The putative center in NGC 1052

For the first time NGC 1052 was detected with the EHT, providing a size of the central region in-between both jet bases of 43uas perpendicular to the jet axes, corresponding to just around 250 RS (Schwarzschild radii). This size estimate supports previous studies of the jets expansion profile which suggest two breaks of the profile at around 3x10^3^RS and 1x10^4^RS distances to the core. Furthermore, we estimate the magnetic field to be 1.25 Gauss at a distance of 22uas from the central engine by fitting a synchrotron-self absorption spectrum to the innermost emission feature, which shows a spectral turn-over at ~130GHz.

Assuming a purely poloidal magnetic field this implies an upper limit on the magnetic field strength at the event horizon of 2.6x10^4^Gauss, which is consistent with previous measurements. The complex and low brightness, double-sided jet structure in NGC 1052 makes it challenging to detect the source at millimeter wavelength. However, our first EHT observations demonstrated that detection is possible up to at least 230GHz.

This enabled us to glimpse through the dense surrounding torus into the innermost central region where the jets are formed, to finally resolve this region and to give improved constraints on its expansion and magnetic field strength.