A detection of weak-lensing magnification using galaxy sizes and magnitudes

Schmidt, F.; Leauthaud, A.; Massey, R.; Rhodes, J.; George, M.R.; Koekemoer, A.M.; Finoguenov, A.; Tanaka, M.

doi:10.1088/2041-8205/744/2/l22

A detection of weak-lensing magnification using galaxy sizes and magnitudes

Schmidt, F.; Leauthaud, A.; Massey, R.; Rhodes, J.; George, M.R.; Koekemoer, A.M.; Finoguenov, A.; Tanaka, M.

Authors

F. Schmidt

A. Leauthaud

Professor Richard Massey r.j.massey@durham.ac.uk
Professor

J. Rhodes

M.R. George

A.M. Koekemoer

A. Finoguenov

M. Tanaka

Abstract

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.

Citation

Schmidt, F., Leauthaud, A., Massey, R., Rhodes, J., George, M., Koekemoer, A., …Tanaka, M. (2012). A detection of weak-lensing magnification using galaxy sizes and magnitudes. Astrophysical Journal Letters, 744(2), Article L22. https://doi.org/10.1088/2041-8205/744/2/l22

Journal Article Type	Article
Publication Date	Jan 10, 2012
Deposit Date	Jan 31, 2012
Publicly Available Date	Feb 12, 2015
Journal	Astrophysical Journal Letters
Print ISSN	2041-8205
Electronic ISSN	2041-8213
Publisher	American Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	744
Issue	2
Article Number	L22
DOI	https://doi.org/10.1088/2041-8205/744/2/l22
Keywords	Dark matter, Gravitational lensing: weak, Large-scale structure of universe.