TY - INPR A1 - Ecker, Christian A1 - Topolski, Konrad A1 - Järvinen, Matti A1 - Stehr, Alina T1 - Prompt black hole formation in binary neutron star mergers T2 - arXiv N2 - We carry out an in-depth analysis of the prompt-collapse behaviour of binary neutron star (BNS) mergers. To this end, we perform more than 80 general relativistic BNS merger simulations using a family of realistic Equations of State (EOS) with different stiffness, which feature a first order deconfinement phase transition between hadronic and quark matter. From these simulations we infer the critical binary mass Mcrit that separates the prompt from the non-prompt collapse regime. We show that the critical mass increases with the stiffness of the EOS and obeys a tight quasi-universal relation, Mcrit/MTOV ≈ 1.41 ± 0.06, which links it to the maximum mass MTOV of static neutron stars, and therefore provides a straightforward estimate for the total binary mass beyond which prompt collapse becomes inevitable. In addition, we introduce a novel gauge independent definition for a one-parameter family of threshold masses in terms of curvature invariants of the Riemann tensor which characterizes the development toward a more rapid collapse with increasing binary mass. Using these diagnostics, we find that the amount of matter remaining outside the black hole sharply drops in supercritical mass mergers compared to subcritical ones and is further reduced in mergers where the black hole collapse is induced by the formation of a quark matter core. This implies that Mcrit, particularly for merger remnants featuring quark matter cores, imposes a strict upper limit on the emission of any detectable electromagnetic counterpart in BNS mergers. KW - neutron stars KW - equation of state KW - binary neutron star mergers KW - black holes Y1 - 2024 UR - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/83879 UR - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-838796 UR - https://arxiv.org/abs/2402.11013v1 IS - 2402.11013v1 PB - arXiv ER -