TY - JOUR
T1 - Pinpoint the jet apex in 3C 84
AU - Paraschos, G. F.
AU - Kim, J. Y.
AU - Krichbaum, T. P.
AU - Oh, J.
AU - Hodgson, J. A.
AU - Gurwell, M. A.
AU - Zensus, J. A.
N1 - Publisher Copyright:
© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0).
PY - 2021
Y1 - 2021
N2 - Jets which are powered by an AGN are a crucial element in the study of their central black holes (BH) and their immediate surroundings. The formation of such jets is the subject of intense research, mainly based on the dichotomy presented by the two main jet launching scenarios - the one from Blandford & Payne (1982), and the one from Blandford & Znajek (1977). In this work we study the prominent and nearby radio galaxy 3C 84 (NGC 1275) with 15, 43, and 86 GHz quasi-simultaneous VLBI observations. From these we determine the jet apex to be located 83 ± 7 μas (0.028 - 0.11 pc) upstream of the 86 GHz VLBI core, applying a two dimensional cross-correlation analysis. A byproduct of this analysis are spectral index maps, in which we identify a robust spectral index gradient in the north-south direction, for the first time at such high resolution, for the 43-86 GHz pair. The magnetic field strength at distances from the VLBI core comparable to measurements from the literature (∼ 10 Schwarzschild radii) for other prominent AGN, like NGC 1052 and M 87, is computed to be 70 - 600 G. Implications for the magnetic field topology are also discussed.
AB - Jets which are powered by an AGN are a crucial element in the study of their central black holes (BH) and their immediate surroundings. The formation of such jets is the subject of intense research, mainly based on the dichotomy presented by the two main jet launching scenarios - the one from Blandford & Payne (1982), and the one from Blandford & Znajek (1977). In this work we study the prominent and nearby radio galaxy 3C 84 (NGC 1275) with 15, 43, and 86 GHz quasi-simultaneous VLBI observations. From these we determine the jet apex to be located 83 ± 7 μas (0.028 - 0.11 pc) upstream of the 86 GHz VLBI core, applying a two dimensional cross-correlation analysis. A byproduct of this analysis are spectral index maps, in which we identify a robust spectral index gradient in the north-south direction, for the first time at such high resolution, for the 43-86 GHz pair. The magnetic field strength at distances from the VLBI core comparable to measurements from the literature (∼ 10 Schwarzschild radii) for other prominent AGN, like NGC 1052 and M 87, is computed to be 70 - 600 G. Implications for the magnetic field topology are also discussed.
UR - http://www.scopus.com/inward/record.url?scp=85129764320&partnerID=8YFLogxK
M3 - Conference article
AN - SCOPUS:85129764320
SN - 1824-8039
VL - 399
JO - Proceedings of Science
JF - Proceedings of Science
M1 - 043
T2 - 2021 European VLBI Network Mini-Symposium and Users' Meeting, EVN 2021
Y2 - 12 July 2021 through 14 July 2021
ER -