A Mechanism for the Present-Day Creation of a New Class of Black Holes
  In this first paper of a series on the formation and abundance of substellar mass dwarf black holes (DBHs), we present a heuristic for deducing the stability of non-rotating matter embedded in a medium against collapse and the formation of a black hole. We demonstrate the heuristic's accuracy for a family of spherical mass distributions whose stability is known through other means. We also present the applications of this heuristic that could be applied to data sets of various types of simulations, including the possible formation of DBHs in the expanding gases of extreme astrophysical phenomena including Type Ia and Type II supernovae, hypernovae, and in the collision of two compact objects. These papers will also explore the observational and cosmological implications of DBHs, including estimates of the total masses of these objects bound in galaxies and ejected into the intergalactic medium. Applying our formalism to a Type II supernova simulation, we have found regions in one data set that are within a factor of three to four of both the density and mass necessary to create a DBH. 
Andrew P. Hayes and Neil F. Comins
astro-ph.HE