galpy.df.streamdf.streamTrack

streamdf.streamTrack(custom_sky_transform=None)[source]

Return a StreamTrack wrapping this streamdf’s analytic track, parameterized by perpendicular angle along the stream (tp=0 at the progenitor, tp=_deltaAngleTrack at the far end). The result is cached.

The cov attached to the track is the local (perpendicular-only) covariance, matching streamspraydf.streamTrack()’s convention. Unit metadata is inherited from the progenitor’s Orbit (ro/vo) and from the streamdf’s solar position (zo=Zsun, solarmotion = vsun - [0, vo, 0]), so track.ll/track.bb/track.dist/track.vlos/ track.pmll/track.pmbb reproduce _interpolatedObsTrackLB.

Parameters:

custom_sky_transform (array, shape (3, 3), optional) – One-shot override of self.custom_sky_transform for the cached StreamTrack. Use this when you want the track in a custom (phi1, phi2) sky frame without modifying the streamdf itself. Default None (use the streamdf’s stored transform, if any).

Return type:

galpy.df.StreamTrack

Notes

  • 2026-05-11 - Written - Bovy (UofT)