A frozen linear morphology classifier on AION-1 embeddings transfers zero-shot across telescope surveys

Parker, Lanusse, Shen et al. (2025) train a 10-way linear/softmax morphology classifier (Galaxy Zoo-10 classes) on frozen AION-1 embeddings of Legacy Survey galaxy images, encoder unmodified [parker-etal-2025-aion-1-omnimodal-foundation-model-astronomical-sciences] Applying the identical, un-fine-tuned head to Hyper Suprime-Cam images from a different telescope/filter set/pixel scale (overlapping galaxies removed to prevent leakage) yields zero-shot accuracy (84.15-85.91%) matching or exceeding native-domain training accuracy (83.95-87.16%) across three model sizes [parker-etal-2025-aion-1-omnimodal-foundation-model-astronomical-sciences] No causal intervention is performed; the paper is otherwise benchmark-dominated, with this cross-survey linear transfer the one genuine emergent-structure finding [parker-etal-2025-aion-1-omnimodal-foundation-model-astronomical-sciences]