Publication details for Prof Richard MasseySchmidt, F., Leauthaud, A., Massey, R., Rhodes, J., George, M.R., Koekemoer, A.M., Finoguenov, A. & Tanaka, M. (2012). A detection of weak-lensing magnification using galaxy sizes and magnitudes. Astrophysical journal letters 744(2): L22.
- Publication type: Journal Article
- ISSN/ISBN: 2041-8205, 2041-8213
- DOI: 10.1088/2041-8205/744/2/L22
- Keywords: Dark matter, Gravitational lensing: weak, Large-scale structure of universe.
- Further publication details on publisher web site
- Durham Research Online (DRO) - may include full text
Author(s) from Durham
Weak lensing is commonly measured using shear through galaxy ellipticities or using the effect of magnification bias on galaxy number densities. Here, we report on the first detection of weak-lensing magnification with a new, independent technique using the distribution of galaxy sizes and magnitudes. These data come for free in galaxy surveys designed for measuring shear. We present the magnification estimator and apply it to an X-ray-selected sample of galaxy groups in the COSMOS Hubble Space Telescope survey. The measurement of the projected surface density Σ(r) is consistent with the shear measurements within the uncertainties and has roughly 40% of the signal to noise of the latter. We discuss systematic issues and challenges to realizing the potential of this new probe of weak lensing.