%0 Generic %1 bird2016statistical %A Bird, Simeon %A Garnett, Roman %A Ho, Shirley %D 2016 %K DLA statistics %T Statistical properties of damped Lyman-alpha systems from Sloan Digital Sky Survey DR12 %U http://arxiv.org/abs/1610.01165 %X 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, $dN/dX$, and the neutral hydrogen density, $Ømega_DLA$. 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. We measure a non-zero column density distribution function at $95\%$ confidence for all column densities $N_HI < 510^22$ cm$^-2$. We make the first measurements from SDSS of $dN/dX$ and $Ømega_DLA$ at $z>4$. We show that our results are insensitive to the signal-to-noise ratio of the spectra, but that there is a residual dependence on quasar redshift for $z<2.5$, which may be due to remaining systematics in our analysis.

@misc{bird2016statistical, abstract = {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 \cite{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. We measure a non-zero column density distribution function at $95\%$ confidence for all column densities $N_\mathrm{HI} < 5\times 10^{22}$ cm$^{-2}$. We make the first measurements from SDSS of $\mathrm{d}N/\mathrm{d}X$ and $\Omega_\mathrm{DLA}$ at $z>4$. We show that our results are insensitive to the signal-to-noise ratio of the spectra, but that there is a residual dependence on quasar redshift for $z<2.5$, which may be due to remaining systematics in our analysis.}, added-at = {2016-10-06T10:23:34.000+0200}, author = {Bird, Simeon and Garnett, Roman and Ho, Shirley}, biburl = {https://www.bibsonomy.org/bibtex/2357a694c3aa2f9e399c79cca928c94a0/miki}, description = {[1610.01165] Statistical properties of damped Lyman-alpha systems from Sloan Digital Sky Survey DR12}, interhash = {5b2b16295a46329d2cc3a8e89fc339d3}, intrahash = {357a694c3aa2f9e399c79cca928c94a0}, keywords = {DLA statistics}, note = {cite arxiv:1610.01165Comment: 7 pages, 6 figures, plus 6 tables of figure values. Will be submitted to MNRAS}, timestamp = {2016-10-06T10:23:34.000+0200}, title = {Statistical properties of damped Lyman-alpha systems from Sloan Digital Sky Survey DR12}, url = {http://arxiv.org/abs/1610.01165}, year = 2016 }