English: First image of a black hole.
Top: EHT image of M87* from observations on 2019 April 11 as a representative example of the images collected in the 2019 campaign. The image is the average of three different imaging methods after convolving each with a circular Gaussian kernel to give matched resolutions. The largest of the three kernels (20 μas FWHM) is shown in the lower right. The image is shown in units of brightness temperature, ${\displaystyle {T}_{\rm {b}}=S{\lambda }^{2}/2{k}_{\rm {B}}{\rm {\Omega }}}$, where S is the flux density, λ is the observing wavelength, k_B is the Boltzmann constant, and Ω is the solid angle of the resolution element. Bottom: similar images taken over different days showing the stability of the basic image structure and the equivalence among different days. North is up and east is to the left.