A High Redshift Survey of Lyman Limit Systems
Abstract
Lyman Limit Systems (LLSs), a class of quasar absorption line system detected towards background quasars, are ubiquitous in quasar spectra and provide a crucial tool for understanding high redshift galaxy formation and evolution. At moderate neutral hydrogen (HI) column densities, 1017.5< N(HI) < 1020.3 cm-2, the LLSs are thought to trace the halos of galaxies, and thus provide constraints on the elusive interface between galaxies and the intergalactic medium. While several surveys have investigated the properties of LLSs, they have primarily focused on redshifts below z=4.5. As a complement to these previous studies, we present a survey of LLSs in a sample of twenty-six, high redshift (z>5) quasars with VLT/X-Shooter spectra. These high redshift systems unlock information about the universe during its first few gigayears. We calculate the number of systems per unit redshift, l(X), at z >4.4, extending the redshift evolution of LLSs presented in Fumagalli et al. (2015). For those systems with associated metal line absorption, we provide an estimate of the LLSs metallicity. This project was supported in part by the NSF REU grant AST-1358980 and by the Nantucket Maria Mitchell Association.
- Publication:
-
American Astronomical Society Meeting Abstracts #231
- Pub Date:
- January 2018
- Bibcode:
- 2018AAS...23135702B