相关论文: Axion Miniclusters Made Easy

We compute the real-space cluster-galaxy cross-correlation xi_cg(r) using the ROSAT-ESO Flux Limited X-ray (REFLEX) cluster survey, a group catalogue constructed from the final version of the 2dFGRS, and galaxies extracted from 2MASS and…

The explosive percolation problem on the complete graph is investigated via extensive numerical simulations. We obtain the cluster-size distribution at the moment when the cluster size heterogeneity becomes maximum. The distribution is…

Ultracompact dark matter (DM) minihalos at masses at and below $10^{-12}$ $M_\odot$ arise in axion DM models where the Peccei-Quinn (PQ) symmetry is broken after inflation. The minihalos arise from density perturbations that are generated…

We present multi-wavelength studies of optically-defined merging clusters, based on the Hyper Suprime-Cam Subaru Strategic Program. Luminous red galaxies, tracing cluster mass distributions, enable to identify cluster subhalos at various…

We construct an analytical model of the mass distribution function of subhalos in a galaxy cluster in the context of the cold dark matter (CDM) theory. Our model takes account of two important effects; the high density of the precluster…

Using hydrodynamical simulations, we study how well the underlying gravitational potential of a galaxy cluster can be modelled dynamically with different types of tracers. In order to segregate different systematics and the effects of…

We analyze the halo occupation distribution (HOD), the probability for a halo of mass M to host a number of subhalos N, and two-point correlation function of galaxy-size dark matter halos using high-resolution dissipationless simulations of…

The abundance of dark matter haloes is one of the key probes of the growth of structure and expansion history of the Universe. Theoretical predictions for this quantity usually assume that, when expressed in a certain form, it depends only…

We develop a simple analytic model for the gravitational clustering of dark haloes. The statistical properties of dark haloes are determined from the initial density field (assumed to be Gaussian) through an extension of the Press-Schechter…

In the ellipsoidal collapse model, the critical density for the collapse of a gravitationally bound object is a function of its mass. In the excursion set formalism, this translates into a moving barrier problem such that the mass function…

We compute the quantum tunneling rate of dilute axion stars close to the maximum mass [P.H. Chavanis, Phys. Rev. D {\bf 84}, 043531 (2011)] using the theory of instantons. We confirm that the lifetime of metastable states is extremely long,…

The peculiar velocity field measured by redshift-space distortions (RSD) in galaxy surveys provides a unique probe of the growth of large-scale structure. However, systematic effects arise when including satellite galaxies in the clustering…

Axions are a viable candidate for Cold Dark Matter (CDM) which should generically form minihalos of sub-planetary masses from white-noise isocurvature density fluctuations if the Peccei-Quinn phase transition occurs after inflation. Despite…

Velocity dispersions have been employed as a method to measure masses of clusters. To complement this conventional method, we explore the possibility of constraining cluster masses from the stacked phase space distribution of galaxies at…

We use cosmological gas dynamic simulations to investigate the accuracy of galaxy cluster mass estimates based on X-ray observations. The experiments follow the formation of clusters in different cosmological models and include the effects…

The mass function of galaxies and clusters of galaxies can be derived observationally based on different types of observations. In this study we test if these observations can be combined to a consistent picture which is also in accord with…

A sizeable level of non-Gaussianity in the primordial cosmological perturbations may be induced by a large trispectrum, i.e. by a large connected four-point correlation function. We compute the effect of a primordial non-Gaussian…

Axion physics is briefly reviewed. Constraints from laboratory searches, astrophysics and cosmology require the axion mass to be in the range $10^{-6} \lesssim m_a < 3\cdot 10^{-3}$eV. Near the lower end of this range, axions are all or a…

A method of deriving and using merging history trees of dark matter galaxy haloes directly from pure gravity N-body simulations is presented. This combines the full non-linearity of N-body simulations with the flexibility of the…

Laboratory experiments have the capacity to detect the QCD axion in the next decade, and precisely measure its mass, if it composes the majority of the dark matter. In type IIB string theory on Calabi-Yau threefolds in the geometric regime,…