Speaker
Description
The Lyman-alpha forest—the absorption signature of intergalactic hydrogen in the spectra of quasars and galaxies—is one of the most precise tools for quantifying the matter distribution in the distant universe. While the forest has been used for decades to constrain the mass of a warm dark matter particle, it can also test a broader class of dark matter models that modify structure on small scales. A key limitation has been that most Lyman-alpha forest measurements use absorption along isolated sight lines, making the forest a powerful but largely 1D probe. I will discuss recent efforts to expand the forest into a 3D probe and to use it to map the matter distribution at redshifts z~2-3. Although these nascent 3D observations are not yet powerful enough to constrain dark matter models, they are beginning to provide insights into astrophysical processes that must be understood to make full use of the forest, while previewing more powerful future surveys.