Bayesian Galaxy Asymmetry
- 1Queen’s University
- 2University of Edinburgh
- 3Inter-University Institute for Data Intensive Astronomy
Abstract
Galaxy asymmetry is an efficient way to characterize galaxy morphology in atomic hydrogen 21 cm emission detections. We propose a novel Bayesian approach to calculate the probability of an underlying squared differences asymmetry in a noisy detection. This approach has a number of advantages, including the recovery of low asymmetry values where prior noise corrections failed. More importantly, our approach provides robust uncertainties on the asymmetry, enabling a wide variety of statistical studies of galaxy populations. This method is generalized for convolved noise measures. We validate our method using a convergence test. Finally, we show how, when applied to the untargeted H I survey WALLABY, our method nearly triples the number of reliable measurements relatively to the previous state-of-the-art technique. This Bayesian approach to measure asymmetry will therefore further unlock the statistical power of widefield galaxy surveys.
Versions
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BibTeX
@article{perroncormier2026bayesian,
title = {{Bayesian Galaxy Asymmetry}},
author = {Mathieu Perron-Cormier and Kristine Spekkens and Nathan Deg and Lawrence M. Widrow and Marcin Glowacki},
journal = {The Astrophysical Journal},
year = {2026},
month = oct,
doi = {10.3847/1538-4357/aea97a},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/aea97a},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Bayesian Galaxy Asymmetry
AU - Mathieu Perron-Cormier
AU - Kristine Spekkens
AU - Nathan Deg
AU - Lawrence M. Widrow
AU - Marcin Glowacki
PY - 2026
DA - 2026/10/12
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/aea97a
UR - https://iopscience.iop.org/article/10.3847/1538-4357/aea97a
AB - Galaxy asymmetry is an efficient way to characterize galaxy morphology in atomic hydrogen 21 cm emission detections. We propose a novel Bayesian approach to calculate the probability of an underlying squared differences asymmetry in a noisy detection. This approach has a number of advantages, including the recovery of low asymmetry values where prior noise corrections failed. More importantly, our approach provides robust uncertainties on the asymmetry, enabling a wide variety of statistical studies of galaxy populations. This method is generalized for convolved noise measures. We validate our method using a convergence test. Finally, we show how, when applied to the untargeted H I survey WALLABY, our method nearly triples the number of reliable measurements relatively to the previous state-of-the-art technique. This Bayesian approach to measure asymmetry will therefore further unlock the statistical power of widefield galaxy surveys.
SN - 0004-637X
SN - 1538-4357
ER -