Power of cosmic flexion as a cosmological model discriminator
Stefano Camera, Antonaldo Diaferio, and Alan F. Heavens
Accepted
Flexion is the weak lensing effect responsible for the weakly skewed and arc-like appearance of lensed galaxies. The flexion signal-to-noise ratio can be an order of magnitude larger than that of shear. For the first time, we show how this makes flexion a powerful tool for discriminating between alternative cosmological models. To this aim, we test a dynamical dark energy model and a general parameterisation of a modified-gravity cosmology. We show how the power spectrum of cosmic flexion can yield outstanding forecast constraints on these models, and how such constraining power depends on the specifics of the survey.