Related papers: Early Objects in the Cosmic String Theory with Hot…
We use thirty-eight high-resolution simulations of galaxy formation between redshift 10 and 5 to study the impact of a 3 keV warm dark matter (WDM) candidate on the high-redshift Universe. We focus our attention on the stellar mass function…
We present a general description of the scalar field dark matter (SFDM) hypothesis in the cosmological context. The scenario of structure formation under such a hypothesis is based on Jeans instabilities of fluctuations of the scalar field.…
We investigate the creation of cold dark matter (CCDM) cosmology as an alternative to explain the cosmic acceleration. Particular attention is given to the evolution of density perturbations and constraints coming from recent observations.…
We report results from high-resolution particle-mesh (PM) N-body simulations of structure formation in an $\Omega=1$ cosmological model with a mixture of Cold plus Hot Dark Matter (C+HDM) having $\Omega_{\rm cold}=0.6$, $\Omega_\nu=0.3$,…
We investigate the clumping of cold dark matter (CDM) at small scales. If the CDM particle is the neutralino, we find that collisional damping during its kinetic decoupling from the radiation fluid and free streaming introduce a small-scale…
Cosmic string loops lead to nonlinear baryon overdensities at early times, even before the time which in the standard LCDM model corresponds to the time of reionization. These overdense structures lead to signals in 21cm redshift surveys at…
Analytic formulas reproducing the warm dark matter (WDM) primordial spectra are obtained for WDM particles decoupling in and out of thermal equilibrium which provide the initial data for WDM non-linear structure formation. We compute and…
We present an extensive comparison of models of structure formation with observations, based on linear and quasi-linear theory. We assume a critical matter density, and study both cold dark matter models and cold plus hot dark matter…
Many lines of evidence suggest that nonbaryonic dark matter constitutes roughly 30% of the critical closure density, but the composition of this dark matter is unknown. One class of candidates for the dark matter is compact objects formed…
It has been suggested that cosmological dark matter may include a population of vortons (meaning small centrifugally stabilised cosmic string loops) as an outcome of (non-standard) electroweak symmetry breaking. The implications for this…
We examine the structure of baryonic wakes in the cosmological fluid which would form behind GUT-scale cosmic strings at early times (redshifts z > 100) in a neutrino-dominated universe. We show, using simple analytical arguments as well as…
If the dark matter in galactic halos is made up of compact, macroscopic objects (MO), such as black holes with $M_\MO >>M_{stars}$, gravitational scattering will lead to kinematic heating of the stars. Observational constraints on the…
A better understanding of the formation of large-scale structure in the Universe is arguably the most pressing question in cosmology. The most compelling and promising theoretical paradigm, Inflation + Cold Dark Matter, holds that the…
In the standard Cold Dark Matter (CDM) theory of structure formation, virialized minihalos (with T_vir = 10,000 K or less) form in abundance at high redshift (z > 6), during the cosmic "dark ages." The hydrogen in these minihalos, the first…
We study the formation of dark matter halos in the concordance LCDM model over a wide range of redshifts, from z=20 to the present. Our primary focus is the halo mass function, a key probe of cosmology. By performing a large suite of…
Quasars are among the most luminous objects in the universe, and they can be studied in detail up to the highest known redshift. Assuming that the gas associated with quasars is closely related to the interstellar medium of the host galaxy,…
${\rm B - L}$ cosmic strings form in a wide class of theories beyond the Standard Model which contain a ${\rm U}(1)_{{\rm B - L}}$ gauge symmetry. They can form at the end of hybrid inflation and explain, together with inflation, the Cosmic…
The relation between dark matter halos and the loci of star formation at high redshift is a pressing question in contemporary cosmology. Matching the abundance of halos to the abundance of infrared (IR) galaxies, we explicit the link…
The cosmic string scenario in an open universe is developed -- including the equations of motion, a model of network evolution, the large angular scale CMB temperature anisotropy, and the power spectrum of density fluctuations produced by…
We investigate the clustering of high redshift galaxies in five variants of the cold dark matter (CDM) scenario, using hydrodynamic cosmological simulations that resolve the formation of systems with circular velocities $v_c \geq 100 \kms$…