spectral_density# astropy.units.equivalencies.spectral_density(wav, factor=None)[source]# Returns a list of equivalence pairs that handle spectral density with regard to wavelength and frequency. Parameters: wavQuantityQuantity associated with values being converted (e.g., wavelength or frequency). factorarray_likeIf wav is a UnitBase instead of a Quantity then factor is the value wav will be multiplied with to convert it to a Quantity. Deprecated since version 7.0: factor is deprecated. Pass in wav as a Quantity, not as a UnitBase.