of the bright source, and positive residuals in the area around it, suggesting the source might be extended . In all residual maps, there appears to be another faint (S/N$\sim$9) source $\sim$25 south of the bright one. The two axi-symmetric models yield very similar parameters in terms of the disk flux, viewing geometry and point source parameters. However, the residual in the main disk is slightly smaller in the Gaussian ring model. Although the residuals in the main disk tend to be more negative in the east side of the disk, unfortunately the bright source is along the west side of the major-axis, making it difficult to assess any asymmetric structure present in the disk (more detail is given in Section 4.2).

Imaging Plane Modeling Approach
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Given the good S/N detection of the main disk, we also try to derive the best-fit parameters for the two models by fitting in the image plane. Details about this approach can be found in @booth16. We use the combined synthesized map for the MCMC search. For experiments, two more free parameters are included in this part of the fitting. For both models, the center of the ring is not fixed at the 