two/three parameters for the disk density distribution ($R_{in}$, $R_{out}$ and $p$ for the two-boundary disk, or $R_{p}$ and $R_{w}$ for the Gaussian ring), two parameters for the disk viewing geometry ($i$ and P.A.), the total flux of the disk ($F_{tot}$), and three parameters for the point source ($\Delta x$, $\Delta y$ and the total flux $F_{pt}$). We determine the best-fit values for these free parameters independently by adopting the MCMC approach outlined in @macgregor13. For all parameters, we assume uniform priors and require that the model be physically plausible (flux greater than zero and the outer radius larger than the inner one).

The best-fit parameters and their $\pm$1$\sigma$ uncertainties are given in Table \[tab2\_mcmc\]. For each set of the best-fit parameters, we generated a high resolution model image and transformed it to the visibility domain according to the observation. We then constructed the residual map by subtracting the model from the data in the visibility domain and imaging the residual using the same procedures in MIRIAD. The residual maps are shown in Figure \[mcmc\_model\]. Overall, the residuals are within $\pm$3$\sigma$ for the main disk. The subtraction of the bright source is not perfect, and creates an over-subtraction at the center 