相关论文: Can Photoionization Squelching Resolve the Sub-str…
Recent observations on the cosmic microwave background by Wilkinson Microwave Anisotropy Probe(WMAP) strongly suggest that the reionization of the universe took place quite early (z \sim 17). On the other hand, it has been pointed out that…
Warm dark matter cosmologies have been widely studied as an alternative to the cold dark matter paradigm, the characteristic feature being a suppression of structure formation on small cosmological scales. A very similar situation occurs if…
It has been argued that a UV photoionizing background radiation field suppresses the formation of dwarf galaxies, and may even inhibit the formation of larger galaxies. In order to test this, we present gas-dynamical simulations of the…
Self-interacting dark matter has been proposed as a solution to the small-scale structure problems, such as the observed flat cores in dwarf and low surface brightness galaxies. If scattering takes place through light mediators, the…
One of the main challenges facing standard hierarchical structure formation models is that the predicted abundance of galactic subhalos with circular velocities of 10-30 km/s is an order of magnitude higher than the number of satellites…
We have developed a new semi-analytic model for the formation and evolution of structure on galaxy, group and cluster scales. The model combines merger trees with a detailed, spatially resolved description of the dynamical evolution of halo…
We present results for a galaxy formation model that includes a simple treatment for the disruption of dwarf galaxies by gravitational forces and galaxy encounters within galaxy clusters. This is implemented a posteriori in a semi-analytic…
We investigate the effects of the observed UV background radiation on galaxy formation. Photoionization by UV radiation decreases the cooling rate of the gas in halos, so that objects with only large density contrasts can self-shield…
Current models of galaxy formation lack an efficient and physically constrained mechanism to regulate star formation (SF) in low and intermediate mass galaxies. We argue that the missing ingredient could be the effect of photoionization by…
Sterile neutrino dark matter is expected to suppress structure formation at small astrophysical scales. The details of the suppression depend on the sterile neutrino production mechanism in the early universe. In this proceeding, we focus…
The cold dark matter (CDM) cosmological model has been remarkably successful in explaining cosmic structure over an enormous span of redshift, but it has faced persistent challenges from observations that probe the innermost regions of dark…
We reanalyze the photoevaporation problem of subgalactic objects irradiated by UVB radiation in a reionized universe. For the purpose, we perform three-dimensional radiation smoothed-particle-hydrodynamics calculations, where the radiative…
Cold Dark Matter (CDM) models of galaxy formation had been remarkably successful to explain a number of observations in the past decade. However, with both the theoretical modeling and the observations being improved, CDM models have been…
In this paper we investigate the overcooling problem and propose some possible solutions. We show that the overcooling problem is generic to the hierarchical picture of structure formation, as long as the cooling is actually possible in…
We use a self-consistent model of galaxy formation and the evolution of the intergalactic medium to study the effects of the reionization of the universe at high redshift on the properties of satellite galaxies like those seen around the…
We use a cosmological simulation of the formation of the Local Group of Galaxies to identify a mechanism that enables the removal of baryons from low-mass halos without appealing to feedback or reionization. As the Local Group forms, matter…
The Lambda Cold Dark Matter (LCDM) paradigm makes specific predictions for the abundance, structure, substructure and clustering of dark matter halos, the sites of galaxy formation. These predictions can be directly tested, in the low-mass…
A possible explanation of the present discrepancy between the abundance of galactic subhaloes predicted by N-Body simulations with those observed in the Local Group is presented. We study the impact of an early reionization on the baryonic…
The Local Group contains some dwarf galaxies that apparently formed all their stars early, lost their gas to winds or ionization, and survive today as ``fossils'' from the epoch of reionization. This study presents new models of these…
Observations on galactic scales seem to be in contradiction with recent high resolution N-body simulations. This so-called cold dark matter (CDM) crisis has been addressed in several ways, ranging from a change in fundamental physics by…