Related papers: Radio Evidence for AGN Activity: Relativistic as T…
We discuss results from a decade long program to study the fine-scale structure and the kinematics of relativistic AGN jets with the aim of better understanding the acceleration and collimation of the relativistic plasma forming AGN jets.…
Active galactic nuclei (AGN) have been observed as far as redshift z~7. They are crucial in investigating the early Universe as well as the growth of supermassive black holes at their centres. Radio-loud AGN with their jets seen at a small…
(abridged) Relativistic jets, formed in the vicinity of central supermassive black holes in AGN, show ample evidence connecting them to physical conditions in the accretion disc and broad-line region. The jets are responsible for a large…
Blazars are a subclass of radio-loud active galactic nuclei (AGNs), where the jet is aligned close to the line of sight. Blazars emission is dominated by non-thermal processes, where Doppler boosted radiation originates from a relativistic…
We present multi-epoch, parsec-scale core brightness temperature observations of 447 AGN jets from the MOJAVE and 2cm Survey programs at 15 GHz from 1994 to 2019. The brightness temperature of each jet over time is characterized by its…
High resolution radio observations remain the most direct way to study the formation and evolution of radio jets associated with the accretion onto massive black holes. We report preliminary results of our seven year VLBA observational…
We investigate the relativistic jet of the powerful radio-emitting blazar J1429+5406 at redshift z=3.015. Our understanding of jet kinematics in z>3 quasars is still rather limited, based on a sample of less than about 50 objects. The…
In its first three months of operations, the Fermi Gamma-Ray Observatory has detected approximately one quarter of the radio-flux-limited MOJAVE sample of bright flat-spectrum active galactic nuclei (AGNs) at energies above 100 MeV. We have…
Highly relativistic jets are most probably driven by strong magnetic fields and launched from the accretion disk surrounding a central black hole. Applying the jet flow parameters (velocity, density, temperature) calculated from the…
Aims. The X-ray luminous and radio-loud AGN SRGE J170245.3+130104 discovered at z $\sim$ 5.5 provides unique chances to probe the SMBH growth and evolution with powerful jets in the early Universe. Methods. We present 1.35 - 5.1 GHz Very…
Relativistic jets are one of the most powerful manifestations of the release of energy related to the supermassive black holes at the centre of active galactic nuclei (AGN). Their emission is observed across the entire electromagnetic…
Blazars are thought to possess a relativistic jet that is pointing toward the direction of the Earth and the elect of relativistic beaming enhances its apparent brightness. They radiate in all wavebands from the radio to the gamma-ray bands…
Using high-resolution radio imaging with VLBI techniques, the TANAMI program has been observing the parsec-scale radio jets of southern (declination south of -30{\deg}) gamma-ray bright AGN simultaneously with Fermi/LAT monitoring of their…
Blazars, radio-loud active galactic nuclei with the relativistic jet closely aligned with the line of sight, dominate the extragalactic sky observed at gamma-ray energies, above 100 MeV. We discuss some of the emission properties of these…
Relativistic effects dominate the emission of blazar jets complicating our understanding of their intrinsic properties. Although many methods have been proposed to account for them, the variability Doppler factor method has been shown to…
We report the results of a 15 GHz (2 cm) multi-epoch VLBA program, begun in 1994 to study the outflow in radio jets ejected from quasars and active galaxies. The observed flow of 208 distinct features measured in 110 quasars, active…
Quasars with flat radio spectra and one-sided, arc-second scale, ~100 mJy GHz radio jets are found to have similar scale X-ray jets in about 60% of such objects, even in short 5 to 10 ks Chandra observations. Jets emit in the GHz band via…
The existence of accreting supermassive black holes up to billions of solar masses at early cosmological epochs (in the context of this work, redshifts z>=6) requires very fast growth rates which is challenging to explain. The presence of a…
The idea that the radio jets in AGN contain material in relativistic motion is supported by many lines of observational evidence, including morphology, brightness temperature estimated with interferometers and with intrinsic variations,…
Up to now, jet kinematic studies of radio quasars have barely reached beyond the redshift range at $z>3.5$. This significantly limits our knowledge of high-redshift jets, which can provide key information for understanding the jet nature…