Related papers: From Centimeter to Millimeter Wavelengths: A High …
Aims. The high energy spectrum of 3C 273 is usually understood in terms of inverse-Compton emission in a relativistic leptonic jet. This model predicts variability patterns and delays that could be tested with simultaneous observations from…
We present the first space VLBI observations of 3C~371, carried out at a frequency of 4.8 GHz. The combination of the high resolution provided by the orbiting antenna Highly Advanced Laboratory for Communications and Astronomy (HALCA) and…
Variations of the optical continuum emission in the radio galaxy 3C 390.3 are compared to the properties of radio emission from the compact, sub-parsec-scale jet in this object. We showed that very long-term variations of optical continuum…
The quasar 3C345 is one of the best examples of extragalactic jet with superluminal components moving on helical paths. To get better constraints on the jet physics, we have imaged the source at the highest possible resolution, using…
3C 454.3 is a flat spectrum radio quasar (FSRQ) known for its high variability across the electromagnetic spectrum, showing structural and flux variability in its pc-scale jet, and correlated variability among frequency bands. This study…
We present a study of sub-pc scale radio structure of the radio galaxy 3C 84/NGC 1275 based on the Very Long Baseline Array (VLBA) data at 43 GHz. We discover a limb-brightening in the "restarted" jet associated with the 2005 radio…
We study the most central regions of AGN jets with an angular resolution of tens of micro-arcseconds using VLBI at millimeter wavelengths (mm-VLBI). We present and discuss a new 86 GHz VLBI survey of compact radio sources. We show new high…
The mechanism and the region of generation of variable continuum emission are poorly understood for radio-loud AGN because of a complexity of the nuclear region. High-resolution radio VLBI (very long baseline interferometry) observations…
We present new results on the parsec-scale jet of the quasar 3C395, derived from VLBI polarization sensitive observations made in 1995.91 and 1998.50 at 8.4, 15.4 and 22.2 GHz. The observations show a complex one-sided jet extending up to…
Relativistic jets originating at the center of AGN are embedded in extreme environments with strong magnetic fields and high particle densities, which makes them a fundamental tool for studying the physics of magnetized plasmas. We aim to…
There is still a limited number of high-redshift ($z>3$) active galactic nuclei (AGN) whose jet kinematics have been studied with very long baseline interferometry (VLBI). Without a dedicated proper motion survey, regularly conducted…
Relativistic jets launched by active galactic nuclei are fundamental for understanding the physics of accreting supermassive black holes and their immediate environment, yet the mechanisms driving jet launching remain uncertain. In this…
We present an update of 3C 273's database hosted by the ISDC, completed with data from radio to gamma-ray observations over the last 10 years. We use this large data set to study the multiwavelength properties of this quasar,especially…
The apparent position of the "core" in a parsec-scale radio jet (a compact, bright emitting region at the narrow end of the jet) depends on the observing frequency, owing to synchrotron self-absorption and external absorption. While…
Observational studies of GHz peaked spectrum (GPS) sources contribute to the understanding of the radiative properties and interstellar environment of host galaxies. We present the results from the multi-frequency high-resolution VLBI…
Multi-frequency Very Long Baseline Array (VLBA) polarimetry observation of the GHz-Peaked Spectrum (GPS) quasar OQ172 (J1445+0958) has been performed at 1.6, 2.2, 4.8, 8.3 and 15.3 GHz in 2005. Core-jet structures are detected in all bands…
Results are presented from long term VLBI monitoring of the parsec-scale radio jet in 3C120, primarily at 5 and 1.7 GHz. Numerous superluminal features are followed, some over large fractional distances from the core. The speeds of the…
We use a combination of high-resolution very long baseline interferometry (VLBI) radio and multi-wavelength flux density and polarization observations to constrain the physics of the dissipation mechanism powering the broadband flares in 3C…
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…
High-resolution millimeter wave very-long-baseline interferometry (mm-VLBI) is an ideal tool for probing the structure at the base of extragalactic jets in detail. The TeV blazar Mrk 501 is one of the best targets among BL Lac objects for…