SatelliteAlignment

class halotools.empirical_models.SatelliteAlignment(satellite_alignment_strength=1.0, prim_gal_axis='major', **kwargs)

Bases: object

alignment model for satellite galaxies in sub-halos

Parameters:

satellite_alignment_strengthfloat

[-1,1] bounded number indicating alignment strength

prim_gal_axisstring, optional

string indicating which galaxy principle axis is correlated with the halo alignment axis. The options are: major, intermediate, and minor.

alignment_keyslist

A list of strings indicating the keywords for the x,y- and z components of the halo alignment vector. Deafult is [‘halo_axisA_x’, ‘halo_axisA_y’, ‘halo_axisA_z’].

Notes

If the kwargs or table contains a key “alignment_strength”, when populating a mock, this will be used instead of the satellite_alignment_stregth parameter passed during intialization. This is how varying the alignment strength as a function of galaxy/halo properties is handeled.

Methods Summary

assign_satellite_orientation(**kwargs)

Assign a set of three orthoganl unit vectors indicating the orientation of the galaxies' major, intermediate, and minor axis

Methods Documentation

assign_satellite_orientation(**kwargs)

Assign a set of three orthoganl unit vectors indicating the orientation of the galaxies’ major, intermediate, and minor axis

Parameters:

halo_axisA_x, halo_axisA_y, halo_axisA_zarray_like

x,y,z components of halo alignment axis

Returns:

major_aixs, intermediate_axis, minor_axisnumpy nd.arrays

arrays of galaxies’ axes