Rapidly rotating Δ-resonance-admixed hypernuclear compact stars
Jia Jie Li (Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China, School of Physical Science and Technology, Southwest University, Chongqing, China, Institute for Theoretical Physics, J. W. Goethe University, Frankfurt am Main, Germany)
; Armen Sedrakian (Institute of Theoretical Physics, University of Wroclaw, Wroclaw, Poland, Frankfurt Institute for Advanced Studies, Frankfurt am Main, Germany)
; Fridolin Weber (Department of Physics, San Diego State University, San Diego, USA, Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla, USA)
We use a set of hadronic equations of state derived from covariant density functional theory to study the impact of their high-density behavior on the properties of rapidly rotating Δ-resonance-admixed hyperonic compact stars. In particular, we explore systematically the effects of variations of the bulk energy isoscalar skewness, , and the symmetry energy slope, , on the masses of rapidly rotating compact stars. With models for equation of state satisfying all the modern astrophysical constraints, excessively large gravitational masses of around are only obtained under three conditions: (a) strongly attractive Δ-resonance potential in nuclear matter, (b) maximally fast (Keplerian) rotation, and (c) parameter ranges MeV and MeV. These values of and have a rather small overlap with a large sample (total of about 260) parametrizations of covariant nucleonic density functionals. The extreme nature of requirements (a)-(c) reinforces the theoretical expectation that the secondary object involved in the GW190814 event is likely to be a low-mass black hole rather than a supramassive neutron star.