astronolan/hubble-anomaly-match

Hubble Anomaly

This dataset contains 818,347 HST ACS/WFC F814W cutouts assembled from a 77,651,429-row Hubble Source Catalog v3 extended-source pull, associated with Hubble Advanced Products, and deduplicated to a minimum separation of 10 arcsec.

Anomaly labels and types come from O'Ryan, D. & Gómez, P. (2025), Identifying astrophysical anomalies in 99.6 million source cutouts from the Hubble Legacy Archive using AnomalyMatch, Astronomy & Astrophysics, 704, A227. We used the 1,176-row DOR_PG+2025_anomalies.csv catalogue from the authors' Zenodo release v1.6.0.

Each AnomalyMatch coordinate was matched to its nearest parent-catalogue source within 3 arcsec, yielding 583 unique matched sources. The remaining 817,764 rows are the other retained parent-catalogue sources. anomalymatch_anomaly marks those 583 matches. anomalymatch_type contains the catalogue's Classification value (for example, agn) and is null for unmatched rows. If multiple catalogue entries map to one deduplicated HST source, the classification from the closest coordinate is used.

Images were copied byte-for-byte from the source HDF5 as 150 x 150 grayscale JPEGs, without resizing or re-encoding. Catalogue metadata were joined by Hubble Source Catalog SourceID from the companion Parquet table. The underlying HST observations and measurements were obtained from MAST.

The dataset is split 60% / 20% / 20% into train, test, and val, using random seed 44 and stratification by anomalymatch_anomaly. Every source appears in exactly one split. Unmatched rows are unlabeled, rather than confirmed non-anomalous galaxies.

Split	Images	AnomalyMatch matches
train	491,008	350
test	163,670	117
val	163,669	116

Every Parquet shard is at most 200 MB (200,000,000 bytes). The full input uses the 11,529-product HAP inventory frozen on 2026-08-28. Spatial suppression over the expanded catalogue can change which detections survive in previously covered fields; this release is not simply an append to the earlier 20,000-image benchmark. Images were reconstructed from public MAST FITS products during this build.

provenance.json records the release inputs and build details. Reference associations are provided under reference/.

Photometry

f814w_mag is HSC v3 DetailedCatalog MagAuto, the Source Extractor estimate of total F814W brightness in AB magnitudes. ci is HSC CI, the concentration index normalized by detector and filter, based on the difference between small and large aperture magnitudes. These are catalogue measurements from the exact ACS/WFC F814W observation used for each cutout, not measurements of the JPEG. Both columns were freshly queried for every retained source, including every AnomalyMatch match. The join uses SourceID, MatchID, and ImageName, with Det='Y', Detector='ACS/WFC', and Filter='F814W'. No historical photometry file is needed. Null magnitudes indicate missing catalogue measurements; quality flags should be considered when using the photometry.

HSC field definitions. The query and its provenance are under reference/hsc_photometry/.