A library of hybrid N-body + test particle simulations for dynamical modeling of galaxy interactions.
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Idk12X
Idk12Xrun
Idk13X
Idk13Xrun
Idk19X
Idk19Xrun
README.md
bulge_g1_a0078_b4_e00375.txt
bulge_g1_a02_b4_e00375.txt
halo_c039_a0884_e00375.txt
halo_c039_a25_e00375.txt

README.md

Identikit Models

A library of hybrid N-body + test particle simulations for dynamical modeling of galaxy interactions. These are intended for use within the Identikit environment.

This repository consists of bulge+disk+NFW halo galaxy models to facilitate exploration of encounters with various mass ratios. The "full mass" and "half mass" models are the same as those provided by Barnes & Hibbard (2009) and the makefiles are essentially identical to those provided with Identikit, but separated into different files.

The "quarter mass" and "eighth mass" models have been created by George Privon. These models were computed by further reducing the scale lengths by a factor sqrt(2) for each halving of the mass.

The initial conditions files given below provide sample encounters for parabolic orbits and a variety of pericenter seperations.

Software Requirements

Constructing the initial conditions and running these simulations requires installation of the Zeno N-body/SPH simulation environment (github link).

Files

Initial Conditions and Run Files

The initial conditions files and run files follow a naming convention of IdkZYX and IdkZYXrun, where the numbers replacing ZYX correspond to:

  • Z = 1 indicating parabolic orbits.
  • Y indicating the sum of the fractional masses of the interacting galaxies. 2 indicates an equal-mass encounter (1+1) while 5 indicates a 1:4 mass ratio (1+4).
  • X indicates the pericenter separation at first pass, for the idealized Keplerian orbit. This corresponds to multiples of 1/16 simulation units.

Thus, Idk12X contains initial conditions for equal mass galaxy encounters on parabolic orbits. The file has a range of first pericenter encounters (1/16 through 16/16, in simulation units). The Idk12Xrun file contains routines to evolve the initial conditions for a suitable time range and save the snapshots for comparison with data.

Support Files

Citations

Users of these models should cite Barnes & Hibbard (2009).