We present high signal-to-noise galaxy-galaxy lensing measurements of the BOSS CMASS sample using 250 square degrees of weak lensing data from CFHTLenS and CS82. We compare this signal with predictions from mock catalogs trained to match observables including the stellar mass function and the projected and two dimensional clustering of CMASS. We show that the clustering of CMASS, together with standard models of the galaxy-halo connection, robustly predicts a lensing signal that is 20-40% larger than observed. Detailed tests show that our results are robust to a variety of systematic effects. Lowering the value of S8=σ8Ωm/0.3 compared to Planck2015 reconciles the lensing with clustering. However, given the scale of our measurement (r<10h−1 Mpc), other effects may also be at play and need to be taken into consideration. We explore the impact of baryon physics, assembly bias, massive neutrinos, and modifications to general relativity on ΔΣ and show that several of these effects may be non-negligible given the precision of our measurement. Disentangling cosmological effects from the details of the galaxy-halo connection, the effects of baryons, and massive neutrinos, is the next challenge facing joint lensing and clustering analyses. This is especially true in the context of large galaxy samples from Baryon Acoustic Oscillation surveys with precise measurements but complex selection functions.
@article{arxiv.1611.08606,
title = {Lensing is Low: Cosmology, Galaxy Formation, or New Physics?},
author = {Alexie Leauthaud and Shun Saito and Stefan Hilbert and Alexandre Barreira and Surhud More and Martin White and Shadab Alam and Peter Behroozi and Kevin Bundy and Jean Coupon and Thomas Erben and Catherine Heymans and Hendrik Hildebrandt and Rachel Mandelbaum and Lance Miller and Bruno Moraes and Maria E. S. Pereira and Sergio A. Rodriguez-Torres and Fabian Schmidt and Huan-Yuan Shan and Matteo Viel and Francisco Villaescusa-Navarro},
journal= {arXiv preprint arXiv:1611.08606},
year = {2017}
}