Related papers: What does the Bullet Cluster tell us about self-in…
We present new weak lensing observations of 1E0657-558 (z=0.296), a unique cluster merger, that enable a direct detection of dark matter, independent of assumptions regarding the nature of the gravitational force law. Due to the collision…
If dark matter interacts with nuclei or electrons, then elastic collisions with constituents of stars will cause some of the galactic dark matter to fall below the escape velocity and become gravitationally bound. For asymmetric dark matter…
Self-interactions facilitate inter-particle redistribution of energy within the dense regions of galactic halos, implying modifications in the density and velocity distribution of dark matter. Simulating dark-matter only isolated halos for…
Simulations of self-interacting dark matter (SIDM) predict that dark matter should lag behind galaxies during a collision. If the interaction is mediated by a high-mass force carrier, the distribution of dark matter can also develop…
It is plausible that the dark matter particles have non-gravitational interactions among themselves. If such self interactions are large enough, they could leave an imprint on the morphology of galaxies. These effects can be studied with…
We use a combination of N-body simulations of the hierarchical clustering of dark matter and semi-analytic modelling of the physics of galaxy formation to probe the relationship between the galaxy distribution and the mass distribution. The…
We use the Cluster-EAGLE simulations to explore the velocity bias introduced when using galaxies, rather than dark matter particles, to estimate the velocity dispersion of a galaxy cluster, a property known to be tightly correlated with…
We present DLSCL J0916.2+2951 (z=0.53), a newly discovered major cluster merger in which the collisional cluster gas has become dissociated from the collisionless galaxies and dark matter. We identified the cluster using optical and weak…
The internal dynamics of a dark matter structure may have the remarkable property that the local temperature in the structure depends on direction. This is parametrized by the velocity anisotropy beta which must be zero for relaxed…
We present cosmological simulations of galaxy clusters, with focus on the cluster outskirts. We show that large-scale cosmic accretion and mergers produce significant internal gas motions and inhomogeneous gas distribution ("clumpiness") in…
We use a large set N-body/hydrodynamical simulations to study the physical properties of the merging cluster El Gordo. We find that the observed X-ray structures, along with other data, can be matched fairly well by simulations with…
We investigate an analytic model to compute nonlinear power spectrum of dark matter, galaxies and their cross-correlation. The model is based on Press-Schechter halos, which cluster and have realistic dark matter profiles. The total power…
Evidence for dark matter self-interactions has recently been reported based on the observation of a spatial offset between the dark matter halo and the stars in a galaxy in the cluster Abell 3827. Interpreting the offset as due to dark…
Low energy interactions between particles are often characterised by elastic scattering. Just as electrons undergo Thomson scattering with photons, dark matter particles may experience an analogous form of momentum exchange with dark…
Dark matter with a non-zero self-interacting cross section ($\sigma_{\rm SIDM}$) has been posited as a solution to a number of outstanding astrophysical mysteries. Many studies of merging galaxy clusters have given constraints on…
Dark matter (DM) self-interactions have important implications for the formation and evolution of structure, from dwarf galaxies to clusters of galaxies. We study the dynamics of self-interacting DM via a light mediator, focusing on the…
We suggest that the dark matter model based on Bose Einstein condensate or scalar field can resolve the apparently contradictory behaviors of dark matter in the Abell 520 and the Bullet cluster. During a collision of two galaxies in the…
We consider a self-interacting dark matter model in which the massive dark photon mediating the self-interaction decays to light dark fermions to avoid over-closing the universe. We find that if the model is constrained to explain the dark…
We use semi-analytic modeling on top of the Millennium simulation to study the joint formation of galaxies and their embedded supermassive black holes. Our goal is to test scenarios in which black hole accretion and quasar activity are…
Cosmological models with cold dark matter composed of weakly interacting particles predict overly dense cores in the centers of galaxies and clusters and an overly large number of halos within the Local Group compared to actual…