rtidal

clustertools.analysis.functions.rtidal(cluster, pot=None, rtiterate=0, rtconverge=0.9, indx=None, rgc=None, zgc=None, from_centre=False, plot=False, verbose=False, **kwargs)

Calculate tidal radius of the cluster - The calculation uses Galpy (Bovy 2015_, which takes the formalism of Bertin & Varri 2008 to calculate the tidal radius – Bertin, G. & Varri, A.L. 2008, ApJ, 689, 1005 – Bovy J., 2015, ApJS, 216, 29 - riterate = 0 corresponds to a single calculation of the tidal radius based on the cluster’s mass (np.sum(cluster.m)) – Additional iterations take the mass within the previous iteration’s calculation of the tidal radius and calculates the tidal

radius again using the new mass until the change is less than 90%

• for cases where the cluster’s orbital parameters are not set, it is possible to manually set rgc which is assumed to be in kpc.

Parameters:

clusterclass

StarCluster instance

potclass

GALPY potential used to calculate tidal radius (default: None)

rtiterateint

how many times to iterate on the calculation of r_t (default: 0)

rtconvergefloat

criteria for tidal radius convergence within iterations (default 0.9)

indxbool

subset of stars to use when calculate the tidal radius (default: None)

rgcfloat

Manually set galactocentric distance in kpc at which the tidal radius is to be evaluated (default: None)

zgcfloat

For non-spherically symmetric potentials, manually set distance in kpc above disk at which the tidal radius is to be evaluated. When set, rgc becomes radius in cylindrical coordinates (default: None)

rofloat

GALPY radius scaling parameter

vofloat

GALPY velocity scaling parameter

from_centrebool

calculate tidal radius based on location of cluster’s exact centre instead of its assigned galactocentric coordinates (default: False)

plotbool

plot the x and y coordinates of stars and mark the tidal radius of the cluster (default: False)

verbosebool

Print information about iterative calculation of rt

Returns:

rtfloat

tidal radius

Other Parameters:

kwargsstr

key words for plotting