{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/fully-probabilistic-quasar-continua","title":"Fully probabilistic quasar continua predictions near Lyman-α with conditional neural spline flows","arxiv_id":"2006.00615","date":"2020-05-31","proceeding":null,"authors":["David M. Reiman","John Tamanas","J. Xavier Prochaska","Dominika Ďurovčíková"],"abstract":"Measurement of the red damping wing of neutral hydrogen in quasar spectra provides a probe of the epoch of reionization in the early Universe. Such quantification requires precise and unbiased estimates of the intrinsic continua near Lyman-$\\alpha$ (Ly$\\alpha$), a challenging task given the highly variable Ly$\\alpha$ emission profiles of quasars. Here, we introduce a fully probabilistic approach to intrinsic continua prediction. We frame the problem as a conditional density estimation task and explicitly model the distribution over plausible blue-side continua ($1190\\ \\unicode{xC5} \\leq \\lambda_{\\text{rest}} < 1290\\ \\unicode{xC5}$) conditional on the red-side spectrum ($1290\\ \\unicode{xC5} \\leq \\lambda_{\\text{rest}} < 2900\\ \\unicode{xC5}$) using normalizing flows. Our approach achieves state-of-the-art precision and accuracy, allows for sampling one thousand plausible continua in less than a tenth of a second, and can natively provide confidence intervals on the blue-side continua via Monte Carlo sampling. We measure the damping wing effect in two $z>7$ quasars and estimate the volume-averaged neutral fraction of hydrogen from each, finding $\\bar{x}_\\text{HI}=0.304 \\pm 0.042$ for ULAS J1120+0641 ($z=7.09$) and $\\bar{x}_\\text{HI}=0.384 \\pm 0.133$ for ULAS J1342+0928 ($z=7.54$).","url_abs":"https://arxiv.org/abs/2006.00615v2","url_pdf":"https://arxiv.org/pdf/2006.00615v2.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"abstracts"},"code_links":[{"paper_slug":"fully-probabilistic-quasar-continua","repo_url":"https://github.com/davidreiman/spectre","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":1,"framework":"pytorch","reach":{"status":"ok"}},{"paper_slug":"fully-probabilistic-quasar-continua","repo_url":"https://github.com/jtamanas/mssm","is_official":0,"mentioned_in_paper":0,"mentioned_in_github":1,"framework":"jax","reach":{"status":"ok"}}],"tasks":[{"task_slug":"density-estimation","task_name":"Density Estimation"}],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"atlas_url":"https://app.syntology.ai/?focus=2006.00615","mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}