Finding Stellar Streams in the Milky Way with CWoLa

These datasets are designed to accompany the paper Weakly-Supervised Anomaly Detection in the Milky Way by M. Pettee, S. Thanvantri, B. Nachman, D. Shih, M. R. Buckley, and J. H. Collins (https://arxiv.org/abs/2305.03761). They illustrate how the Classification Without Labels (CWoLa) technique can be applied in the search for localized anomalies -- in this case, cold stellar streams -- in the Gaia DR2 dataset. We consider both simulated stellar streams and the known stream GD-1. The codebase is located at https://github.com/hep-lbdl/GaiaCWoLa. 

These datasets are all formatted as Pandas DataFrames, and can be loaded using `df = pd.read_hdf(file)`. Datasets ending in `*_cwola.h5*` indicate that CWoLa has been applied to the stars in that dataset. For this analysis, we consider circular "patches" of the sky of radius 15° from the Gaia DR2 dataset. 

Columns include: 

• μ_δ: Proper motion (declination)
• μ_α: Proper motion (right ascension)
• δ: Declination
• α: Right ascension
• α_wrapped: Right ascension, wrapped such that all angles are > 0 
• b-r: Color
• g: Magnitude
• ϕ: Rotated & centered right ascension 
• λ: Rotated & centered declination 
• μ_ϕcosλ: Rotated & centered proper motion (right ascension) 
• μ_λ: Rotated & centered proper motion (declination) 
• stream: Boolean label (True if part of ground truth labeling for GD-1)
• patch_id: Index of the 21 patches of the GD-1 scan
• nn_score: CWoLa classifier score (0 = more background-like; 1 = more signal=like)
• 5d_distance: For the potential GD-1 member candidates, the 5D Euclidean distance to the nearest labeled star

Files include:

• gd1_1_patch.h5
  • Example patch of GD-1
• gd1_21_patches_cwola.h5
  • Results from applying CWoLa to the 21 patches spanning GD-1 
• promising_stars.h5
  • A list of stars identified by CWoLa that do not belong to the labeled GD-1 stream catalogue, but are close in 5D Euclidean space to labeled stars. Ordered in descending order by CWoLa classifier score. 
• scan_bump_cwola.h5
  • An example of how to apply CWoLa in a scan where the stream location is unknown
• scan_no_bump_cwola.h5
  • An example of how to apply CWoLa in a scan where the stream location is unknown
• simulated_100_patches.h5
  • Results from applying CWoLa to 100 simulated streams 
• simulated_patch.h5
  • A full simulated stream 
• simulated_patch_cwola.h5
  • Results from applying CWoLa to the example simulated stream

To recreate the full scan across GD-1, one would need to use the original 21 patches of Gaia DR2 located at 10.5281/zenodo.7897935 that were constructed for arXiv:2104.12789 [astro-ph.GA). GD-1 labels were derived from 10.5281/zenodo.1295543.