Dominik2

Previous calculations suggest star-forming environments very unlike our own (“low metallicity”) formed very massive binary black holes exceptionally frequently. Because short GRBs and gravitational waves are detectable over vast distances, a careful prediction for mergers over cosmic time must include this trend.

We created a few plausible synthetic universes and populated them with merging binaries, accounting for when and where each was born; how long each binary lasts; and time-dependent star forming conditions. Because the rate at which stars form decreases and the composition of the universe gradually changes as stars produce more heavy elements, the intrinsic merger rate per unit volume increases rapidly with redshift out to the era of peak star formation (Domink et al 2013). In other words, rare ancient star formation matters.

For experts: The eight fiducial synthetic universes constructed here are used later to predict compact binary detection rates.
Our calculations should also be useful when interpreting compact binary merger populations over cosmic time, including reconciling short GRB event rates and redshift distributions with galactic and (soon) LIGO constraints.

For more information, see

• Our current paper Domink et al 2013 ApJ 779 72.

• Our prior work: Dominik et al 2012 ApJ 759 52