A wide and collimated radio jet in 3C84 on the scale of a few hundred gravitational radii

G. Giovannini*, T. Savolainen, M. Orienti, M. Nakamura, H. Nagai, M. Kino, M. Giroletti, K. Hada, G. Bruni, Y. Y. Kovalev, J. M. Anderson, F. D'Ammando, J. Hodgson, M. Honma, T. P. Krichbaum, S. S. Lee, R. Lico, M. M. Lisakov, A. P. Lobanov, L. PetrovB. W. Sohn, K. V. Sokolovsky, P. A. Voitsik, J. A. Zensus, S. Tingay

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Understanding the formation of relativistic jets in active galactic nuclei remains an elusive problem 1 .This is partly because observational tests of jet formation models suffer from the limited angular resolution of ground-based very-long-baseline interferometry that has thus far been able to probe the structure of the jet acceleration and collimation region in only two sources 2,3 . Here, we report observations of 3C84 (NGC 1275)-the central galaxy of the Perseus cluster-made with an interferometric array including the orbiting radio telescope of the RadioAstron 4 mission. The data transversely resolve the edge-brightened jet in 3C84 only 30 μas from the core, which is ten times closer to the central engine than was possible in previous ground-based observations 5 and allows us to measure the jet collimation profile from ~102 to ~104 gravitational radii (r g) from the black hole. The previously found 5, almost cylindrical jet profile on scales larger than a few thousand r g is seen to continue at least down to a few hundred r g from the black hole, and we find a broad jet with a transverse radius of â‰250 r g at only 350 r g from the core. This implies that either the bright outer jet layer goes through a very rapid lateral expansion on scales â‰102 r g or it is launched from the accretion disk.

Original languageEnglish
Pages (from-to)472-477
Number of pages6
JournalNature Astronomy
Issue number6
Publication statusPublished - 1 Jun 2018
MoE publication typeA1 Journal article-refereed


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