Detection and Implications of Horizon-Scale Polarization in Sgr A*

          @misc{ pirsa_PIRSA:14110139,
            doi = {10.48660/14110139},
            url = {https://pirsa.org/14110139},
            author = {},
            keywords = {Strong Gravity},
            language = {en},
            title = {Detection and Implications of Horizon-Scale Polarization in Sgr A*},
            publisher = {Perimeter Institute},
            year = {2014},
            month = {nov},
            note = {PIRSA:14110139 see, \url{https://pirsa.org}}
          }
          

Abstract

The Event Horizon Telescope has measured compact emission in Sgr A* and M87 at resolutions comparable to their event horizons. Polarimetry with the EHT enables a powerful extension of this work, mapping magnetic field structures via the highly polarized synchrotron emission that is thought to dominate the compact emission. Sgr A* provides an especially attractive target for linear polarization studies with the EHT because it is unpolarized at the longer wavelengths where facility instruments are available. I will report on polarimetric results from our 2013 campaign, which demonstrate a sharp increase in the linear polarization fraction and variability of Sgr A* with increasing baseline. These data allow rich model-independent inferences about the polarization images and morphology and reveal that polarization is a sensitive probe of intrinsic variability.