A sensitive study of the peculiar jet structure HST-1 in M87
1 Instituto de Astrofísica de Andalucía, CSIC, Apartado 3004, 18080 Granada, Spain
2 INAF Istituto di Radioastronomia, via Gobetti 101, 40129 Bologna, Italy
3 Dipartimento di Astronomia, via Ranzani 1, 40127 Bologna, Italy
4 Department of Astronomical Science, The Graduate University for Advanced Studies (SOKENDAI), 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan
5 National Astronomical Observatory of Japan, Osawa, Mitaka, Tokyo, 181-8588, Japan
6 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
7 Departament d’Astronomia i Astrofisica, Universitat de València, Dr. Moliner 50, 46100 Burjassot, Valencia, Spain
a e-mail: firstname.lastname@example.org
Published online: 9 December 2013
To obtain a better understanding of the location and mechanisms for the production of the gamma-ray emission in jets of AGN we present a detailed study of the HST-1 structure, 0.8 arcsec downstream the jet ofM87, previously identified as a possible candidate for TeV emission. HST-1 shows a very peculiar structure with superluminal as well as possible stationary sub-components, and appears to be located in the transition from a parabolic to a conical jet shape, presumably leading to the formation of a recollimation shock. This scenario is supported by our new RHD simulations in which the interaction of a moving component with are collimation shock leads to the appearance of a new superluminal component. To discern whether HST-1 is produced by a recollimation shock or some other MHD instability, we present new polarimetric 2.2 and 5 GHz VLBA, as well as 15, 22 and 43 GHz JVLA observations obtained between November 2012 and March 2013.
© Owned by the authors, published by EDP Sciences, 2013
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