holodeck API Reference
holodeck: Massive Black-Hole Binary Population Synthesis & Gravitational Wave Calculations ≋●≋●≋
This package is aimed at providing a comprehensive framework for MBH binary population synthesis. The framework includes modules to perform pop synth using a variety of methodologies to get a handle on both statistical and systematic uncertainties. Currently, binary populations can be synthesis based on: cosmological hydrodynamic simulations (Illustris), semi-analytic/semi-empirical models, and observational catalogs of local galaxies and/or quasars.
See the README.md file for more information. The github repository is: https://github.com/nanograv/holodeck. Additional documentation can be found at: holodeck-gw.readthedocs.io/en/docs/index.html. Note that the readthedocs documentation can also be built locally from the holodeck/docs folder. A methods paper for holodeck is currently in preparation.
In general, holodeck calculations proceed in three stages:
Population: Construct an initial population of MBH ‘binaries’. This is typically done for pairs of MBHs when their galaxies merge (i.e. long before the two MBHs are actually a gravitationally-bound binary). Constructing the initial binary population may occur in a single step: e.g. gathering MBH-MBH encounters from cosmological hydrodynamic simulations; or it may occur over two steps: (i) gathering galaxy-galaxy encounters, and (ii) prescribing MBH properties for each galaxy.
Evolution: Evolve the binary population from their initial conditions (i.e. large separations) until coalescence (i.e. small separations). The complexity of this evolutionary stage can range tremendously in complexity. In the simplest models, binaries are assumed to coalesce instantaneously (in that the age of the universe is the same at formation and coalescence), and are assumed to evolve purely due to GW emission (in that the time spent in any range of orbital frequencies can be calculated from the GW hardening timescale). Note that these two assumptions are contradictory.
Gravitational Waves: Calculate the resulting GW signals based on the binaries and their evolution. Note that GWs can only be calculated based on some sort of model for binary evolution. The model may be extremely simple, in which case it is sometimes glanced over.