TY  - JOUR
A1  - Zhao, Guang-Yao
A1  - Gómez, José L.
A1  - Fuentes, Antonio
A1  - Krichbaum, Thomas P.
A1  - Traianou, Efthalia
A1  - Lico, Rocco
A1  - Cho, Ilje
A1  - Ros, Eduardo
A1  - Komossa, Stefanie
A1  - Akiyama, Kazunori
A1  - Asada, Keiichi
A1  - Blackburn, Lindy
A1  - Britzen, Silke
A1  - Bruni, Gabriele
A1  - Crew, Geoffrey
A1  - Dahale, Rohan
A1  - Dey, Lankeswar
A1  - Gold, Roman
A1  - Gopakumar, Achamveedu
A1  - Issaoun, Sara
A1  - Janssen, Michael
A1  - Jorstad, Svetlana
A1  - Kim, Jae-Young
A1  - Koay, Jun Yi
A1  - Kovalev, Yuri
A1  - Koyama, Shoko
A1  - Lobanov, Andrei
A1  - Loinard, Laurent
A1  - Lu, Ru-Sen
A1  - Markoff, Sera
A1  - Marscher, Alan P.
A1  - Martí-Vidal, Iván
A1  - Mizuno, Yosuke
A1  - Park, Jongho
A1  - Savolainen, Tuomas
A1  - Toscano, Teresa
T1  - Unraveling the Innermost Jet Structure of OJ 287 with the First GMVA + ALMA Observations
T2  - The astrophysical journal
N2  - 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.
KW  - Very long baseline interferometry
KW  - AGN host galaxies
KW  - Radio jets
KW  - Jets
KW  - Supermassive black holes
KW  - Radio continuum emission
Y1  - 2022
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/63180
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-631804
SN  - 1538-4357
N1  - 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).
N1  - 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.
VL  - 932
IS  - 1, art. 72
SP  - 1
EP  - 12
PB  - Institute of Physics Publ.
CY  - London
ER  -