Noise

We can control the white noise level of the detectors in a band with either an explicit noise-equivalent power level (in Watts) as

from maria import Band

my_band = Band(center=150, # in GHz
               width=30, # in GHz
               efficiency=0.5
               NEP=1e-15)

or with an implicit Rayleigh-Jeans sensitivity as

my_band = Band(center=150, # in GHz
               width=30, # in GHz
               efficiency=0.5
               NET_RJ=1e-5) # in K_RJ

or in CMB units as

my_band = Band(center=150, # in GHz
               width=30, # in GHz
               efficiency=0.5
               NET_CMB=1e-5) # in K_CMB

Since the sensitivity on the sky in temperature units depends on both the instrument and the observing conditions (i.e. the atmosphere), this method computes an NEP assuming there is no atmosphere. To include the effects of atmospheric opacity in this conversion, we can supply some spectrum_kwargs as

my_band = Band(center=150, # in GHz
               width=30, # in GHz
               efficiency=0.5, # in K_RJ
               spectrum_kwargs={"region": "chajnantor",
                                "zenith_pwv": 1e0, # in mm
                                "elevation": 45}) # in degrees

Non-white noise

Bolometers are typically dominated by non-white noise below a certain frequency threshold (the “knee”). We can add in pink noise to our band by supplying a knee parameter (in Hz).