Detecting Multiple DLAs per Spectrum in SDSS DR12 with Gaussian Processes
Abstract
We present a revised version of our automated technique using Gaussian processes (GPs) to detect Damped Lyman- 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- 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- 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 (), and neutral hydrogen density ().
Keywords
Cite
@article{arxiv.2003.11036,
title = {Detecting Multiple DLAs per Spectrum in SDSS DR12 with Gaussian Processes},
author = {Ming-Feng Ho and Simeon Bird and Roman Garnett},
journal= {arXiv preprint arXiv:2003.11036},
year = {2020}
}
Comments
24 pages, 20 figures, plus 3 tables of figure values. Minor changes to match version published in MNRAS. Code available in https://github.com/rmgarnett/gp_dla_detection/tree/master/multi_dlas