The delayed time distribution of massive double compact star mergers

TL;DR

This paper presents the delayed time distribution (DTD) for merging double neutron star binaries and neutron star-black hole systems, enabling better modeling of their impact on galactic chemical evolution without explicitly simulating binaries.

Contribution

It provides the first detailed DTDs for these mergers, facilitating their inclusion in galactic evolution models that lack explicit binary treatment.

Findings

DTD for double neutron star mergers characterized

DTD for neutron star-black hole mergers characterized

Implications for r-process element production analyzed

Abstract

In order to investigate the temporal evolution of binary populations in general, double compact star binaries and mergers in particular within a galactic evolution context, a most straightforward method is obviously the implementation of a detailed binary evolutionary model in a galactic chemical evolution code. To our knowledge, the Brussels galactic chemical evolution code is the only one that fully consistently accounts for the important effects of interacting binaries on the predictions of chemical evolution. With a galactic code that does not explicitly include binaries, the temporal evolution of the population of double compact star binaries and mergers can be estimated with reasonable accuracy if the delayed time distribution (DTD) for these mergers is available. The DTD for supernovae type Ia has been studied extensively the last decade. In the present paper we present the DTD for merging double neutron star binaries and mixed systems consisting of a neutron star and a black hole. The latter mergers are very promising sites for the production of r-process elements and the DTDs can be used to study the galactic evolution of these elements with a code that does not explicitly account for binaries.