# 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]

NAME:

__init__

PURPOSE:

Initialize a stream spray DF model of a tidal stream

INPUT:

progenitor_mass - mass of the progenitor (can be Quantity)

tdisrupt= (5 Gyr) time since start of disruption (can be Quantity)

leading= (True) if True, model the leading part of the stream
if False, model the trailing part

progenitor= progenitor orbit as Orbit instance (will be re-integrated, so don’t bother integrating the orbit before)

meankvec= (Fardal+2015-ish defaults)

sigkvec= (Fardal+2015-ish defaults)

pot = (None) potential for integrating orbits

rtpot = (pot) 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)

center = (None) 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 = (pot) 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).

OUTPUT:

Instance

HISTORY:

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

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