spectroscopic surveys of thousands of galaxies. We are beginning to obtain sufficient statistics to quantify the aggregate properties for broad ranges of galaxy parameters. Despite this progress, our view of galaxies in the distant universe continues to be limited, which is essential to complete the evolutionary picture. I propose a highly coupled infrared (IR) instrumentation and scientific program that takes advantage of cutting-edge technologies such as adaptive optics (AO), integral field spectroscopy, and astrophotonics to tackle long standing questions in the field of galaxy formation and evolution: 1) What are the initial conditions from which stars form? 2) What role does environment play? 3) What internal feedback processes impact the growth of galaxies? Through the use of powerful new instruments such as the wide-field IR integral field spectrograph (WIFIS), and the upcoming Gemini IR multi-object spectrograph (GIRMOS), we will carry out detailed surveys of both nearby and distant galaxies that directly address these questions and provide legacy value to the international community. WIFIS offers the opportunity to study the rest-frame IR spectrum and constrain stellar initial mass function. Additionally, through a survey for the most ancient metal-poor stars in our Milky Way bulge, enabled by our AO developments, we will probe the nature of star formation during the early universe. This work will test long held assumptions about star formation and stellar evolution that are the foundational for understanding galaxies. GIRMOS will open a complementary window to the distant universe, allowing us to do galaxy surveys in a similar scale as what is being done locally. This will lead to breakthroughs in our understanding of the Universe, particularly how galaxies form and how our Milky Way developed over its lifetime. My proposal also includes a research program in instrumentation development within the domains of AO and photonics. This research has the potential for significant payoffs in the future for large and extremely large telescope instrumentation and commercial/defense applications. HQP will play leadership roles in all of the proposed projects. The program will train ~40 HQP. The proposed activities will provide a diverse set of skills thanks to the combination of scientific and instrumentation research that all HQP will participate in. This is a winning combination for HQP who intend to excel within academia or join the highly skilled industrial workforce.