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In the last 20 years, astronomers have come to realize that our understanding of how galaxies form and evolve must take account of the effects of interstellar dust. Dust grains tend to absorb and scatter starlight at visible wavelengths, with the result that if a galaxy contains enough dust, it can be almost entirely hidden from detection with even powerful optical telescopes. Such dusty galaxies are more commonly found at great distances (i.e., where we are seeing the universe as it was billions of years ago) than they are in the neighborhood of our own Milky Way. To understand the properties of such dusty galaxies, an important tool is the use of gravitational lensing -- a phenomenon in which the light from a distant background (dusty) galaxy is bent by the strong gravitational pull of one or more galaxies along the line of sight. A single lensed background galaxy can be stretched into multiple apparent images, making it brighter and easier to study in detail.
The mentors for this project are, respectively, an observational and a theoretical astrophysicist (Prof. Andrew Baker and Prof. Chuck Keeton, respectively). A sample of dusty galaxies that Prof. Baker has been studying includes a lensed system that is not entirely hidden by dust, and that therefore has been the subject of high-quality optical imaging with the Hubble Space Telescope -- which can be modelled using computational techniques and software developed by Prof. Keeton. By developing a lens model for this system, it will be possible to determine how much the background dusty galaxy has been magnified by, what its true ("de-lensed") appearance is, and what the properties of the lensing galaxy or galaxies are. The main goal of the project is for the student to take the lead in developing such a "lens model," in order to enable multiple scientific analyses of this sort.
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