Combining cosmic shear data with correlated photo-$z$ uncertainties: constraints from DESY1 and HSC-DR1
ArXiv 2210.13434 (2022)
Impact of the Universe's expansion rate on constraints on modified growth of structure
Physical Review D American Physical Society 106:8 (2022) 83523
Abstract:
In the context of modified gravity, at the linear level, the growth of structure in the Universe will be affected by modifications to the Poisson equation and by the background expansion rate of the Universe. It has been shown that these two effects lead to a degeneracy which must be properly accounted for if one is to place reliable constraints on new forces on large scales or, equivalently, modifications to general relativity. In this paper we show that current constraints are such that assumptions about the background expansion have little impact on constraints on modifications to gravity. We do so by considering the background of a flat, Λ cold dark matter universe, a universe with a more general equation of state for the dark energy, and finally, a general, model-independent, expansion rate. We use Gaussian processes to model modifications to Poisson's equation and, in the case of a general expansion rate, to model the redshift-dependent Hubble rate. We identify a degeneracy between modifications to Poisson's equation and the background matter density, ωM, which can only be broken by assuming a model-dependent expansion rate. We show that, with current data, the constraints on modifications to the Poisson equation via measurements of the growth rate range between 10-20% depending on the strength of our assumptions on the Universe's expansion rate.Constraining the physics of star formation from CIB-cosmic shear cross-correlations
ArXiv 2209.05472 (2022)
The impact of the Universe's expansion rate on constraints on modified growth of structure
ArXiv 2207.09896 (2022)
The star formation history in the last 10 billion years from CIB cross-correlations
ArXiv 2206.15394 (2022)