Robustness to non-representative spectroscopic selection

Evaluate how the probabilistic autoencoder galaxy-population prior performs when the spectroscopic training sample is selected under a Rubin-like photometric survey selection and progressively subjected to magnitude cuts that reduce its representativeness.

Background

The analysis assumes that the spectroscopic calibration sample is representative of the photometric weak-lensing sample and uses a 4C3R2-like magnitude limit. The authors note that real weak-lensing samples are generally fainter than spectroscopic calibration samples, so selection effects may bias the learned prior and the resulting redshift distributions.

The paper proposes a concrete unresolved test: repeat the analysis with a Rubin-like selection and impose increasingly restrictive magnitude cuts on the spectroscopic training data. This would quantify how the method's photometric-redshift calibration accuracy degrades as the training sample becomes less representative.

References

A natural test of this robustness, which we leave to future work, is to repeat the analysis under a Rubin-like selection rather than the 4C3R2-like spectroscopic sample used here, and to progressively impose more magnitude cuts on the spectroscopic training set to quantify how performance degrades as representativeness decreases.

— Data-driven Galaxy Population Prior for Photometric Redshifts  (2609.26594 - Frediani et al., 22 Sep 2026) in Section 4, Discussion