Enhancing Lyα Emitter Identification in HETDEX with a Convolutional Neural Network

Fuente: arXiv
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Autores principales: Mukae, Shiro, Cooper, Erin Mentuch, Gebhardt, Karl, Davis, Dustin, House, Lindsay R., Qezlou, Mahdi, Muñoz, Julian B., Saito, Shun, Farrow, Daniel J., Gronwall, Caryl, Schneider, Donald P., Gawiser, Eric
Formato: Preprint
Publicado: 2026
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author Mukae, Shiro
Cooper, Erin Mentuch
Gebhardt, Karl
Davis, Dustin
House, Lindsay R.
Qezlou, Mahdi
Muñoz, Julian B.
Saito, Shun
Farrow, Daniel J.
Gronwall, Caryl
Schneider, Donald P.
Gawiser, Eric
author_facet Mukae, Shiro
Cooper, Erin Mentuch
Gebhardt, Karl
Davis, Dustin
House, Lindsay R.
Qezlou, Mahdi
Muñoz, Julian B.
Saito, Shun
Farrow, Daniel J.
Gronwall, Caryl
Schneider, Donald P.
Gawiser, Eric
contents We present a deep learning framework to enhance the identification of Ly$α$ emitters (LAEs) in the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), an untargeted spectroscopic survey of LAEs at $1.9 < z < 3.5$ without imaging pre-selection. We primarily address the low signal-to-noise ratio (S/N) regime ($4.8 \leq \mathrm{S/N} \leq 5.5$), where LAE candidates suffer from substantial noise contamination. To distinguish LAE candidates from artifacts and sky residuals, we employ a convolutional neural network (CNN) trained on two-dimensional spectral images of single emission lines. The training sample is constructed from the HETDEX COSMOS catalog, with external validation from ancillary observations and our participatory science project, \textit{Dark Energy Explorers}. For small-format, low-resolution spectroscopic data, the model achieves a balanced accuracy, precision, and recall of $94.1\%$, $97.5\%$, and $97.5\%$, respectively, in the high-S/N regime ($\mathrm{S/N}>5.5$), and $85.1\%$, $78.2\%$, and $84.4\%$ in the low-S/N regime. Using HETDEX LAEs independently identified by DESI spectroscopy, the model recovers $99\%$ and $93\%$ of the high- and low-S/N LAEs, respectively. Visual attribution indicates that the CNN attends to smooth, spatially extended central emission in true positives and to irregular or noisy features in true negatives. Applied to the full HETDEX catalog, the CNN enables an S/N threshold down to 4.8 by suppressing spurious spikes across $z\sim 1.9$--$2.5$ in the redshift distribution. Our approach facilitates HETDEX cosmological analyses by mitigating false positives in galaxy clustering and highlights the value of domain-specific deep learning for refining low-S/N spectroscopic identification in untargeted surveys.
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id arxiv_https___arxiv_org_abs_2604_12414
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Enhancing Lyα Emitter Identification in HETDEX with a Convolutional Neural Network
Mukae, Shiro
Cooper, Erin Mentuch
Gebhardt, Karl
Davis, Dustin
House, Lindsay R.
Qezlou, Mahdi
Muñoz, Julian B.
Saito, Shun
Farrow, Daniel J.
Gronwall, Caryl
Schneider, Donald P.
Gawiser, Eric
Astrophysics of Galaxies
Instrumentation and Methods for Astrophysics
We present a deep learning framework to enhance the identification of Ly$α$ emitters (LAEs) in the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX), an untargeted spectroscopic survey of LAEs at $1.9 < z < 3.5$ without imaging pre-selection. We primarily address the low signal-to-noise ratio (S/N) regime ($4.8 \leq \mathrm{S/N} \leq 5.5$), where LAE candidates suffer from substantial noise contamination. To distinguish LAE candidates from artifacts and sky residuals, we employ a convolutional neural network (CNN) trained on two-dimensional spectral images of single emission lines. The training sample is constructed from the HETDEX COSMOS catalog, with external validation from ancillary observations and our participatory science project, \textit{Dark Energy Explorers}. For small-format, low-resolution spectroscopic data, the model achieves a balanced accuracy, precision, and recall of $94.1\%$, $97.5\%$, and $97.5\%$, respectively, in the high-S/N regime ($\mathrm{S/N}>5.5$), and $85.1\%$, $78.2\%$, and $84.4\%$ in the low-S/N regime. Using HETDEX LAEs independently identified by DESI spectroscopy, the model recovers $99\%$ and $93\%$ of the high- and low-S/N LAEs, respectively. Visual attribution indicates that the CNN attends to smooth, spatially extended central emission in true positives and to irregular or noisy features in true negatives. Applied to the full HETDEX catalog, the CNN enables an S/N threshold down to 4.8 by suppressing spurious spikes across $z\sim 1.9$--$2.5$ in the redshift distribution. Our approach facilitates HETDEX cosmological analyses by mitigating false positives in galaxy clustering and highlights the value of domain-specific deep learning for refining low-S/N spectroscopic identification in untargeted surveys.
title Enhancing Lyα Emitter Identification in HETDEX with a Convolutional Neural Network
topic Astrophysics of Galaxies
Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2604.12414