Statistical properties of damped Lyman-alpha systems from Sloan Digital Sky Survey DR12

Understand

We present new estimates for the statistical properties of damped Lyman-$\alpha$ absorbers (DLAs).

• We compute the column density distribution function at $z>2$, the line density, $\mathrm{d}N/\mathrm{d}X$, and the neutral hydrogen density, $\Omega_\mathrm{DLA}$.
• Our estimates are derived from the DLA catalogue of Garnett 2016, which uses the SDSS-III DR12 quasar spectroscopic survey.
• This catalogue provides a probability that a given spectrum contains a DLA, allowing us to use even the noisiest data without biasing our results and thus substantially increase our sample size.