相关论文: Is 0716+714 a superluminal blazar?

From 43GHz VLBA observations of the pair of radio sources 1928+738 and 2007+777 we have demonstrated the feasibility of precision phase-delay differential astrometric techniques at millimeter wavelengths. For a pair of sources with 5…

High resolution Very Long Baseline Interferometry (VLBI) observations of Active Galactic Nuclei (AGN) revealed traveling and stationary or quasi-stationary radio-components in several blazar jets. The traveling ones are in general…

The Global mm-VLBI Array (GMVA) is a network of 14 3\,mm and 7\,mm capable telescopes spanning Europe and the United States, with planned extensions to Asia. The array is capable of sensitive maps with angular resolution often exceeding…

Over the past two decades, our knowledge of the high-redshift (z > 5) radio quasars has expanded, thanks to dedicated high-resolution very long baseline interferometry (VLBI) observations. Distant quasars provide unique information about…

We analyze the parsec-scale jet kinematics from 2007 June to 2013 January of a sample of $\gamma$-ray bright blazars monitored roughly monthly with the Very Long Baseline Array at 43~GHz. In a total of 1929 images, we measure apparent…

Using the Urumqi 25m radio telescope, sources from the first three-month Fermi-LAT detected AGN catalog with declination >0 were observed in 2009 at 4.8 GHz. The radio flux density appears to correlate with the gamma-ray intensity.…

High redshift blazars are among the most powerful non-explosive sources in the Universe and play a crucial role in understanding the evolution of relativistic jets. To understand these bright objects, we performed a detailed investigation…

The presence of a relativistic jet in some radio-loud Narrow-Line Seyfert 1s (NLSy1) galaxies, first suggested by their variable radio emission and the flat radio spectra, is now confirmed by the Fermi-LAT detection of five NLSy1s in gamma…

Maps of the radio source 3C 120 obtained from VLBA+ observations at 8.4 GHz at five epochs in January - September 2002 are presented. The images were reconstructed using the maximum entropy method and the Pulkovo VLBImager software package…

We describe further observations of QSO J0906+6930, a z=5.48 blazar likely to be detected in gamma-rays. New radio and X-ray data place significant constraints on any kpc-scale extension of the VLBA-detected jet. Improved optical…

The $\gamma$-ray bright blazar CTA 102 is studied using imaging (new 15 GHz and archival 43 GHz Very Long Baseline Array, VLBA data) and time variable optical flux density, polarization degree and electric vector position angle (EVPA)…

We present a milliarcsecond-resolution radio survey of 17 high-redshift (4 < z < 5.4) blazar candidates observed with the European Very Long Baseline Interferometry (VLBI) Network at 5 GHz. The primary objective of this study was to…

Recent studies suggest that high-energy neutrinos can be produced in the jets of blazars, radio-loud active galactic nuclei (AGN) with jets pointing close to the line of sight. Due to the relatively poor angular resolution of current…

We present the first multi-frequency VLBA study of the quasar 0850+581 which appears to have a two-sided relativistic jet.Apparent velocity in the approaching jet changes from 3.4c to 7c with the separation from the core. The…

Opacity-driven shifts of the apparent VLBI core position with frequency (the "core shift" effect) probe physical conditions in the innermost parts of jets in active galactic nuclei. We present the first detailed investigation of this effect…

In this paper, we conduct a multi-frequency analysis of the gamma-ray bright blazar 1308+326 from February 2013 to March 2020, using the Korean VLBI Network at 22 and 43 GHz and gamma-ray data from the Fermi Large Area Telescope (LAT). Our…

We present results of simultaneous dual-frequency (2 GHz and 8 GHz) very long baseline interferometry (VLBI) observations of 12 active galactic nuclei with prominent jets. Spectral properties of the jets and evolution of their brightness…

I review observational properties of low power radio loud AGN. High resolution VLBI observations allow the estimate of the jet velocity and orientation with respect to the line of sight and the determination of the Doppler factor. These…

We report multifrequency observations of the $\gamma$-ray blazar 0528+134 with the Effelsberg 100-m telescope, the IRAM 30-m telescope, and the NRL Green Bank Interferometer. 0528+134 underwent a major radio and mm outburst in 1993 a few…

We present Chandra X-ray (0.2-8 keV) and Very Large Array radio (15 and 5 GHz) images of the $\gamma$-ray bright, superluminal quasar 0827+243. The X-ray jet bends sharply--by ~90 deg., presumably amplified by projection effects--5'' from…