Deblurring Sgr A* Images

          @misc{ scivideos_PIRSA:14110105,
            doi = {10.48660/14110105},
            url = {https://pirsa.org/14110105},
            author = {},
            keywords = {Strong Gravity},
            language = {en},
            title = {Deblurring Sgr A* Images},
            publisher = {Perimeter Institute for Theoretical Physics},
            year = {2014},
            month = {nov},
            note = {PIRSA:14110105 see, \url{https://scivideos.org/pirsa/14110105}}
          }
          

Abstract

Scattering in the tenuous interstellar plasma blurs the image of Sgr A*. This effect decreases steeply with increasing frequency and becomes subdominant to the intrinsic emission structure at wavelengths close to a millimeter. I will discuss recent work that demonstrates how we can invert the blurring when properties of the scattering are known. With this technique, we can reconstruct the unscattered image of Sgr A* using EHT data. I will also show why some EHT observables -- such as closure phase and fractional polarization -- are largely immune to scattering. Finally, despite decades of study, there has been a recent flurry of progress in understanding the scattering properties, including studies of the Galactic Center magnetar and the discovery of refractive substructure in the scattering disk of Sgr A* at 1.3-cm wavelength. I will discuss these recent findings and their implications for imaging Sgr A* with the EHT