A transition from parabolic to conical shape as a common effect in nearby AGN jets

Y Y Kovalev, A B Pushkarev, E E Nokhrina, A V Plavin, V S Beskin, A V Chernoglazov, M L Lister, Tuomas Savolainen

Tutkimustuotos: LehtiartikkeliArticleScientificvertaisarvioitu

Abstrakti

Observational studies of collimation in jets in active galactic nuclei (AGN) are a key to understanding their formation and acceleration processes. We have performed an automated search for jet shape transitions in a sample of 367 AGN using VLBA data at 15 GHz and 1.4 GHz. This search has found ten out of 29 nearby jets at redshifts z < 0.07 with a transition from a parabolic to conical shape, while the full analyzed sample of 311 sources is dominated by distant AGN with a typical z ≈ 1. The ten AGN are UGC 00773, NGC 1052, 3C 111, 3C 120, TXS 0815−094, Mrk 180, PKS 1514+00, NGC 6251, 3C 371, and BL Lac. We conclude that the geometry transition may be a common effect in AGN jets. It can be observed only when sufficient linear resolution is obtained. Supplementing these results with previously reported shape breaks in the nearby AGN 1H 0323+342 and M87, we estimate that the break occurs at 105–106 gravitational radii from the nucleus. We suggest that the jet shape transition happens when the bulk plasma kinetic energy flux becomes equal to the Poynting energy flux, while the ambient medium pressure is assumed to be governed by Bondi accretion. In general, the break point may not coincide with the Bondi radius. The observational data supports our model predictions on the jet acceleration and properties of the break point.
AlkuperäiskieliEnglanti
JulkaisuMonthly Notices of the Royal Astronomical Society
DOI - pysyväislinkit
TilaHyväksytty/In press - 2020
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

Sormenjälki Sukella tutkimusaiheisiin 'A transition from parabolic to conical shape as a common effect in nearby AGN jets'. Ne muodostavat yhdessä ainutlaatuisen sormenjäljen.

  • Projektit

    • 3 Päättynyt

    Mustien aukkojen suihkut ja niiden fysiikka

    Chamani Velasco, W. & Savolainen, T.

    01/09/201724/09/2019

    Projekti: Academy of Finland: Other research funding

    Mustien aukkojen suihkut ja niiden fysiikka

    Savolainen, T.

    01/01/201624/09/2019

    Projekti: Academy of Finland: Other research funding

    Mustien aukkojen suihkut ja niiden fysiikka

    Savolainen, T. & Chamani Velasco, W.

    01/01/201631/08/2017

    Projekti: Academy of Finland: Other research funding

    Laitteet

  • Siteeraa tätä

    Kovalev, Y. Y., Pushkarev, A. B., Nokhrina, E. E., Plavin, A. V., Beskin, V. S., Chernoglazov, A. V., ... Savolainen, T. (Hyväksytty/painossa). A transition from parabolic to conical shape as a common effect in nearby AGN jets. Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnras/staa1121