Detecting Damped Lyman-$\alpha$ Absorbers with Gaussian Processes

TL;DR

This paper introduces an automated Gaussian process-based method for detecting damped Lyman-alpha absorbers in quasar spectra, aiding high-redshift galaxy formation studies with high accuracy.

Contribution

It presents a novel Gaussian process model tailored for quasar spectra and Bayesian model selection for DLA detection, scalable to large surveys.

Findings

High detection accuracy demonstrated in validation experiments.

Successfully applied to over 160,000 SDSS spectra.

Provides a comprehensive DLA catalog for further research.

Abstract

We develop an automated technique for detecting damped Lyman-$\alpha$ absorbers (DLAs) along spectroscopic lines of sight to quasi-stellar objects (QSOs or quasars). The detection of DLAs in large-scale spectroscopic surveys such as SDSS-III sheds light on galaxy formation at high redshift, showing the nucleation of galaxies from diffuse gas. We use nearly 50 000 QSO spectra to learn a novel tailored Gaussian process model for quasar emission spectra, which we apply to the DLA detection problem via Bayesian model selection. We propose models for identifying an arbitrary number of DLAs along a given line of sight. We demonstrate our method's effectiveness using a large-scale validation experiment, with excellent performance. We also provide a catalog of our results applied to 162 858 spectra from SDSS-III data release 12.