Despite its continued observational successes, there is a persistent (and growing) interest in
extending cosmology beyond the standard model, Λ CDM. This is motivated by a range of …

We review the effect of the formation of nonlinear structures on the expansion rate, spatial
curvature, and light propagation in the universe, focusing on the possibility that this effect …

The disagreement between low-and high-redshift measurements of the Hubble parameter is
emerging as a serious challenge to the standard model of cosmology. We develop a …

We propose an effective model to describe the bias induced on cosmological observables
by Laniakea, the gravitational supercluster hosting the Milky Way, which was defined using …

No. In a number of papers, Green and Wald argue that the standard FLRW model
approximates our Universe extremely well on all scales, except close to strong-field …

We investigate realistic models of compact objects, focusing on neutron and strange stars,
composed by dense matter and dark energy in the form of a simple fluid or scalar field …

We present a new N-body code, gevolution, for the evolution of large scale structure in the
Universe. Our code is based on a weak field expansion of General Relativity and calculates …

We present a new massively parallel code for N-body and cosmological hydrodynamical
simulations of modified gravity models. The code employs a multigrid-accelerated Newton …

The heliocentric redshifts (z hel) reported for 150 type Ia supernovae in the Pantheon
compilation are significantly discrepant from their corresponding values in the JLA …

Assuming the universe is spatially homogeneous on the largest scales lays the foundation
for almost all cosmology. This idea is based on the Copernican Principle, that we are not at a …