Cause of the anomalous MRLens tomographic performance

Determine why the Multi-Resolution method for gravitational Lensing (MRLens) performs worse under the tomographic approach and differs substantially from the other detection methods using the same three overlapping redshift bins, including whether the method for combining detections from each redshift bin is responsible.

Background

The paper evaluates weak-lensing galaxy-cluster detection methods using several tomographic strategies that divide source galaxies into redshift bins. MRLens, like J04, S96, TANH, and W234, uses three overlapping redshift bins, but its tomographic performance declines relative to its integrated-approach performance and differs markedly from the other methods using the same binning scheme.

The authors explicitly state that they do not have a clear explanation for this discrepancy and identify the procedure used to combine detections across redshift bins as a possible cause. Establishing the source of this behaviour is necessary for defining reliable tomographic processing strategies for Euclid weak-lensing data.

References

We do not have a clear answer as to why MRLens performance worsens and differs so much from those of the other methods that use the same three overlapping redshift bins, but it may be due to the way the detections made in each bin were combined.

— Euclid: Galaxy cluster detection through the weak lensing effect - algorithm assessment and selection  (2609.20571 - Manjón-García et al., 17 Sep 2026) in Appendix, Section “Conclusions on the tomographic approaches”