trident.spectrum_generator.SpectrumGenerator.add_gaussian_noise

SpectrumGenerator.add_gaussian_noise(snr, seed=None)[source]

Postprocess a spectrum to add gaussian random noise of a given SNR.

Parameters

Snr:

float

The desired signal-to-noise ratio for determining the amount of gaussian noise

Seed:

optional, int

Seed for the random number generator. This should be used to ensure than the same noise is added each time the spectrum is regenerated, if desired. Default: None

Example

Make a one zone ray and generate a COS spectrum for it. Add noise to the spectrum as though it were observed with a signal to noise ratio of 30.

>>> import trident
>>> ray = trident.make_onezone_ray(redshift=0.5)
>>> sg = trident.SpectrumGenerator('COS')
>>> sg.make_spectrum(ray)
>>> sg.add_gaussian_noise(30)
>>> sg.plot_spectrum('spec_noise_corrected.png')

Plot a DLA with SNR of 10.

>>> import trident
>>> ray = trident.make_onezone_ray(column_densities={'H_p0_number_density':1e21})
>>> sg = trident.SpectrumGenerator(lambda_min=1200, lambda_max=1300, dlambda=0.1)
>>> sg.make_spectrum(ray, lines=['Ly a'])
>>> sg.add_gaussian_noise(10)
>>> sg.plot_spectrum('spec_noise.png')