Analysis of these ALMA data by an unconventional fitting of belt models to dirty images placed apparently strong constraints on the structure. In particular, their analysis determined an inner edge too far out to be truncated by the outermost planet b and raised the possibility of the presence of an additional (and unseen) outer planet.

To better determine the properties of the cold belt of planetesimals in the HR 8799 system, we used the SMA to obtain new observations at 1.3 millimeters wavelength that are sensitive to larger angular scales than the previous millimeter interferometer studies by [@hughes11] and @booth16. We also obtained new observations at 9 millimeters wavelength with the Karl G. Jansky Very Large Array (VLA), to constrain the spectral index of the disk emission. In §2, we describe the details of these 1.3 millimeter and 9 millimeter observations. In §3, we present the 1.3 millimeter results in the form of images and deprojected visibility functions, and provide a quantitative analysis of these data using parametric model fits in an MCMC framework. In §4 we discuss implications of the new millimeter results for the system geometry, the mass of planet b, and the grain size distribution. In §5, 