Resolving the Base of the Relativistic Jet in M87 at 6Rsch Resolution with Global mm-VLBI
Max Planck Institut für Radioastronomie, Auf dem Hügel 69, Bonn D-53121, Germany
Institut de Radio Astronomie Millimétrique, 300 rue de la Piscine, Domaine Universitaire, Saint Martin d’Héres 38406, France
National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801, USA
Author to whom correspondence should be addressed.
Academic Editors: Jose L. Gómez, Alan P. Marscher and Svetlana G. Jorstad
Received: 15 July 2016 / Revised: 22 September 2016 / Accepted: 23 September 2016 / Published: 30 September 2016
M87 is one of the nearest radio galaxies with a central Super-Massive Black Hole (SMBH) and a prominent relativistic jet. Due to its close distance to the observer and the large SMBH mass, the source is one of the best laboratories to obtain strong observational constraints on the theoretical models for the formation and evolution of the AGN jets. In this article, we present preliminary results from our ongoing observational study about the innermost jet of M87 at an ultra-high resolution of ∼50
as achieved by the Global Millimeter-Very Long Baseline Interferometry Array (GMVA). The data obtained between 2004 and 2015 clearly show limb-brightened jets at extreme resolution and sensitivity. Our preliminary analysis reveals that the innermost jet expands in an edge-brightened cone structure (parabolic shape) but with the jet expansion profile slightly different from the outer regions of the jet. Brightness temperatures of the Very Long Baseline Interferometry (VLBI) core obtained from cm- to mm-wavelengths show a systematic evolution, which can be interpreted as the evolution as a function of distance from the BH. We also adopt an alternative imaging algorithm, Bi-Spectrum Maximum Entropy Method (BSMEM), to test reliable imaging at higher angular resolution than provided by the standard CLEAN method (i.e., super-resolution). A demonstration with a VLBA 7 mm example data set shows consistent results with a near-in-time 3 mm VLBI image. Application of the method to the 2009 GMVA data yields an image with remarkable fine-scale structures that have been never imaged before. We present a brief interpretation of the complexity in the structure.
This is an open access article distributed under the Creative Commons Attribution License
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
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MDPI and ACS Style
Kim, J.-Y.; Lu, R.-S.; Krichbaum, T.P.; Bremer, M.; Zensus, J.A.; Walker, R.C.; the M87 collaboration. Resolving the Base of the Relativistic Jet in M87 at 6Rsch Resolution with Global mm-VLBI. Galaxies 2016, 4, 39.
Kim J-Y, Lu R-S, Krichbaum TP, Bremer M, Zensus JA, Walker RC, the M87 collaboration. Resolving the Base of the Relativistic Jet in M87 at 6Rsch Resolution with Global mm-VLBI. Galaxies. 2016; 4(4):39.
Kim, Jae-Young; Lu, Ru-Sen; Krichbaum, Thomas P.; Bremer, Michael; Zensus, J. A.; Walker, R. C.; the M87 collaboration. 2016. "Resolving the Base of the Relativistic Jet in M87 at 6Rsch Resolution with Global mm-VLBI." Galaxies 4, no. 4: 39.
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