Kavli Affiliate: Bradford A. Benson
| First 5 Authors: Anne-Kathrin Baczko, Matthias Kadler, Eduardo Ros, Christian M. Fromm, Maciek Wielgus
| Summary:
Many active galaxies harbor powerful relativistic jets, however, the detailed
mechanisms of their formation and acceleration remain poorly understood. To
investigate the area of jet acceleration and collimation with the highest
available angular resolution, we study the innermost region of the bipolar jet
in the nearby low-ionization nuclear emission-line region (LINER) galaxy NGC
1052. We combined observations of NGC 1052 taken with VLBA, GMVA, and EHT over
one week in the spring of 2017. For the first time, NGC 1052 was detected with
the EHT, providing a size of the central region in-between both jet bases of
250 RS (Schwarzschild radii) perpendicular to the jet axes. This size estimate
supports previous studies of the jets expansion profile which suggest two
breaks of the profile at around 300 RS and 10000 RS distances to the core.
Furthermore, we estimated the magnetic field to be 1.25 Gauss at a distance of
22 {mu}as from the central engine by fitting a synchrotron-self absorption
spectrum to the innermost emission feature, which shows a spectral turn-over at
about 130 GHz. Assuming a purely poloidal magnetic field, this implies an upper
limit on the magnetic field strength at the event horizon of 26000 Gauss, which
is consistent with previous measurements. The complex, low-brightness,
double-sided jet structure in NGC 1052 makes it a challenge to detect the
source at millimeter (mm) wavelengths. However, our first EHT observations have
demonstrated that detection is possible up to at least 230 GHz. This study
offers a glimpse through the dense surrounding torus and into the innermost
central region, where the jets are formed. This has enabled us to finally
resolve this region and provide improved constraints on its expansion and
magnetic field strength.
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