Addendum published on 28 May 2018, see Galaxies 2018, 6(2), 59.
OJ 287 as a Rotating Helix
Department of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA
Academic Editors: Jose L. Gómez, Alan P. Marscher and Svetlana G. Jorstad
Galaxies 2017, 5(1), 12; https://doi.org/10.3390/galaxies5010012
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)
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 View Full-Text
Keywords: BL Lacertae objects: individual (OJ 287); galaxies: active; galaxies: jets; magnetohydrodynamics (MHD); waves►▼ Show Figures
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MDPI and ACS Style
Cohen, M.H. OJ 287 as a Rotating Helix. Galaxies 2017, 5, 12.
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Cohen MH. OJ 287 as a Rotating Helix. Galaxies. 2017; 5(1):12.Chicago/Turabian Style
Cohen, Marshall H. 2017. "OJ 287 as a Rotating Helix." Galaxies 5, no. 1: 12.
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