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The radio velocity convention
If the radial velocity is negligeable compared to the light velocity, we
obtain to first order
 |
(68) |
In this case, we can establish a linear velocity scale (see
Sect.
)
 |
(69) |
This linear velocity scale is only a first order approximation, which is
called the radio velocity convention. Indeed, it is well adapted to the
radio spectrometer because 1) their natural output is a spectral axis
regularly spaced in frequency and 2) the radio velocity convention gives a
linear relation between the velocity and the frequency scale. This is why
this convention is the default in CLASS.
Gildas manager
2023-06-01