Resolving Subhaloes' Lives with the Hierarchical Bound-Tracing Algorithm
  We develop a new code, the Hierarchical Bound-Tracing (HBT for short) code,
to find and trace dark matter subhaloes in simulations based on the merger
hierarchy of dark matter haloes. Application of this code to a recent benchmark
test of finding subhaloes demonstrates that HBT stands as one of the best codes
to trace the evolutionary history of subhaloes. The success of the code lies in
its careful treatment of the complex physical processes associated with the
evolution of subhaloes and in its robust unbinding algorithm with an adaptive
source subhalo management. We keep a full record of the merger hierarchy of
haloes and subhaloes, and allow growth of satellite subhaloes through accretion
from its "satellite-of-satellites", hence allowing mergers among satellites.
Local accretion of background mass is omitted, while rebinding of stripped mass
is allowed. The justification of these treatments is provided by case studies
of the lives of individual subhaloes and by the success in finding the complete
subhalo catalogue. We compare our result to other popular subhalo finders and
show that HBT is able to well resolve subhaloes in high density environment and
keep strict physical track of subhaloes' merger history. This code is fully
parallelized and freely available upon request to the authors.
