The relation between stellar mass and weak lensing signal around   galaxies: Implications for MOND
  We study the amplitude of the weak gravitational lensing signal as a function of stellar mass around a sample of relatively isolated galaxies. This selection of lenses simplifies the interpretation of the observations, which consist of data from the Red- sequence Cluster Survey and the Sloan Digital Sky Survey. We find that the amplitude of the lensing signal as a function of stellar mass is well described by a power law with a best fit slope \alpha= 0.74 \pm 0.08. This result is inconsistent with Modified Newtonian Dynamics, which predicts \alpha = 0.5 (we find \alpha > 0.5 with 99.7% confidence). As a related test, we determine the MOND mass-to-light ratio as a function of luminosity. Our results require dark matter for the most luminous galaxies (L >=10^11 L_sun). We rule out an extended halo of gas or active neutrinos as a way of reconciling our findings with MOND. Although we focus on a single alternative gravity model, we note that our results provide an important test for any alternative theory of gravity. 
Lanlan Tian (1), Henk Hoekstra (1), Hongsheng Zhao (2) (1. UVIC, CA 2.   U. of St Andrews, UK)