Issue |
A&A
Volume 679, November 2023
|
|
---|---|---|
Article Number | L1 | |
Number of page(s) | 7 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202348037 | |
Published online | 30 October 2023 |
Letter to the Editor
The cylindrical jet base of M 87 within 100 μas of the central engine
1
1415 Granvia Altamira, Palos Verdes Estates, CA 90274, USA
e-mail: brian.punsly@cox.net
2
ICRANet, Piazza della Repubblica 10, Pescara 65100, Italy
3
ICRA, Physics Department, University La Sapienza, Roma, Italy
Received:
21
September
2023
Accepted:
10
October
2023
A recent article on high-resolution 86 GHz observations with the Global Millimeter VLBI Array, the phased Atacama Large Millimeter/submillimeter Array, and the Greenland Telescope describes the detection of a limb-brightened cylindrical jet, 25 μas < z < 100 μas, where z is the axial displacement from the supermassive black hole in the sky plane. It was shown to be much wider and much more collimated than 2D simulations of electromagnetic (Blandford-Znajek) jets from the event horizon predicted. This was an unanticipated discovery. The claimed detection of a jet connected to the accretion flow provides a direct observational constraint on the geometry and physics of the jet launching region for the first time in any black hole jetted system. This landmark detection warrants further analysis. This Letter focuses on the most rudimentary properties, the shape and size of the source of the detected jet emission, the determination of which is not trivial due to line-of-sight effects. Simple thick-walled cylindrical shell models for the source were analyzed to constrain the thickness of the jet wall. The analysis indicates a tubular jet source with a radius R ≈ 144 μas ≈ 38M and that the tubular jet walls have a width W ≈ 36 μas ≈ 9.5M, where M is the geometrized mass of the black hole (a volume comparable to that of the interior cavity). The observed cylindrical jet connects continuously to the highly limb-brightened jet (previously described as a thick-walled tubular jet) that extends to z > 0.65 mas, and the two are likely in fact the same outflow (i.e., from the same central engine).
Key words: galaxies: jets
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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