Finding Galaxies in the Shadows of Quasars with Gaussian Processes
Roman Garnett, Shirley Ho, Jeff Schneider · 2015
We develop an automated technique for detecting damped Lyman- ˛ absorbers (DLAs) along spec-troscopic sightlines to quasi-stellar objects (QSOs or quasars). The detection of DLAs in large-scale spectroscopic surveys such as SDSS–III is critical to address outstanding cosmological questions, such as the nature of galaxy formation. We use nearly 50 000 QSO spectra to learn a tailored Gaus-sian process model for quasar emission spectra, which we apply to the DLA detection problem via Bayesian model selection. We demonstrate our method’s effectiveness with a large-scale vali-dation experiment on over 100 000 spectra, with excellent performance. 1.