Model-Free Multi-Probe Lensing Reconstruction of Cluster Mass Profiles

Understand

Lens magnification by galaxy clusters induces characteristic spatial variations in the number counts of background sources, amplifying their observed fluxes and expanding the area of sky, the net effect of which, known as magnification bias, depends on the intrinsic faint-end slope of the source luminosity function.

• The bias is strongly negative for red galaxies, dominated by the geometric area distortion, whereas it is mildly positive for blue galaxies, enhancing the blue counts toward the cluster center.
• We generalize the Bayesian approach of Umetsu et al.
• for reconstructing projected cluster mass profiles, by incorporating multiple populations of background sources for magnification bias measurements and combining them with complementary lens distortion measurements, effectively breaking the mass-sheet degeneracy and improving the statistical precision of cluster mass measurements.