Magnification of Photometric LRGs by Foreground LRGs and Clusters in SDSS

Understand

The magnification effect of gravitational lensing is a powerful probe of the distribution of matter in the universe, yet it is frequently overlooked due to the fact that its signal to noise is smaller than that of lensing shear.

• Because its systematic errors are quite different from those of shear, magnification is nevertheless an important approach with which to study the distribution of large scale structure.
• We present lensing mass profiles of spectroscopic luminous red galaxies (LRGs) and galaxy clusters determined through measurements of the weak lensing magnification of photometric LRGs in their background.
• We measure the change in detected galaxy counts as well as the increased average galaxy flux behind the lenses.