# FardalStreamDF¶

class gala.dynamics.FardalStreamDF

A class for representing the Fardal+2015 distribution function for generating stellar streams based on Fardal et al. 2015

Parameters

Generate a leading tail. Default: True.

trailbool (optional)

Generate a trailing tail. Default: True.

random_stateRandomState (optional)

To control random number generation.

Attributes Summary

 lead random_state random_state: object trail

Methods Summary

 sample(self, prog_orbit, prog_mass[, …]) Generate stream particle initial conditions and initial times.

Attributes Documentation

lead
random_state

random_state: object

trail

Methods Documentation

sample(self, prog_orbit, prog_mass, hamiltonian=None, release_every=1, n_particles=1) sample(prog_orbit, prog_mass, hamiltonian=None, release_every=1, n_particles=1)

Generate stream particle initial conditions and initial times.

This method is primarily meant to be used within the MockStreamGenerator.

Parameters
prog_orbitOrbit

The orbit of the progenitor system.

prog_massQuantity [mass]

The mass of the progenitor system, either a scalar quantity, or as an array with the same shape as the number of timesteps in the orbit to account for mass evolution.

hamiltonianHamiltonian

The external potential and reference frame to numerically integrate orbits in.

release_everyint (optional)

Controls how often to release stream particles from each tail. Default: 1, meaning release particles at each timestep.

n_particlesint, array_like (optional)

If an integer, this controls the number of particles to release in each tail at each release timestep. Alternatively, you can pass in an array with the same shape as the number of timesteps to release bursts of particles at certain times (e.g., pericenter).

Returns
xyzQuantity [length]

The initial positions for stream star particles.

v_xyzQuantity [speed]

The initial velocities for stream star particles.

t1Quantity [time]

The initial times (i.e. times to start integrating from) for stream star particles.