Letter to the Editor

Magnetic collimation of the relativistic jet in M 87

¹ IASA and Section of Astrophysics, Astronomy and Mechanics, Department of Physics, University of Athens, Panepistimiopolis, 157 84 Zografos, Athens, Greece e-mail: jgracia@phys.uoa.gr
² Moscow Engineering Physics Institute (State University), Kashirskoje shosse 31, 115409 Moscow, Russia

Received: 5 August 2005
Accepted: 27 August 2005

Abstract

We apply a two-zone MHD model to the jet of M 87. The model consists of an inner relativistic outflow, which is surrounded by a non-relativistic outer disk-wind. The outer disk-wind collimates very well through magnetic self-collimation and confines the inner relativistic jet into a narrow region around the rotation axis. Further, we show by example, that such models reproduce very accurately the observed opening angle of the M 87 jet over a large range from the kiloparsec scale down to the sub-parsec scale.