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arXiv · 2003.11036

Detecting Multiple DLAs per Spectrum in SDSS DR12 with Gaussian Processes

Ming-Feng Ho·Simeon Bird·Roman Garnett
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Abstract

We present a revised version of our automated technique using Gaussian processes (GPs) to detect Damped Lyman-$α$ absorbers (DLAs) along quasar (QSO) sightlines. The main improvement is to allow our Gaussian process pipeline to detect multiple DLAs along a single sightline. Our DLA detections are regularised by an improved model for the absorption from the Lyman-$α$ forest which improves performance at high redshift. We also introduce a model for unresolved sub-DLAs which reduces mis-classifications of absorbers without detectable damping wings. We compare our results to those of two different large-scale DLA catalogues and provide a catalogue of the processed results of our Gaussian process pipeline using 158 825 Lyman-$α$ spectra from SDSS data release 12. We present updated estimates for the statistical properties of DLAs, including the column density distribution function (CDDF), line density ($dN/dX$), and neutral hydrogen density ($Ω_{\textrm{DLA}}$).

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Ming-Feng Ho, Simeon Bird, Roman Garnett. 2020-06-19. Detecting Multiple DLAs per Spectrum in SDSS DR12 with Gaussian Processes. https://doi.org/10.1093/mnras%2Fstaa1806

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