The observation of a compact object with a mass of $2.50-2.67M_{\odot}$ on August 14, 2019, by the LIGO Scientific and Virgo collaborations (LVC) has the potential to improve our understanding of the supranuclear equation of state. While the gravitational-wave analysis of the LVC suggests that GW190814 likely was a binary black hole system, the secondary component could also have been the heaviest neutron star observed to date. We use our previously derived nuclear-physics-multimessenger astrophysics framework to address the nature of this object. Based on our findings, we determine GW190814 to be a binary black hole merger with a probability of $>99.9\%$. Even if we weaken previously employed constraints on the maximum mass of neutron stars, the probability of a binary black hole origin is still $\sim 81\%$. Furthermore, we study the impact that this observation has on our understanding of the nuclear equation of state by analyzing the allowed region in the mass-radius diagram of neutron stars for both a binary black hole or neutron star--black hole scenario. We find that the unlikely scenario in which the secondary object was a neutron star requires rather stiff equations of state with a maximum speed of sound $c_s\geq \sqrt{0.6}$ times the speed of light, while the binary black hole scenario does not offer any new insight.
Unraveling information about supranuclear-dense matter from the complete binary neutron star coalescence process using future gravitational-wave detector networks
Polar Mounds on Strangeon Stars: the Neutrino Emission from Ultraluminous X-ray Pulsars
Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学科维理天文与天体物理研究所）；School of Astronomy and Space Science, Nanjing University（南京大学天文与空间科学学院）；Key Laboratory of Modern Astronomy and Astrophysics, Nanjing University, Ministry of Education（南京大学现代天文与天体物理教育部重点实验室）；Department of Astronomy, School of Physics, Peking University（北京大学物理学院天文学系）
Using Equation of State Constraints to Classify Low-Mass Compact Binary Mergers
California Institute of Technology（加州理工学院）；LIGO Laboratory, California Institute of Technology（激光干涉引力波天文台，加州理工学院）；Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理学研究所（爱因斯坦研究所））
Simulating Binary Neutron Stars with Hybrid Equation of States: Gravitational Waves, Electromagnetic Signatures, and Challenges for Numerical Relativity
