Dr. Churchill co-heads the Quasar Absorption Line – Galaxy Evolution Group, a collaborative effort between NMSU, Swinburne University of Technology, and Penn State. This research group studies galaxy evolution from the perspective of gas flows through galaxies. We are examining the connections between the large extended halos around galaxies (known as the circumgalactice medium), which can be 10 times larger than the stellar disks, and the galaxies themselves. In particular, we are studying the circumgalactic medium in the context of the stellar feedback mechanisms driving outflows and the cosmic web structures of the intergalactic medium from which gas inflows. The collaboration recently published the MgII Absorber-Galaxy Catalog (MAGIICAT). The collaboration is also hard at work studying OIV absorption in the halos of galaxies as part of its Mutliphase Galaxy Halos Project. Dr. Churchill and his collaborators make extensive use of the Keck Observatory’s 10-meter telescopes, the Apache Point 3.5-meter telescope, and the Hubble Space Telescope.
Dr. Churchill specializes in observational spectroscopic techniques and analysis, including long slit and echelle formats. He has recently developed analysis tools, including an ionization code, to study the absorption line properties of simulated galaxies using the hydroART cosmological simulations. He has most recently begun research into artificial intelligence and machine learning, especially convolution neural networks, for extracting the physical properties of absorbing gas directly from quasar absorption line profiles (no Voigt profile fitting, no ionization modeling- straight from data to densities, temperatures, metallicities, and components). The challenge is the training of the neural network. If efforts are successful, thousand of high resolution absorption line systems in the data archives (VLT, KOA, HST) could be fully analyzed in less than 1% of the time it would requires humans to model the systems… which we estimate to be on the order of 50 to 100 years of human effort. For an introductory overview suitable for the public, see Introduction to QSO Absorption Lines in Cosmological Simulations.
Dr. Churchill has taught many undergraduate college level courses related to Astronomy and Physics, including “Astrophotography”, “Introduction to Astronomy”, “Life in the Universe”, “Into the Final Frontier” (a course on with focus on humanities explorations and future), and “Space Colonization”. He has also taught the graduate courses “Quasar Absorption Lines”, “Interstellar Medium”, and “Stellar Spectroscopy” (which is partially a stellar atmospheres course). Dr. Churchill is currently working hard to complete a graduate level text book entitled Cosmological Absorption Line Spectroscopy to be published in the Astrophysics Series of Cambridge University Press. His favorite non-extragalactic astrophysics topics in the class room are “Life in the Universe” and “Human Space Flight”.
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