相关论文: Core shift in parabolic accelerating jets

Active Galactic Nucleus jets have long be thought to exhibit a conical jet shape, but recently, several jets were found to have a transition from parabolic to conical structure. As more sources are investigated, this collimation profile…

We report multi-frequency VLBI studies of the sub-parsec scale structure of the two-sided jet in the nearby radio galaxy NGC 4261. Our analyses include new observations using the Source Frequency Phase Referencing technique with the Very…

Recently it was shown that the centrifugal instability may be important in the dynamics of astrophysical jets undergoing reconfinement by external pressure. However, these studies were limited to the case of unmagnetised flows. Here we…

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. The two-dimensional…

Accurate measurement of the frequency-dependent shift of the self-absorbed radio core is required for multi-frequency analysis of VLBI data since absolute positional information is lost as a result of phase self-calibration. We use the…

We present sub-milliarcsecond resolution total intensity and linear polarization VLBI images of 3C273, using concurrent 43 and 86 GHz data taken with the Very Long Baseline Array in May 2002. The structure seen in the innermost jet suggest…

We report new results from an HST archival program to study proper motions in the optical jet of the nearby radio galaxy M87. Using over 13 years of archival imaging, we reach accuracies below 0.1c in measuring the apparent velocities of…

We present total and polarized intensity images of 15 active galactic nuclei obtained with the Very Long Baseline Array at 7 mm at 17 epochs from 1998 March to 2001 April. At some epochs the images are accompanied by nearly simultaneous…

The structure and dynamics of the M87 jet from sub-milli-arcsec to arcsecond scales are continuously examined. We analysed the VLBA archival data taken at 43 and 86 GHz to measure the size of VLBI cores. Millimeter/sub-mm VLBI cores are…

Several observations of astrophysical jets show evidence of a structure in the direction perpendicular to the jet axis, leading to the development of "spine & sheath" models of jets. Most studies focus on a two-component jet consisting of a…

We study the formation and evolution of jets in the solar atmosphere using numerical simulations of partially ionized plasma. The two-fluid magnetohydrodynamic equations with ion+electron and neutral hydrogen components are used in…

Using the numerical data of MHD simulation for AGN jets based on our ``sweeping magnetic twist model'', we calculated the Faraday rotation measure (FRM) and the Stokes parameters to compare with observations. We propose that the FRM…

Several multi-frequency polarization studies have shown the presence of systematic Faraday Rotation gradients across the parsec-scale jets of Active Galactic Nuclei (AGN), taken to be due to the systematic variation of the line-of-sight…

In this paper, we investigate the magnetohydrodynamical structure of a jet powered by a spinning black hole, where electromagnetic fields and fluid motion are governed by the Grad-Shafranov equation and the Bernoulli equation, respectively.…

Because of its proximity and the large size of its black hole, M87 is one of the best targets for studying the launching mechanism of active galactic nucleus jets. Currently, magnetic fields are considered to be an essential factor in the…

We apply our intrinsically symmetrical, decelerating relativistic jet model to deep VLA imaging of the inner 140 arcsec of the giant low-luminosity radio galaxy NGC 315. An optimized model accurately fits the data in both total intensity…

The idea that systematic Faraday Rotation gradients across the parsec-scale jets of AGNs can reveal the presence of helical magnetic (B) fields has been around since the early 1990s. These gradients are taken to be due to the systematic…

We performed multi-frequency studies on the gigahertz-peaked spectrum high-redshift quasar 0858-279. Initially, the source presented itself in the early VLBI images as a very peculiar resolved blob. We observed the quasar with the VLBA at…

We explore the impact of "slow-light" radiative transfer - i.e., general relativistic radiative transfer (GRRT) calculations in which the simulated fluid evolves while light rays are propagating through it - in general relativistic…

The parsec-scale Faraday rotation measure (RM) distribution of six "blazars" is investigated using multi-frequency (4.6--43 GHz) polarization observations taken on 2006 July 2 with the VLBA. Analysis of the RM provides the direction of the…