cwitools.measurement.specific_ang_momentum

cwitools.measurement.specific_ang_momentum(vel_map, flx_map)

Calculate the specific angular momentum of an object.

j is defined here as SUM_xy(flux * |R_perp X v_z|) / SUM_xy(flux) where SUM_xy is summing over the spatial axes, R_perp is the projected radius from the flux-weighted center of mass of the emission, v_z is the average line-of-sight velocity in a spaxel and the X denotes the cross product.

Parameters:

• vel_map (numpy.ndarray) – 2D map of average velocity.
• dsp_map (numpy.ndarray) – 2D map of velocity dispersion.
• flx_map (numpy.ndarray) – 2D map of surface brightness/flux.

Returns:

The specific angular momentum, as defined above.

Return type:

float