"Star Formation in Dwarf Galaxies"

 

 

 

I will present results from a fully cosmological, extremely high-resolution LCDM simulation of a cosmological sheet of dwarf galaxies, utilizing the new N-body + SPH code ChaNGa.  The present day virial masses of these dwarfs range from Mvir=3.3x109 – 1.3x1010 for halos which form stars.  The simulation includes a blastwave scheme for supernova feedback, a novel scheme for implementing early stellar feedback, metal-dependent radiative cooling, a scheme for the turbulent diffusion of metals and thermal energy, as well as a uniform UV background.  The dwarfs show excellent agreement with the present-day Stellar to Halo Mass (SMHM) relationship, have realistic blue colors and low star formation rates in addition to realistic baryon fractions, colors and metallicities.  Their cumulative star formation histories show excellent agreement with local group dwarfs, especially when observational corrections are applied.  I will show the affects of baryon physics on virial mass: specifically, we verify that the change in halo mass between a baryonic and dark matter only run, for galaxies with halo masses greater than 10^{^10} solar masses, can be explained entirely by a change in virial radius.  This change results from a different over density resulting from baryon loss. In halos smaller than this, the smaller virial radius in the SPH run cannot completely account for the change in halo mass, and it appears that the lowered mass of these halos also leads to lower accretion into these small halos.