Synchrotron intensity plots from a relativistic stratified jet

Frolova, V A; Nokhrina, E. E.; Pashchenko, I. N.

doi:10.1093/mnras/stad1381

Cited by 6 publications

(5 citation statements)

References 79 publications

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“…However, the presence of a bright core causes insufficient depolarization at the center of the jet, which is inconsistent with observations where the emission in the central peak is depolarized. Therefore, we conclude that it is necessary to consider models with the suppressed emission from the central core, consistent with the recent results from analytical MHD calculations (Frolova et al, 2023).…”

Section: Discussionsupporting

confidence: 90%

“…Comparison with observations of a resolved jets shows the radiation from the core are to be suppressed. Frolova et al (2023) demonstrate that, for example, this can be achieved through transverse stratification of the distribution of emitting particles, where only a small fraction of particles radiate up to a certain radius. One possible mechanism considered is the heating of emitting particles due to an Ohmic dissipation (Lyutikov et al, 2005).…”

Section: Discussionmentioning

confidence: 98%

“…Statistical analysis of flux-limited samples, including VLBI-kinematics, predicts a relatively small number of such objects (Vermeulen & Cohen, 1994;Cohen et al, 2007;Lister et al, 2019). However, this result is based on a jet model with constant Γ, which does not account for transverse velocity stratification (Komissarov et al, 2009;Beskin et al, 2017;Chatterjee et al, 2019), and apparently, the necessary transverse stratification of the distribution of emitting particles (Frolova et al, 2023).…”

Section: Discussionmentioning

confidence: 99%

“…Black contours of the linearly polarized intensity are given at 3σ P = 0.18 mJy/beam and also increase by a factor of 2. the observed bimodality of the EVPA direction in jets in the hollow jet model, where the core is naturally suppressed. However, Frolova et al (2023) show that although this model with a number density of emitting particles being proportional to the density of magnetic energy in the plasma structure is promising, it is unlikely as it leads to a strong dominance of the central core.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, Frolova et al (2023) studied the intensity profiles of the AGN jets based on magnetohydrodynamic (MHD) semi-analytic simulations using models with constant angular velocity and a total electric current closed inside the jet, as well as different mechanisms of "heating" the emitting particles. The authors showed that, in assumption that all particles in the jet are emitting, the transverse intensity profile is dominated by a dense core.…”

Section: Discussionmentioning

confidence: 99%

See 4 more Smart Citations

Simulations of Linear Polarization of Precessing Agn Jets at Parsec Scales

Todorov,

Kravchenko,

Pashchenko

et al. 2023

Astronomičeskij žurnal

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The latest results of the most detailed analysis of multi-epoch polarization-sensitive observations of active galactic nuclei (AGN) jets at parsecs scales by very long baseline interferometry (VLBI) reveal several characteristic patterns of linear polarization distribution and its variability [1, 2]. Some of the observed profiles can be reproduced by a simple model of a jet threaded by a helical magnetic field. However, none of the models presented to date can explain the observed polarization profiles with an increase in its degree towards the edges of the jet, and accompanied by a “fountain” type electrical vector pattern and its high temporal variability in the center. Based on simulations of the VLBI observations of relativistic jets, we show here that the observed transverse linear polarization profiles, atypical for the simple magnetic field models can be naturally produced assuming the finite resolution of VLBI arrays and precession of a jet on ten-years scales, observational indications of which are found in an increasing number of AGN. In our simulations, we qualitatively reproduce the distribution of the electric vector and its variability, though the polarization images are characterized by a bright spine due to weak smearing, which is poorly consistent with observations. More effective depolarization can be obtained in models with the suppressed emission of the jet spine.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 3 more Smart Citations

Simulations of Linear Polarization of Precessing Agn Jets at Parsec Scales

Todorov,

Kravchenko,

Pashchenko

et al. 2023

Astronomičeskij žurnal

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Properties of the jet in M87 revealed by its helical structure imaged with the VLBA at 8 and 15 GHz

Nikonov,

Kovalev,

Kravchenko

et al. 2023

Monthly Notices of the Royal Astronomical Society

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We present full-track high-resolution radio observations of the jet of the galaxy M87 at 8 and 15 GHz. These observations were taken over three consecutive days in 2009 May using the Very Long Baseline Array (VLBA), one antenna of the Very Large Array (VLA), and the Effelsberg 100 m telescope. Our produced images have dynamic ranges exceeding 20 000:1 and resolve linear scales down to approximately 100 Schwarzschild radii, revealing a limb-brightened jet and a faint, steep spectrum counter-jet. We performed jet-to-counter-jet analysis, which helped estimate the physical parameters of the flow. The rich internal structure of the jet is dominated by three helical threads, likely produced by the Kelvin–Helmholtz (KH) instability developing in a supersonic flow with a Mach number of approximately 20 and an enthalpy ratio of around 0.3. We produce a clean imaging bias-corrected 8–15 GHz spectral index image, which shows spectrum flattening in regions of helical thread intersections. This further supports the KH origin of the observed internal structure of the jet. We detect polarized emission in the jet at distances of approximately 20 milliarcseconds from the core and find Faraday rotation which follows a transverse gradient across the jet. We apply Faraday rotation correction to the polarization position angle and find that the position angle changes as a function of distance from the jet axis, which suggests the presence of a helical magnetic field.

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Core shift in parabolic accelerating jets

Nokhrina,

Pushkarev

2024

Monthly Notices of the Royal Astronomical Society

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The core shift method is a powerful method to estimate the physical parameters in relativistic jets from active galactic nuclei. The classical approach assumes a conical geometry of a jet and a constant plasma speed. However, recent observations showed that neither may hold close to the central engine, where plasma in a jet is effectively accelerating, and the jet geometry is quasi-parabolic. We modify the classical core shift method to account for these jet properties. We show that the core shift index may assume values in the range 0.8 − 1.2 or 0.53 − 0.8 depending on the jet geometry and viewing angle, with the indices close to both values are indeed being observed. We obtain the expressions to estimate jet magnetic field and a total magnetic flux in a jet. We show that the obtained magnetic field value can be easily recalculated down to the gravitational radius scales. For M 87 and NGC 315 these values are in good agreement with the ones obtained by different methods.

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Synchrotron intensity plots from a relativistic stratified jet

Cited by 6 publications

References 79 publications

Simulations of Linear Polarization of Precessing Agn Jets at Parsec Scales

Simulations of Linear Polarization of Precessing Agn Jets at Parsec Scales

Properties of the jet in M87 revealed by its helical structure imaged with the VLBA at 8 and 15 GHz

Core shift in parabolic accelerating jets

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