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

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

来源：Nature Astronomy, 2018, 2(6): 472-477.

DOI：10.1038/s41550-018-0431-2

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 mu as 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 similar to 10(2) to similar to 10(4) gravitational radii (r(g)) from the black hole. The previously found(5), almost cylindrical jet profile on scales larger than a few thousand rg 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 greater than or similar to 250 r(g) at only >= 50 r(g) from the core. This implies that either the bright outer jet layer goes through a very rapid lateral expansion on scales less than or similar to 10(2) r(g) or it is launched from the accretion disk.

• 出版日期2018-6