The Event Horizon Telescope (EHT) has extended the Very Long Baseline Interferometry (VLBI) technique to mm wavelengths, achieving the highest angular resolution in the history of ground-based astronomy. Because an interferometer incompletely samples the visibility domain, the inverse problem of determining an image from a measured set of visibilities is ill-posed. While this issue affects all interferometers, it is particularly challenging for a sparse array like the EHT, due to the relatively small number of radiotelescopes capable of observing at high-radio frequencies.
In this talk, I will present some of the cutting-edge algorithms we have developed to reconstruct full Stokes interferometric images, including ‘dynamic’ solutions (i.e. movies) of fast-evolving sources such as SgrA*. We tested these algorithms both on synthetic and real data of SgrA*.
I will also discuss our initial search for transients and super-slow pulsars in the Galactic Center. Finally, I will describe plans for a new archive of Active Galactic Nuclei (AGN) observed in full-polarization with ALMA during VLBI campaigns. The archive will be open to the astronomical community and will contain science-ready products, including full-Stokes images, light curves, and tabulated polarization properties of the observed AGNs.