The particle-spray stream DF

class galpy.df.streamspraydf(progenitor_mass, progenitor=None, pot=None, rtpot=None, tdisrupt=None, leading=True, center=None, centerpot=None, meankvec=[2.0, 0.0, 0.3, 0.0, 0.0, 0.0], sigkvec=[0.4, 0.0, 0.4, 0.5, 0.5, 0.0], ro=None, vo=None)[source]
__init__(progenitor_mass, progenitor=None, pot=None, rtpot=None, tdisrupt=None, leading=True, center=None, centerpot=None, meankvec=[2.0, 0.0, 0.3, 0.0, 0.0, 0.0], sigkvec=[0.4, 0.0, 0.4, 0.5, 0.5, 0.0], ro=None, vo=None)[source]

Initialize a stream spray DF model of a tidal stream

Parameters:

  • progenitor_mass (float or Quantity) – Mass of the progenitor.

  • progenitor (galpy.orbit.Orbit, optional) – Progenitor orbit as Orbit instance (will be re-integrated, so don’t bother integrating the orbit before).

  • pot (galpy.potential.Potential or list of such instances, optional) – Potential for integrating orbits.

  • rtpot (galpy.potential.Potential or list of such instances, optional) – Potential for calculating tidal radius and circular velocity (should generally be the same as pot, but sometimes you need to drop parts of the potential that don’t allow the tidal radius / circular velocity to be computed, such as velocity-dependent forces; when using center, rtpot should be the relevant potential in the frame of the center, thus, also being different from pot).

  • tdisrupt (float or Quantity, optional) – Time since start of disruption. Default is 5 Gyr.

  • leading (bool, optional) – If True, model the leading part of the stream. If False, model the trailing part. Default is True.

  • center (galpy.orbit.Orbit, optional) – Orbit instance that represents the center around which the progenitor is orbiting for the purpose of stream formation; allows for a stream to be generated from a progenitor orbiting a moving object, like a satellite galaxy. Integrated internally using centerpot.

  • centerpot (galpy.potential.Potential or list of such instances, optional) – Potential for calculating the orbit of the center; this might be different from the potential that the progenitor is integrated in if, for example, dynamical friction is important for the orbit of the center (if it’s a satellite).

  • meankvec (list or array, optional) – Mean of the action-angle distribution. Default is [2.0, 0.0, 0.3, 0.0, 0.0, 0.0].

  • sigkvec (list or array, optional) – Dispersion of the action-angle distribution. Default is [0.4, 0.0, 0.4, 0.5, 0.5, 0.0].

  • ro (float or Quantity, optional) – Distance scale for translation into internal units (default from configuration file).

  • vo (float or Quantity, optional) – Velocity scale for translation into internal units (default from configuration file).

Notes

  • 2018-07-31 - Written - Bovy (UofT)

  • 2021-05-05 - Added center keyword - Yansong Qian (UofT)