I'm trying to wrap my head around dipole anisotropies of the Cosmic Microwave Background (CMB). I think my confusion is rooted in a misunderstanding of how multipole expansion is used in describing the anisotropy.
I know the CMB exhibits a basic anisotropy because 'we' are moving with respect to its rest frame. This manifests itself in a region of 'hot' redshifted CMB - which we are moving towards - and a 'cold' CMB region, which we are moving away from. This allows us to deduce the direction and speed of our local galactic cluster w.r.t to the CMB rest frame. There is also a smaller anisotropy that represents the unevenness of the early universe which shows no overall pattern.
This paper suggests that while the kinematic movement accounts for 99% of the dipole anisotropy, there is a secondary effect from these primordial fluctuations in the dipole:
Yet in this paper there is no mention of this. Instead, this source says these inflationary anisotropies only manifest themselves at higher 'multipoles'. This, in my mind, makes sense as describing all the unevenness requires a higher expansion.
I think my main question is ultimately this: is the dipole anisotropy a result only of our relative movement and the doppler effect ?
I understand this is in reference to spherical harmonics. For $ l = 100 $, does this mean that the anisotropy can only be explained with multiple expansions of the spherical harmonics?