**NEW in v1.2**: What’s new?¶

This page gives some of the key improvements in each galpy
version. See the `HISTORY.txt`

file in the galpy source for full
details on what is new and different in each version.

## v1.2¶

- Full support for providing inputs to all initializations, methods, and functions as astropy Quantity with units and for providing outputs as astropy Quantities.
`galpy.potential.TwoPowerTriaxialPotential`

, a set of triaxial potentials with iso-density contours that are arbitrary, similar, coaxial ellipsoids whose ‘radial’ density is a (different) power-law at small and large radii: 1/m^alpha/(1+m)^beta-alpha (the triaxial generalization of TwoPowerSphericalPotential, with flattening in the density rather than in the potential; includes triaxial Hernquist and NFW potentials.`galpy.potential.SCFPotential`

, a class that implements general density/potential pairs through the basis expansion approach to solving the Poisson equation of Hernquist & Ostriker (1992). Also implemented functions to compute the coefficients for a given density function. See more explanation here.`galpy.actionAngle.actionAngleTorus`

: an experimental interface to Binney & McMillan’s TorusMapper code for computing positions and velocities for given actions and angles. See the installation instructions for how to properly install this. See this section and the`galpy.actionAngle`

API page for documentation.`galpy.actionAngle.actionAngleIsochroneApprox`

(Bovy 2014) now implemented for the general case of a time-independent potential.`galpy.df.streamgapdf`

, a module for modeling the effect of a dark-matter subhalo on a tidal stream. See Sanders et al. (2016). Also includes the fast methods for computing the density along the stream and the stream track for a perturbed stream from Bovy et al. (2016).`Orbit.flip`

can now flip the velocities of an orbit in-place by specifying`inplace=True`

. This allows correct velocities to be easily obtained for backwards-integrated orbits.`galpy.potential.PseudoIsothermalPotential`

, a standard pseudo-isothermal-sphere potential.`galpy.potential.KuzminDiskPotential`

, a razor-thin disk potential.- Internal transformations between equatorial and Galactic coordinates are now performed by default using astropy’s coordinates module. Transformation of (ra,dec) to Galactic coordinates for general epochs.

## v1.1¶

- Full support for Python 3.
`galpy.potential.SnapshotRZPotential`

, a potential class that can be used to get a frozen snapshot of the potential of an N-body simulation.- Various other potentials:
`PlummerPotential`

, a standard Plummer potential;`MN3ExponentialDiskPotential`

, an approximation to an exponential disk using three Miyamoto-Nagai potentials (Smith et al. 2015);`KuzminKutuzovStaeckelPotential`

, a Staeckel potential that can be used to approximate the potential of a disk galaxy (Batsleer & Dejonghe 1994). - Support for converting potential parameters to NEMO format and units.
- Orbit fitting in custom sky coordinates.