iancze
commented
5 years ago 
Figure of HD 163296 from Isella et al. 2016.
The models are generated with RADMC3D using an axisymmetric disk surface density profile. Due to radiative transfer effects (disk optically thick), however, the moment-0 profile is not azimuthally symmetric. Hard to tell just how no axisymmetric the data emission actually is.
And, although the lanes are noticeable with the model due to the regular structure, they don't actually seem to be that high amplitude. We could always make a fiducial model with some chosen disk parameters and stellar mass, then see if whatever method we end up implementing actually is biased in anyway.
Think about how well a Nuker profile can represent the total intensity radial profiles of the disk. A good example of this type of profile is in Kastner et al. 18 re: V4046 Sgr.
Is this actually true in detail for all azimuthal angles of the disk? I.e., if we have an axisymmetric disk structure and temperature, when viewed in projection, is the total intensity profile radial axisymmetric too? It would seem as though if the disk were optically thick then this would be violated. This is something we can test directly with models and actual disk observations, so we should do this.
Then again, if this is a function of azimuth, then in theory we should be able to parameterize it based upon the projected viewpoint, i.e. this is sort of like looking through "airmass" in the disk.
What if the line emission is optically thick? We can only increase the total intensity when we get new emission when it shifts out of the line core.
What if the line emission is optically thin? We can only increase the total intensity with higher temps or more material or both.