Graduation Year


Document Type

Campus Only Senior Thesis


We study the extent to which galaxies in early overdensities enrich their surroundings by mapping the distribution of hydrogen and metals within them. We first make maps of the high-redshift (z ~ 2.5) intergalactic medium using a dense network of background star-forming galaxies and quasars that probe foreground gas in absorption. We present 3D tomographic reconstructions of the Lyman-alpha absorption field over a large volume, created using spectra from the Lyman-alpha Tomography IMACS Survey. Within this volume, we identify a sample of 25 large-scale HI overdensities that are expected to be progenitors of galaxy groups and clusters. By selecting background galaxies that lie behind each overdensity, we produce a composite absorption spectrum of the gas within a typical overdensity. In addition to Lyman-alpha, this spectrum clearly shows CIV absorption at high significance. The radial profile of CIV shows that significant absorption persists out to ~ 2 physical Mpc. We estimate the typical CIV mass in protoclusters and compare it to previous measurements of the CIV mass associated with typical galaxies. We find that we can roughly account for CIV in protoclusters arising from the halos of > 1/3 L* galaxies. These results represent the first statistical measurement of the chemical sphere of influence of high redshift overdensities.

This thesis is restricted to the Claremont Colleges current faculty, students, and staff.