Rotate-and-tilt wrapper potential

class galpy.potential.RotateAndTiltWrapperPotential(amp=1.0, inclination=None, galaxy_pa=None, sky_pa=None, zvec=None, offset=None, pot=None, ro=None, vo=None)[source]

Potential wrapper that allows a potential to be rotated in 3D according to three orientation angles. These angles can either be specified using:

  • A rotation around the original z-axis (galaxy_pa) and the new direction of the z-axis (zvec) or

  • A rotation around the original z-axis (galaxy_pa), the inclination, and a rotation around the new z axis (sky_pa).

The second option allows one to specify the inclination and sky position angle (measured from North) in the usual manner in extragalactic observations. A final offset option allows one to apply a static offset in Cartesian coordinate space to be applied to the potential following the rotation and tilt.

__init__(amp=1.0, inclination=None, galaxy_pa=None, sky_pa=None, zvec=None, offset=None, pot=None, ro=None, vo=None)[source]

A potential that rotates and tilts another potential.

Parameters:

  • amp (float, optional) – Overall amplitude to apply to the potential. Default is 1.0.

  • inclination (float or Quantity, optional) – Usual inclination angle (with the line-of-sight being the z axis).

  • galaxy_pa (float or Quantity, optional) – Rotation angle of the original potential around the original z axis.

  • sky_pa (float or Quantity, optional) – Rotation angle around the inclined z axis (usual sky position angle measured from North).

  • zvec (numpy.ndarray, optional) – 3D vector specifying the direction of the rotated z axis.

  • offset (numpy.ndarray or Quantity, optional) – Static offset in Cartesian coordinates.

  • pot (Potential instance or list thereof) – The Potential instance or list thereof to rotate and tilt.

  • 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

  • 2021-03-29 - Started - Mackereth (UofT)

  • 2021-04-18 - Added inclination, sky_pa, galaxy_pa setup - Bovy (UofT)

  • 2022-03-14 - added offset kwarg - Mackereth (UofT)