High‐Frequency VLBI Imaging of the Jet Base of M87

Ly, Chun; Walker, R. C.; Junor, W.

doi:10.1086/512846

Cited by 156 publications

(225 citation statements)

References 33 publications

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“…A similar structural detail resembling a counterjet is also observed in the 43 GHz images of M 87 (Ly et al 2007;Walker et al 2008). The WISE analysis performed on the 43 GHz VLBA data has revealed several SSPs located in the counter-jet structure and moving outward with speeds similar to the subluminal speed measured on the jet side at the same distances from the core.…”

Section: Counter-jet and Jet Viewing Anglesupporting

confidence: 68%

Kinematics of the jet in M 87 on scales of 100–1000 Schwarzschild radii

Mertens

Lobanov

Walker

et al. 2016

A&A

235

266

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Context. Very long baseline interferometry (VLBI) imaging of radio emission from extragalactic jets provides a unique probe of physical mechanisms governing the launching, acceleration, and collimation of relativistic outflows. Aims. VLBI imaging of the jet in the nearby active galaxy M 87 enables morphological and kinematic studies to be done on linear scales down to ∼ 100 Schwarzschild radii (R s ). Methods. The two-dimensional structure and kinematics of the jet in M 87 (NGC 4486) have been studied by applying the Waveletbased Image Segmentation and Evaluation (WISE) method to 11 images obtained from multi-epoch Very Long Baseline Array (VLBA) observations made in January-August 2007 at 43 GHz (λ = 7 mm).Results. The WISE analysis recovers a detailed two-dimensional velocity field in the jet in M 87 at sub-parsec scales. The observed evolution of the flow velocity with distance from the jet base can be explained in the framework of MHD jet acceleration and Poynting flux conversion. A linear acceleration regime is observed up to z obs ∼ 2 mas. The acceleration is reduced at larger scales, which is consistent with saturation of Poynting flux conversion. Stacked cross correlation analysis of the images reveals a pronounced stratification of the flow. The flow consists of a slow, mildly relativistic layer (moving at β ∼ 0.5 c), associated either with instability pattern speed or an outer wind, and a fast, accelerating stream line (with β ∼ 0.92, corresponding to a bulk Lorentz factor γ ∼ 2.5). A systematic difference of the apparent speeds in the northern and southern limbs of the jet is detected, providing evidence for jet rotation. The angular velocity of the magnetic field line associated with this rotation suggests that the jet in M87 is launched in the inner part of the disk, at a distance r 0 ∼ 5 R s from the central engine.Conclusions. The combined results of the analysis imply that MHD acceleration and conversion of Poynting flux to kinetic energy play the dominant roles in collimation and acceleration of the flow in M 87.

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Section: Counter-jet and Jet Viewing Anglesupporting

confidence: 68%

Kinematics of the jet in M 87 on scales of 100–1000 Schwarzschild radii

Mertens

Lobanov

Walker

et al. 2016

A&A

235

266

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“…We have taken the core to be coincident with the brightest component, for which we have also detected circular polarization (Paper II); a faint counter-jet is observed not only at 2 cm ) but also with higher resolution at 13 and 7 mm (Ly et al 2007).…”

Section: Two-sided Jetsmentioning

confidence: 97%

Mojave: Monitoring of Jets in Active Galactic Nuclei With Vlba Experiments. V. Multi-Epoch Vlba Images

Lister

Aller

et al. 2009

The Astronomical Journal

344

136

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We present images from a long-term program (MOJAVE: Monitoring of Jets in active galactic nuclei (AGNs) with VLBA Experiments) to survey the structure and evolution of parsec-scale jet phenomena associated with bright radio-loud active galaxies in the northern sky. The observations consist of 2424 15 GHz Very Long Baseline Array (VLBA) images of a complete flux-density-limited sample of 135 AGNs above declination −20 • , spanning the period 1994 August to 2007 September. These data were acquired as part of the MOJAVE and 2 cm Survey programs, and from the VLBA archive. The sample-selection criteria are based on multiepoch parsec-scale (VLBA) flux density, and heavily favor highly variable and compact blazars. The sample includes nearly all the most prominent blazars in the northern sky, and is well suited for statistical analysis and comparison with studies at other wavelengths. Our multi-epoch and stacked-epoch images show 94% of the sample to have apparent one-sided jet morphologies, most likely due to the effects of relativistic beaming. Of the remaining sources, five have two-sided parsec-scale jets, and three are effectively unresolved by the VLBA at 15 GHz, with essentially all of the flux density contained within a few tenths of a milliarcsecond.

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“…The jet images were edge-brightened in a similar way because it is observed in the M 87 jet (e.g., Ly et al 2007). The next logical step is thus to scale the same model to M 87 to test if the model can reproduce the radio observations of the M 87 jet.…”

Section: Introductionmentioning

confidence: 99%

General relativistic magnetohydrodynamical simulations of the jet in M 87

Mościbrodzka

Falcke

Shiokawa

2016

A&A

308

314

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Context. The connection between black hole, accretion disk, and radio jet can be constrained best by fitting models to observations of nearby low-luminosity galactic nuclei, in particular the well-studied sources Sgr A* and M 87. There has been considerable progress in modeling the central engine of active galactic nuclei by an accreting supermassive black hole coupled to a relativistic plasma jet. However, can a single model be applied to a range of black hole masses and accretion rates? Aims. Here we want to compare the latest three-dimensional numerical model, originally developed for Sgr A* in the center of the Milky Way, to radio observations of the much more powerful and more massive black hole in M 87. Methods. We postprocess three-dimensional GRMHD models of a jet-producing radiatively inefficient accretion flow around a spinning black hole using relativistic radiative transfer and ray-tracing to produce model spectra and images. As a key new ingredient in these models, we allow the proton-electron coupling in these simulations depend on the magnetic properties of the plasma. Results. We find that the radio emission in M 87 is described well by a combination of a two-temperature accretion flow and a hot single-temperature jet. Most of the radio emission in our simulations comes from the jet sheath. The model fits the basic observed characteristics of the M 87 radio core: it is "edge-brightened", starts subluminally, has a flat spectrum, and increases in size with wavelength. The best fit model has a mass-accretion rate ofṀ ∼ 9 × 10 −3 M yr −1 and a total jet power of P j ∼ 10 43 erg s −1 . Emission at λ = 1.3 mm is produced by the counter-jet close to the event horizon. Its characteristic crescent shape surrounding the black hole shadow could be resolved by future millimeter-wave VLBI experiments. Conclusions. The model was successfully derived from one for the supermassive black hole in the center of the Milky Way by appropriately scaling mass and accretion rate. This suggests the possibility that this model could also apply to a wider range of low-luminosity black holes.

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High‐Frequency VLBI Imaging of the Jet Base of M87

Cited by 156 publications

References 33 publications

Kinematics of the jet in M 87 on scales of 100–1000 Schwarzschild radii

Kinematics of the jet in M 87 on scales of 100–1000 Schwarzschild radii

Mojave: Monitoring of Jets in Active Galactic Nuclei With Vlba Experiments. V. Multi-Epoch Vlba Images

General relativistic magnetohydrodynamical simulations of the jet in M 87

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