# LagrangeCloudStreamDF¶

class gala.dynamics.LagrangeCloudStreamDF(v_disp, lead=True, trail=True, random_state=None)

A class for representing the Lagrange Cloud Stripping distribution function for generating stellar streams. This df is based on Gibbons et al. 2014 but has since been modified by, e.g., Erkal et al. 2019.

Parameters
v_dispQuantity [speed]

The velocity dispersion of the released particles.

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 v_disp v_disp: object

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
v_disp

v_disp: object

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.