2026 workshop program
BRAHMa: Bar Recognition And Hatching using MAchine learning
The work
Abstract
Galactic bars are fundamental components in studies of dark matter, galaxy evolution, and secular dynamics. However, current methods for measuring bar properties suffer from significant limitations. Manual and crowdsourced catalogs are not scalable to next-generation surveys, while recent machine learning (ML) approaches based on pixel-wise segmentation are computationally intensive and require complex post-processing to extract physical parameters.
In this paper, we introduce BRAHMa (Bar Recognition And Hatching using Machine Learning), a publicly available tool based on an oriented-bounding-box YOLO11x model, designed for the rapid and objective detection of galactic bars. Our model was initially trained on synthetic data, validating its efficacy before training with real data. BRAHMa was trained on bar masks from the Galaxy Zoo 3D (GZ-3D) citizen science project, utilizing images from the DESI Legacy Survey.
We address the inherent challenge of ‘ground truth’ in astronomical data by comparing GZ-3D labels with the Hoyle dataset for 586 common galaxies. This comparison reveals a baseline L1 error of 0.99 kpc, establishing a practical ‘floor’ for measurement uncertainty that no model can surpass. Our BRAHMa tool achieves an L1 error of 1.1 kpc on a large set of 3,150 galaxies from the Hoyle dataset, demonstrating performance that approaches this fundamental limit.
We further validate the model’s robustness by applying it to distinct datasets, proving its generalizability. BRAHMa provides a scalable and reliable method for bar extraction, enabling large-scale morphological studies. The tool is publicly available at https://brahma-bar-detector.netlify.app/.