Galaxy, Star, and Planet Formation

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Many people, my self very much included, wonder how the universe, and the galaxies, stars and planets it holds, came about, and how we fit into this larger picture. I propose to study the origin and evolution of galaxy clusters, galaxies, stars, and planets. I am also interested in what astronomical observations can tell us about dark matter, which is believed to hold galaxies and galaxy clusters together, and about dark energy, which is believed to be pushing galaxies away from each other, i.e., accelerating the expansion of spacetime.*** In work carried out over the last five years, I and my coworkers have proposed that most planets form in place, in dust and rock rich disks around young stars. Roughly half of these closely packed planetary systems are stable for eons, while the rest of the systems were unstable, and appear as single transiting planets. I aim to identify the mechanism leading to the instability; if I succeed, we will learn more about the initial conditions for planet formation.*** Over the same time period I have worked extensively on earlier stages, when the stars themselves acquired most of their mass. It is known that most stars, including our own Sun, form in star clusters. My work has shown that the total stellar mass in a cluster grows in proportion to the square of the time; individual stars grow in mass more nearly in direct proportion to the time. My group will carry out simulations to see how the fuel for star formation is depleted, and how the proto-stellar disk mass evolves in time.*** Moving up in scale, I will continue work on galaxy formation. I have been involved in a collaboration using simulations to model galaxies starting from small fluctuations in density soon after the big bang up to fully formed objects today. We have successfully predicted the stellar masses of galaxies in dark matter halos with a large range of masses; we were the first group able to do so. The next step is to test the model galaxies extensively, for example by comparing the amount of gas in the regions around the simulated galaxies to that seen in observations of both nearby and distant galaxies. *** On yet larger scales, I am leading the Canadian consortium that is one of the major partners in the effort to build CCAT Prime, a six meter telescope that will be used to map the distribution of matter on large scales. CCAT Prime will be ideal for Stage IV Cosmic Microwave Background work, the next generation effort to measure the fundamental parameters of the Universe. In support of this effort, I will undertake, using the galaxy simulations just mentioned, forecast efforts to help with the design of the telescope.