Unraveling the Innermost Jet Structure of OJ 287 with the First GMVA + ALMA Observations

  • We present the first very long baseline interferometric (VLBI) observations of the blazar OJ 287 carried out jointly with the Global Millimeter VLBI Array (GMVA) and the phased Atacama Large Millimeter/submillimeter Array (ALMA) at 3.5 mm on 2017 April 2. The participation of phased ALMA has not only improved the GMVA north–south resolution by a factor of ∼3, but has also enabled fringe detections with signal-to-noise ratios up to 300 at baselines longer than 2 Gλ. The high sensitivity has motivated us to image the data with newly developed regularized maximum likelihood imaging methods, revealing the innermost jet structure with unprecedentedly high angular resolution. Our images reveal a compact and twisted jet extending along the northwest direction, with two bends within the inner 200 μas, resembling a precessing jet in projection. The component at the southeastern end shows a compact morphology and high brightness temperature, and is identified as the VLBI core. An extended jet feature that lies at ∼200 μas northwest of the core shows a conical shape, in both total and linearly polarized intensity, and a bimodal distribution of the linear polarization electric vector position angle. We discuss the nature of this feature by comparing our observations with models and simulations of oblique and recollimation shocks with various magnetic field configurations. Our high-fidelity images also enabled us to search for possible jet features from the secondary supermassive black hole (SMBH) and test the SMBH binary hypothesis proposed for this source.

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Author:Guang-Yao ZhaoORCiD, José L. GómezORCiDGND, Antonio FuentesORCiD, Thomas P. KrichbaumORCiD, Efthalia TraianouORCiDGND, Rocco LicoORCiD, Ilje ChoORCiD, Eduardo RosORCiDGND, Stefanie KomossaORCiDGND, Kazunori AkiyamaORCiD, Keiichi AsadaORCiD, Lindy BlackburnORCiD, Silke BritzenORCiDGND, Gabriele BruniORCiD, Geoffrey CrewORCiD, Rohan DahaleORCiD, Lankeswar DeyORCiDGND, Roman GoldORCiDGND, Achamveedu Gopakumar, Sara IssaounORCiD, Michael JanssenORCiD, Svetlana JorstadORCiDGND, Jae-Young KimORCiDGND, Jun Yi KoayORCiD, Yuri KovalevORCiD, Shoko KoyamaORCiD, Andrei LobanovORCiDGND, Laurent LoinardORCiD, Ru-Sen LuORCiDGND, Sera MarkoffORCiD, Alan P. MarscherORCiD, Iván Martí-VidalORCiD, Yosuke MizunoORCiD, Jongho ParkORCiD, Tuomas SavolainenORCiD, Teresa ToscanoORCiD
Parent Title (English):The astrophysical journal
Publisher:Institute of Physics Publ.
Place of publication:London
Document Type:Article
Date of Publication (online):2022/06/16
Date of first Publication:2022/06/16
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2023/04/03
Tag:AGN host galaxies; Jets; Radio continuum emission; Radio jets; Supermassive black holes; Very long baseline interferometry
Issue:1, art. 72
Article Number:72
Page Number:12
First Page:1
Last Page:12
The work at the IAA-CSIC is supported in part by the Spanish Ministerio de Economía y Competitividad (grants AYA2016-80889-P and PID2019-108995GB-C21), the Consejería de Economía, Conocimiento, Empresas y Universidad of the Junta de Andalucía (grant P18-FR-1769), the Consejo Superior de Investigaciones Científicas (grant 2019AEP112), and the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). This publication acknowledges the project M2FINDERS, which is funded by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No. 101018682).
This paper makes use of the following ALMA data: ADS/JAO.ALMA#2016.1.01116.V. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan), together with NRC (Canada), MOST and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. The ALMA data required nonstandard processing by the VLBI QA2 team (C. Goddi, I. Martí-Vidal, G. B. Crew, H. Rottmann, and H. Messias). This work is partially based on observations with the 100-m telescope of the MPIfR (Max-Planck-Institut für Radioastronomie) at Effelsberg. This research has made use of data obtained with the Global Millimeter VLBI Array (GMVA), which consists of telescopes operated by the MPIfR, IRAM, Onsala, Metsähovi, Yebes, the Korean VLBI Network, the Greenland Telescope, the Green Bank Observatory (GBT), and the Very Long Baseline Array (VLBA). The VLBA and the GBT are facilities of the National Science Foundation, operated under a cooperative agreement by Associated Universities, Inc. The data were correlated at the correlator of the MPIfR in Bonn, Germany.
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften
5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Licence (German):License LogoCreative Commons - CC BY - Namensnennung 4.0 International