SpectralData

The madcubapy.coordinates package offers a set of utility functions to work with spectral data.

Using the SpectralData class

SpectralData is a wrapper for Astropy’s SpectralCoord that lets the user specify the input data as the rest frequency instead of observed frequency.

We can initialize a SpectralData instance using a value and a unit, or a Quantity object:

>>> from madcubapy.coordinates import SpectralData
>>> sd = SpectralData((266, 267) * u.GHz,
                    frame_type="rest",
                    radial_velocity=50 * u.km / u.s,)
>>> sd
[265.95564, 266.95547] GHz

Note that the representation of SpectralData and SpectralCoord is the observed frequency corresponding to the input rest frequency and radial velocity.

We can obtain the rest frequency again with:

>>> sd.to_rest()
[266, 267] GHz

We can obtain the array in velocity by providing the rest frequency and doppler convention (the doppler_rest and doppler_convention parameters can also be set when initializing the SpectralData object).

>>> sd.to(u.km / u.s, doppler_rest=267.01 * u.GHz, doppler_convention="radio")
[1183.8106, 61.22172] km / s

Extra functionality

Since this class is based on SpectralCoord, it retains all of its functionality. Check the Using SpectralCoord page for an overview on all of its functionality.