SHEAR FIELDS AND THE EVOLUTION OF GALACTIC SCALE DENSITY PEAKS

We present preliminary results of our investigation into the influence of shear fields on the evolution of galactic scale fluctuations in a primordial Gaussian random density field. Specifically, we study how the matter associated with a galaxy scale peak evolves, to determine whether the shear can affect the peak's ability to form a virialized structure. We find that the evolution of the mass distribution in the immediate surroundings of greater than or equal to 1 sigma initial density peaks is sensitive to the nature and magnitude of the shear. Its final fate and configuration spans a plethora of possibilities, ranging from accretion onto the peak to complete disruption. On the other hand, the mass defining the peak itself tends to form a virialized object, though a given galaxy scale peak need not necessarily form only one halo. Furthermore, galaxy-sized halos need not necessarily be associated with initial galaxy scale density peaks. Under certain conditions, the shear field is capable of breaking up a single primordial peak into two (and perhaps, more) distinct halos, or of promoting the growth of smaller scale peaks into galaxy-sized halos.