Beyond traditional emission-line diagnostics: using autoencoders to uncover active galactic nuclei in DESI spectra

arXiv:2607.07329 · astro-ph.GA · Submitted 2026-07-08 · Read on arXiv

J. A. Alcolea, M. Siudek, M. Eriksen, M. Mezcua, R. Pucha, S. Juneau, S. Gontcho A Gontcho, S. Panda, J. Aguilar, S. Ahlen, D. Bianchi, A. Brodzeller, D. Brooks, F. J. Castander, T. Claybaugh, A. Cuceu, A. de la Macorra, B. Dey, P. Doel, S. Ferraro, A. Font-Ribera, J. E. Forero-Romero, E. Gaztañaga, G. Gutierrez, C. Hahn, H. K. Herrera-Alcantar, D. Joyce, R. Kehoe, D. Kirkby, T. Kisner, A. Kremin, O. Lahav, C. Lamman, M. Landriau, L. Le Guillou, A. Meisner, R. Miquel, J. Moustakas, S. Nadathur, W. Percival, F. Prada, I. Pérez-Ràfols, G. Rossi, E. Sanchez, E. Schlafly, D. Schlegel, M. Schubnell, J. Silber, D. Sprayberry, G. Tarlé, B. A. Weaver, H. Zou

astro-ph.GA

Submitted: 2026-07-08

License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Terminology

• AGN — 255× in this paper · explained in 1 episode
• Latent Space — 39× in this paper · explained in 7 episodes
• Accuracy — 20× in this paper · explained in 1 episode
• AUC — 16× in this paper · explained in 2 episodes
• Latent Representation — 7× in this paper · explained in 2 episodes
• Representation Learning — 6× in this paper · explained in 2 episodes
• Loss Function — 4× in this paper · explained in 2 episodes
• Robustness — 4× in this paper · explained in 5 episodes
• Active Galactic Nuclei (AGN) — 3× in this paper · explained in 1 episode
• Clustering — 3× in this paper · explained in 2 episodes
• Interpretability — 3× in this paper · explained in 15 episodes
• Latent Representations — 3× in this paper · explained in 3 episodes
• National Science Foundation — 3× in this paper
• Consistency — 2× in this paper · explained in 3 episodes
• Dark Energy Spectroscopic Instrument — 2× in this paper
• Degeneracy — 2× in this paper · explained in 3 episodes
• Department of Energy — 2× in this paper
• F1 Score — 2× in this paper · explained in 3 episodes
• Metallicity — 2× in this paper · explained in 3 episodes
• Receiver Operating Characteristic — 2× in this paper
• Uniform Manifold Approximation and Projection — 2× in this paper
• AGN Feedback — 1× in this paper · explained in 1 episode
• Accretion Flows — 1× in this paper · explained in 1 episode
• Area Under the Curve — 1× in this paper
• Benchmark — 1× in this paper · explained in 2 episodes
• Feature Extraction — 1× in this paper · explained in 2 episodes
• Fidelity — 1× in this paper · explained in 2 episodes
• Semi-supervised Learning — 1× in this paper · explained in 4 episodes
• Society of Photo-Optical Instrumentation Engineers — 1× in this paper
• Trace — 1× in this paper · explained in 2 episodes
• Transformer — 1× in this paper · explained in 2 episodes

Sources

• Radio Galaxy Zoo: Leveraging latent space representations from variational autoencoder
• The DESI Experiment Part II: Instrument Design
• Data Release 1 of the Dark Energy Spectroscopic Instrument
• Identifying Anomalous DESI Galaxy Spectra with a Variational Autoencoder
• Unsupervised classification reveals new evolutionary pathways
• The VIMOS Public Extragalactic Redshift Survey (VIPERS). Unsupervised classification with photometric redshifts: a method to accurately classify large galaxy samples without spectroscopic information

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