Massive double compact object mergers: gravitational wave sources and r-process-element production sites

Understand

With our galactic evolutionary code that contains a detailed intermediate mass and massive binary population model, we study the temporal evolution of the galactic population of double neutron star binaries, mixed systems with a neutron star and black hole component and double black hole binaries.

• We compute the merger rates of these relativistic binaries and we translate them into LIGO II detection rates.
• We demonstrate that accounting for the uncertainties in the relation 'initial mass-final mass' predicted by massive close binary evolution and due to the possible effect of large stellar wind mass loss during the luminous blue variable phase of a star with initial mass larger than 30-40 Mo and during the red supergiant phase of a star with initial mass smaller than 30-40 Mo when such a star is a binary component, the double black hole merger rate may be very small, contrary to predictions made by other groups.
• Hydrodynamic computations of r-process chemical yields ejected during the relativistic binary merger process have recently become available.