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With the increased sensitivity and resolution of radio interferometry thestudy of the collimation and acceleration region of jets in Active GalacticNuclei (AGN) has come into focus within the last years. Whereas a largefraction of AGN jets reveal a change from parabolic to conical collimationaround the Bondi radius, a small number of sources deviate from this standardpicture, including the radio galaxy NGC1052. We study the jet width profile,which provides valuable information about the interplay between the centralengine and accretion disk system and the collimation and acceleration zone ofthe jets. We observed the double-sided active galaxy NGC1052 at six frequencieswith the VLBA in 2017 and at 22GHz with RadioAstron in 2016. These data arecombined with archival 15, 22, and 43 GHz multi-epoch VLBA observations. Fromridge-line fitting we obtained width measurements along the jet and counter-jetwhich were fitted with broken power-laws. We find a break in the jetcollimation profile at ~10^4 R_s (Schwarzschild radii). Downstream of the breakthe collimation is conical with a power-law index of 1.0 - 1.2 (cylindrical 0;parabolic 0.5; conical 1). The upstream power-law index of 0.36 for theapproaching jet is neither cylindrical nor parabolic and for the receding jetwith 0.16 close-to cylindrical. Both jets have an opening angle of ~30 degreeat a distance of ~10^3 R_S and are well collimated with an opening angle of <10degrees downstream of the break. There are significant differences in theupstream collimation profile between approaching (Eastern) and receding(Western) jet. Absorption or scattering in the surrounding torus as well as anaccretion wind may mimic a cylindrical profile. We need to increase theobserving frequencies, which do not suffer from absorption to find the true jetcollimation profile upstream of 10^4 R_s.

Ambilateral collimation study of the twin-jets in NGC1052