Related papers: Structure Formation With a Long-Range Scalar Dark …
I show that the predicted densities of the inner dark matter halos in LCDM models of structure formation appear to be higher than estimates from real galaxies and constraints from dynamical friction on bars. This inconsistency would not be…
(Abridged) We conduct a series of high-resolution, dissipationless N-body simulations to investigate the cumulative effect of substructure mergers onto thin disk galaxies in the context of the LCDM paradigm of structure formation. Our…
The dark energy plus cold dark matter ($\Lambda$CDM) cosmological model has been a demonstrably successful framework for predicting and explaining the large-scale structure of Universe and its evolution with time. Yet on length scales…
We investigate the characteristic modifications in the evolving cosmological perturbations when dark energy interacts with dust-like matter, causing the latter's background energy density fall off with time faster than usual. Focusing in…
A suitable nonlinear interaction between dark matter with an energy density $\rho_{M}$ and dark energy with an energy density $\rho_{X}$ is known to give rise to a non-canonical scaling $\rho_{M} \propto \rho_{X}a^{-\xi}$ where $\xi$ is a…
We investigate cosmological implications of an energy density contribution arising by elastic dark matter self-interactions. Its scaling behaviour shows that it can be the dominant energy contribution in the early universe. Constraints from…
A long-range force acting only between nonbaryonic particles would be associated with a large violation of the weak equivalence principle. We explore cosmological consequences of this idea, which we label ReBEL (daRk Breaking Equivalence…
A large amount of observations have constrained cosmological parameters and the initial density fluctuation spectrum to a very high accuracy. However, cosmological parameters change with time and the power index of the power spectrum varies…
A standard theoretical paradigm for the formation of large-scale structure in the distribution of galaxies has now been established, based on the gravitational instability of cold dark matter in a background cosmology dominated by vacuum…
We study models of late-time cosmic acceleration in terms of scalar-tensor theories generalized to include a certain class of non-linear derivative interaction of the scalar field. The non-linear effect suppress the scalar-mediated force at…
We introduce a new class of interacting dark sector models that couple the intrinsic entropy of dark matter to scalar field dark energy. Using the Lagrangian formulation for relativistic perfect fluids, we construct consistent covariant…
Astrophysical observations spanning dwarf galaxies to galaxy clusters indicate that dark matter (DM) halos are less dense in their central regions compared to expectations from collisionless DM N-body simulations. Using detailed fits to DM…
Lambda- Cold Dark Matter (LambdaCDM) has been successful at explaining the large-scale structures in the universe but faces severe issues on smaller scales when compared to observations. Introducing self-interactions between dark matter…
Cosmological models involving an interaction between dark matter and dark energy have been proposed in order to solve the so-called coincidence problem. Different forms of coupling have been studied, but there have been claims that…
The success of the Lambda-CDM model on large scales does not extend down to galaxy scales. We list a dozen problems of the dark matter hypothesis, some of which arise in specific models for the formation of structure in the universe, while…
Complimenting recent work on the effective field theory of cosmological large scale structures, here we present detailed approximate analytical results and further pedagogical understanding of the method. We start from the collisionless…
By means of a semi-analytic model of galaxy formation, we show how the local observed relation between age and galactic stellar mass is affected by assuming a DM power spectrum with a small-scale cutoff. We compare results obtained by means…
Self-interacting dark matter (SIDM) arises generically in scenarios for physics beyond the Standard Model that have dark sectors with light mediators or strong dynamics. The self-interactions allow energy and momentum transport through…
We present for the first time a suite of cosmological simulations for a particular class of interacting Dark Energy cosmologies characterised by a background expansion history constrained to be indistinguishable from $\Lambda $CDM. Such…
Like early-type galaxies, also nearby galaxy clusters define a Fundamental Plane, a luminosity-radius, and a luminosity-velocity dispersion relations, whose physical origin is still unclear. By means of high resolution N--body simulations…