3 Department of Physics, Govt. New Science College, Rewa, (M.P.), 486001, INDIA; __________________________________________________________________________________________ Abstract: Based on SOHO/LASCO catalogue and solar geophysical data, we studied the geoeffectiveness, solar source and flare association of a set of 397 halo CMEs during the period of 1996 to 2008. We find that Disk halos are ...

In this paper we study the angular momentum properties of simulated dark matter halos at high redshift that likely host the first stars in the Universe. Calculating the spin distributions of these 10 − 10 M⊙ halos in redshift slices from z = 15 − 6, we find that they are well fit by a log-normal distribution as is found for lower redshift and more massive halos in earlier work. We find that bot...

We use N-body simulations to study properties of dwarf halos with virial masses in the range 10 − 10hM⊙. Unlike recent reported results, we find that the density profiles of relaxed dwarf halos are well fitted by the NFW profile and do not have cores. We estimate the distribution of concentrations for halos in mass range that covers six orders of magnitude from 10 hM⊙ to 10 13 hM⊙, and find tha...

We study the structure and substructure of halos obtained in N−body simulations for a Λ Cold Dark Matter (ΛCDM) cosmology with non-Gaussian initial conditions (NGICs). The initial statistics are lognormal in the gravitational potential field with positive (LNp) and negative (LNn) skewness; the sign of the skewness is conserved by the density field, and the power spectrum is the same for all the...

We analyze the formation and evolution of stellar bars in galactic disks embedded in mildly triaxial cold dark matter (CDM) halos that have density distributions ranging from large flat cores to cuspy profiles. We have applied tailored numerical simulations of analytical and live halos which include the feedback from disk/bar system onto the halo in order to test and extend earlier work by El-Z...

According to the hierarchical scenario, galaxies form via merging and accretion of small objects. Using N -body simulations, we study the frequency of merging events in the history of the halos. We find that at z ∼< 2 the merging rate of the overall halo population can be described by a simple power law (1+z). The main emphasis of the paper is on the effects of environment of halos at the prese...