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OJ 287 as a Rotating Helix

Cohen, Marshall H. (2017) OJ 287 as a Rotating Helix. Galaxies, 5 (1). Art. No. 12. ISSN 2075-4434. doi:10.3390/galaxies5010012.

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We present preliminary data from high-cadence 15-GHz VLBA images of OJ 287 from 1995 to 2015. The ridgelines suggest that the jet is rotating, perhaps with a period of∼30 years. The EVPA of the core rotated by 240° in 2001–2002 and decreased slowly after that. The inner jet apparently moved to a new direction after the rotation,as shown by the emergence of a new component at a new PA at 43 GHz, in 2004. This was presaged by a strong rise in the flux density of the core, and then its sudden fall as the new component was identified. The equivalent sequence of events took place about 5 years later at 15 GHz, but in addition the core EVPA had a step in 2006 and moved to be aligned with the new 43-GHz component. The 15-GHz core became optically thin in 2006, but the angular resolution was insufficient to separate the new component from the core until 2010.

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Additional Information:© 2017 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( Received: 6 September 2016 / Revised: 9 January 2017 / Accepted: 16 January 2017 / Published: 8 February 2017 (This article belongs to the Special Issue Blazars through Sharp Multi-wavelength Eyes) I am grateful to A. Pushkarev for calculating the ridgelines, and to the MOJAVE team for advice and suggestions. The authors declare no conflict of interest.
Errata:In an earlier paper it was erroneously stated that the inner jet of OJ 287 has a right-hand helical structure. In this addendum we show that the observations underlying this statement are ambiguous, and that they cannot determine the rotation sense.
Group:Astronomy Department
Subject Keywords:BL Lacertae objects: individual (OJ 287); galaxies: active; galaxies: jets; magnetohydrodynamics (MHD); waves
Issue or Number:1
Record Number:CaltechAUTHORS:20180430-101113523
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Official Citation:Cohen, M.H. OJ 287 as a Rotating Helix. Galaxies 2017, 5, 12.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:86119
Deposited By: George Porter
Deposited On:30 Apr 2018 21:22
Last Modified:15 Nov 2021 20:35

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