Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Chiba, Japan.
Phys Rev Lett. 2012 Aug 3;109(5):051301. doi: 10.1103/PhysRevLett.109.051301. Epub 2012 Jul 31.
In general relativity, the average velocity field of dark matter around galaxy clusters is uniquely determined by the mass profile. The latter can be measured through weak lensing. We propose a new method of measuring the velocity field (phase space density) by stacking redshifts of surrounding galaxies from a spectroscopic sample. In combination with lensing, this yields a direct test of gravity on scales of 1-30 Mpc. Using N-body simulations, we show that this method can improve upon current constraints on f(R) and Dvali-Gabadadze-Porrati model parameters by several orders of magnitude when applied to upcoming imaging and redshift surveys.
在广义相对论中，星系团周围暗物质的平均速度场是由质量分布唯一确定的。后者可以通过弱引力透镜测量来得到。我们提出了一种通过对光谱样本中周围星系的红移进行堆叠来测量速度场（相空间密度）的新方法。结合透镜，这可以在 1-30 Mpc 的尺度上直接检验引力。通过 N 体模拟，我们表明，当应用于即将到来的成像和红移调查时，该方法可以将对 f(R) 和 Dvali-Gabadadze-Porrati 模型参数的当前约束提高几个数量级。
