Related papers: Jet and accretion power in the most powerful Fermi…
Aims. A simplified model of jet power from active galactic nuclei is proposed in which the relationship between jet power and disk luminosity is discussed by combining disk accretion with two mechanisms of extracting energy magnetically…
Blazars are an extreme subclass of active galactic nuclei. Their rapid variability, luminous brightness, superluminal motion, and high and variable polarization are probably due to a beaming effect. However, this beaming factor (or Doppler…
The EGRET instrument on the Compton Gamma Ray Observatory (1991-2000) has positively detected high energy gamma-ray emission from more than 67 active galaxies of the blazar class. The majority of the EGRET blazars are flat-spectrum radio…
Since the launch of the Fermi satellite, BL Lacertae has been moderately active at gamma-rays and optical frequencies until May 2011, when the source started a series of strong flares. The exceptional optical sampling achieved by the…
A hyperaccretion disk formed around a stellar mass black hole is a plausible model for the central engine that powers gamma-ray bursts (GRBs). If the central black hole rotates and a poloidal magnetic field threads its horizon, a powerful…
Aiming to delineate the physical framework of blazars, we present an effective method to estimate four important parameters based on the idea proposed by \citet{BK95}, including the upper limit of central black hole mass $M$, the Doppler…
The detection of high-redshift ($z>$3) blazars enables the study of the evolution of the most luminous relativistic jets over cosmic time. More importantly, high-redshift blazars tend to host massive black holes and can be used to constrain…
We analyze X-ray light curves of the blazar Mrk 421 obtained from the Soft X-ray Imaging Telescope and the Large Area X-Ray Proportional Counter instrument onboard the Indian space telescope $AstroSat$ and archival observations from…
Blazars constitute the most enigmatic class of extragalactic gamma-ray sources, and their observational features have been ascribed to a relativistic jet closely aligned to the line of sight. They are generally divided in two main classes:…
The Energetic Gamma-Ray Experiment Telescope (EGRET) on the Compton Gamma-Ray Observatory (CGRO) discovered gamma-ray emission from more than 67 blazars during its 9 yr lifetime. We conducted an exhaustive search of the EGRET archives and…
The recent release of the First Fermi-LAT Source Catalog solidified the predominant association of extragalactic gamma-ray emitters to active galaxies, in particular blazars. A tight connection between AGN jet kinematics and gamma-ray…
The Fermi Gamma-ray Observatory discovered about a thousand extragalactic sources emitting energy from 100 MeV to 100 GeV. The majority of these sources belong to the class of blazars characterized by a quasi-featureless optical spectrum…
Gamma-ray luminosities of some quasar-associated blazars imply jet powers reaching values comparable to the accretion power even if assuming very strong Doppler boosting and very high efficiency of gamma-ray production. With much lower…
In 2008, the Fermi Gamma-ray Space Telescope has revealed - for the first time - high-energy (E > 100 MeV) gamma rays from a few Narrow-Line Seyfert 1 Galaxies (NLS1s). Later, in 2009 and 2010, two multifrequency campaigns on one of these…
The high redhsift blazars powered by supermassive black holes with masses exceeding $10^9\:M_\odot$ have the highest jet power and luminosity and are important probes to test the physics of relativistic jets at the early epochs of the…
(Abridged) We analyze blazar jet apparent speeds and accelerations from the RDV series of astrometric and geodetic VLBI experiments. From these experiments, we have produced and analyzed 2753 global VLBI images of 68 sources at 8 GHz with a…
Starting from the assumption that radio jets and accretion disks are symbiotic features present in radio loud and radio quiet quasars we scale the bulk power of radio jets with the accretion power by adding mass- and energy conservation of…
The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope routinely detects the highly dust-absorbed, reddened, and MeV-peaked flat spectrum radio quasar PKS 1830-211 (z=2.507). Its apparent isotropic gamma-ray luminosity…
We present multiwavelength data for twelve blazars observed from 2008-2010 as part of an ongoing optical-infrared photometric monitoring project. Sources were selected to be bright, southern (dec < 20 deg) blazars observed by the Fermi…
The correlation between the jet power and accretion disk luminosity is investigated and analyzed with our model for 7 samples of low luminosity active galactic nuclei (LLAGNs). The main results are: (1) the power-law correlation index…