Cosmoparticle Initiative


From camera to cosmology with LSST weak lensing magnification

Student: Constance Mahony

First supervisors: Benjamin Joachimi (Astro), Andreas Korn (HEP)

Second supervisor: Hiranya Peiris (Astro)

Entry year: 2016
Completed: October 2020

Mirror with clouds…

Project description: Weak gravitational lensing by the large-scale structure of the Universe is one of the key cosmological probes in forthcoming large galaxy surveys. Usually, the signal is detected through the minute coherent distortions in millions of faint galaxy images caused by the lensing effect. However, gravitational lensing can also make galaxies appear fainter or brighter via gravitational magnification, and such a signal is traceable even for very faint, small, and distant galaxies. That makes magnification particularly interesting for the Large Synoptic Survey Telescope (LSST), the deepest wide-angle galaxy survey ever to be undertaken. The goal of this project is to develop the science case for weak lensing magnification with the LSST, determining its power to constrain the cosmological model, building an analysis pipeline, and characterising potential obstacles to a clean measurement from the light collection in the camera, through the electronic recording of the images all the way to the cosmological interpretation.

Funding: IMPACT / Perren / Spreadbury