Fragmentation and Core Formation in Dynamically Collapsing Rotating Clouds

Abstract

Cold Dark Matter (CDM) models for structure formation predict the appearance of the first baryonic objects with masses M ~ 1O⁵ M _⊙ at redshifts as high z~ 30; objects with progressively higher masses assemble later¹. Depending on the details of the cooling and angular momentum transport, these objects are expected to either fragment into smaller objects, or form central black holes exhibiting quasar activity². Cosmological simulations with large amount of volume have revealed potential sites in which the first object probably forms³. The subsequent evolution of these collapsing objects is, however, still in open question. To understand the subsequent evolution, we have to clarify how and when these objects collapse and fragment. In this work, we focus on the three-dimensional hydrodynamical evolution of a single density peak, taking into account the H₂ chemistry.