%0 Journal Article %J The Astrophysical Journal Letters %D 2019 %T First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole %A The EHT Collaboration et al. %B The Astrophysical Journal Letters %V 875 %P 1-17 %G eng %U https://iopscience.iop.org/article/10.3847/2041-8213/ab0ec7