title: Critical phenomena in head-on collisions of neutron stars.
abstract: We find type I critical collapses of compact objects modeled by a polytropic equation of state (EOS) with a polytropic index Gamma=2 without the ultrarelativistic assumption. The object is formed in head-on collisions of neutron stars. Further, we show that the critical collapse can occur due to a change of the EOS, without fine-tuning of initial data. This opens the possibility that a neutron-star-like compact object, not just those formed in a collision, may undergo a critical collapse in processes which slowly change the EOS, such as cooling.
authors.affiliation: McDonnell Center for the Space Sciences, Department of Physics, Washington University, St. Louis, MO 63130, USA.
authors.forename: Ke-Jian
authors.initials: KJ
authors.lastname: Jin
authors.forename: Wai-Mo
authors.initials: WM
authors.lastname: Suen