clustertools.analysis.orbits module

Functions and Operations related to the cluster’s orbit

clustertools.analysis.orbits.initialize_orbit(cluster, from_centre=False, ro=None, vo=None, zo=None, solarmotion=None)

Initialize a galpy orbit instance for the cluster

Parameters:

clusterclass

StarCluster

from_centrebool

intialize orbits from cluster’s exact centre instead of cluster’s position in galaxy (default :False)

rofloat

distance to the Galactic centre (Default: None)

vofloat

circular velocity at ro (Default: None)

zofloat

Sun’s distance above the Galactic plane (default: None)

solarmotionfloat

array representing U,V,W of Sun (default: None)

Returns:

orbitclass

GALPY orbit

clustertools.analysis.orbits.initialize_orbits(cluster, ro=None, vo=None, zo=None, solarmotion=None)

Initialize a galpy orbit for every star in the cluster

Parameters:

clusterclass

StarCluster

rofloat

distance to the Galactic centre (Default: None)

vofloat

circular velocity at ro (Default: None)

zofloat

Sun’s distance above the Galactic plane (default: None)

solarmotionfloat

array representing U,V,W of Sun (default: None)

Returns:

orbitclass

GALPY orbit

clustertools.analysis.orbits.interpolate_orbit(cluster, pot=None, tfinal=None, nt=1000, from_centre=False, ro=None, vo=None, zo=None, solarmotion=None)

Interpolate past or future position of cluster and escaped stars

Parameters:

clusterclass

StarCluster

cluster_potclass

Galpy potential for host cluster that orbit is to be integrated in if None, assume a Plumme Potential

potclass

galpy Potential that orbit is to be integrate in (default: None)

tfinalfloat

final time (in cluster.units) to integrate orbit to (default: 12 Gyr)

ntint

number of timesteps

from_centrebool

intialize orbits from cluster’s exact centre instead of cluster’s position in galaxy (default :False)

rofloat

distance to the Galactic centre (Default: None)

vofloat

circular velocity at ro (Default: None)

zofloat

Sun’s distance above the Galactic plane (default: None)

solarmotionfloat

array representing U,V,W of Sun (default: None)

Returns:

x,y,zfloat

interpolated positions of each star

vx,vy,vzfloat

interpolated velocities of each star

clustertools.analysis.orbits.interpolate_orbits(cluster, pot=None, tfinal=None, nt=1000, ro=None, vo=None, zo=None, solarmotion=None)

Interpolate past or future position of stars within the cluster

Parameters:

clusterclass

StarCluster

potclass

Galpy potential for host cluster that orbit is to be integrated in if None, assume a Plumme Potential

tfinalfloat

final time (in cluster.units) to integrate orbit to (default: 12 Gyr)

ntint

number of timesteps

rofloat

distance to the Galactic centre (Default: None)

vofloat

circular velocity at ro (Default: None)

zofloat

Sun’s distance above the Galactic plane (default: None)

solarmotionfloat

array representing U,V,W of Sun (default: None)

Returns:

x,y,zfloat

interpolated positions of each star

vx,vy,vzfloat

interpolated velocities of each star

clustertools.analysis.orbits.orbit_interpolate(cluster, pot=None, tfinal=None, nt=1000, ro=None, vo=None, zo=None, solarmotion=None)

Interpolate past or future position of cluster and escaped stars

• same as interpolate_orbit, but included for legacy purposes

Parameters:

clusterclass

StarCluster

cluster_potclass

Galpy potential for host cluster that orbit is to be integrated in if None, assume a Plumme Potential

potclass

galpy Potential that orbit is to be integrate in (default: None)

tfinalfloat

final time (in cluster.units) to integrate orbit to (default: 12 Gyr)

ntint

number of timesteps

from_centrebool

intialize orbits from cluster’s exact centre instead of cluster’s position in galaxy (default :False)

rofloat

distance to the Galactic centre (Default: None)

vofloat

circular velocity at ro (Default: None)

zofloat

Sun’s distance above the Galactic plane (default: None)

solarmotionfloat

array representing U,V,W of Sun (default: None)

Returns:

x,y,zfloat

interpolated positions of each star

vx,vy,vzfloat

interpolated velocities of each star

clustertools.analysis.orbits.orbital_path(cluster, tfinal=0.1, nt=1000, pot=None, from_centre=False, skypath=False, initialize=False, ro=None, vo=None, zo=None, solarmotion=None, plot=False, **kwargs)

Calculate the cluster’s orbital path

Parameters:

clusterclass

StarCluster

tfinalfloat

final time (in cluster.units) to integrate orbit to (default: 0.1 Gyr)

ntint

number of timesteps

potclass

galpy Potential that orbit is to be integrate in (default: None)

from_centrebool

genrate orbit from cluster’s exact centre instead of its assigned galactocentric coordinates (default: False)

skypathbool

return sky coordinates instead of cartesian coordinates (default: False)

initializebool

Initialize and return Orbit (default: False)

rofloat

distance to the Galactic centre (Default: None)

vofloat

circular velocity at ro (Default: None)

zofloat

Sun’s distance above the Galactic plane (default: None)

solarmotionfloat

array representing U,V,W of Sun (default: None)

plotbool

plot a snapshot of the cluster in galactocentric coordinates with the orbital path (defualt: False)

Returns:

tfloat

times for which path is provided

x,y,zfloat

orbit positions

vx,vy,vzfloat

orbit velocity

oclass

galpy orbit (if initialize==True)

History

2018 - Written - Webb (UofT)

clustertools.analysis.orbits.orbital_path_match(cluster, tfinal=0.1, nt=1000, pot=None, path=None, from_centre=False, skypath=False, to_path=False, do_full=False, ro=None, vo=None, zo=None, solarmotion=None, plot=False, projected=False, **kwargs)

Match stars to a position along the orbital path of the cluster

Parameters:

clusterclass

StarCluster

tfinalfloat

final time (in cluster.units) to integrate orbit to (default: 0.1 Gyr)

ntint

number of timesteps

potclass

galpy Potential that orbit is to be integrate in (default: None)

patharray

array of (t,x,y,x,vx,vy,vz) corresponding to the tail path. If none path is calculated (default: None)

from_centrebool

genrate orbit from cluster’s exact centre instead of its assigned galactocentric coordinates (default: False)

skypathbool

return sky coordinates instead of cartesian coordinates (default: False) if True, projected is set to True

to_pathbool

measure distance to the path itself instead of distance to central point along the path (default: False)

do_fullbool

calculate dpath all at once in a single numpy array (can be memory intensive) (default:False)

rofloat

distance to the Galactic centre (Default: None)

vofloat

circular velocity at ro (Default: None)

zofloat

Sun’s distance above the Galactic plane (default: None)

solarmotionfloat

array representing U,V,W of Sun (default: None)

plotbool

plot a snapshot of the cluster in galactocentric coordinates with the orbital path (defualt: False)

projectedbool

match to projected orbital path, which means matching just x and y coordinates or Ra and Dec coordinates (not z, or dist) (default:False)

Returns:

tstarfloat

orbital time associated with star

dprogfloat

distance along the orbit to the progenitor

dpath

distance to centre of the orbital path bin (Default) or the orbit path (to_path = True)

clustertools.analysis.orbits.orbits_interpolate(cluster, pot=None, tfinal=None, nt=1000, ro=None, vo=None, zo=None, solarmotion=None)

Interpolate past or future position of stars within the cluster

• same as interpolate_orbits, but kept for legacy purposes

Parameters:

clusterclass

StarCluster

potclass

Galpy potential for host cluster that orbit is to be integrated in if None, assume a Plumme Potential

tfinalfloat

final time (in cluster.units) to integrate orbit to (default: 12 Gyr)

ntint

number of timesteps

rofloat

distance to the Galactic centre (Default: None)

vofloat

circular velocity at ro (Default: None)

zofloat

Sun’s distance above the Galactic plane (default: None)

solarmotionfloat

array representing U,V,W of Sun (default: None)

Returns:

x,y,zfloat

interpolated positions of each star

vx,vy,vzfloat

interpolated velocities of each star