Coalescing binary systems of compact objects: Dynamics of angular momenta

TL;DR

This paper investigates how the angular momentum and mass of coalescing binary compact objects influence their final state, considering gravitational radiation, spin effects, and the conditions for black hole or neutron star formation.

Contribution

It provides an analysis of the evolution of angular momentum to mass ratio during inspiral, including spin effects and precession, affecting the final outcome of the binary system.

Findings

Some systems do not meet conditions for black hole or neutron star formation after inspiral.

Spin effects and precession are significant for gravitational waveform calculations.

The ratio J/M^2 can exceed thresholds for black hole or neutron star formation.

Abstract

The end state of a coalescing binary of compact objects depends strongly on the final total mass M and angular momentum J. Since gravitational radiation emission causes a slow evolution of the binary system through quasi-circular orbits down to the innermost stable one, in this paper we examine the corresponding behavior of the ratio J/M^2 which must be less than 1(G/c) or about 0.7(G/c) for the formation of a black hole or a neutron star respectively. The results show cases for which, at the end of the inspiral phase, the conditions for black hole or neutron star formation are not satisfied. The inclusion of spin effects leads us to a study of precession equations valid also for the calculation of gravitational waveforms.