Related papers: Deterministic Aspect of the $\gamma$-ray Variabili…
We study the relation between the mass accretion rate, the jet power, and the black hole mass of blazars. To this aim, we make use of the Sloan Digital Sky Survey (SDSS) and the 11 months catalog of blazars detected at energies larger than…
A key goal of radio and $\gamma-$ray observations of active galactic nuclei is to characterize their time variability in order to elucidate physical processes responsible for the radiation. I describe algorithms for relevant time series…
Blazars are a highly-variable, radio-loud subclass of active galactic nuclei (AGN). In order to better understand such objects we must be able to easily identify candidate blazars from the growing population of unidentified sources. Working…
We use advanced statistical tools of time-series analysis to characterize the dynamical complexity of the transition to optical wave turbulence in a fibre laser. Ordinal analysis and the horizontal visibility graph applied to the…
We study the long-term behavior of the bright gamma-ray blazar PKS 0402-362. Over a span of approximately 12.5 years, from August 2008 to January 2021, we gathered Fermi-LAT temporal data and identified three distinct periods of intense…
The Fermi Large Area Telescope (LAT) has detected more than 5000 gamma-ray sources in its first 8 years of operation. More than 3000 of them are blazars. About 60 per cent of the Fermi-LAT blazars are classified as BL Lacertae objects (BL…
We propose a scenario where blazars are classified as flat-spectrum radio quasars (FSRQs), BL Lacs, low synchrotron, or high synchrotron peaked objects according to a varying mix of the Doppler boosted radiation from the jet, the emission…
The strong variability of blazars can be characterized by power spectral densities (PSDs) and Fourier frequency-dependent time lags. In previous work, we created a new theoretical formalism for describing the PSDs and time lags produced via…
The extragalactic high-energy $\gamma$-ray sky is dominated by blazars, which are active galactic nuclei with their jets pointing towards us. Distance measurements are of fundamental importance yet for some of these sources are challenging…
The $\gamma-$ray emission from flat-spectrum radio quasars (FSRQs) is thought to be dominated by the inverse Compton scattering of the external sources of photon fields, e.g., accretion disk, broad-line region (BLR), and torus. FSRQs show…
We present an optical variability study of 44 newly identified blazar candidates behind the Magellanic Clouds, including 27 flat spectrum radio quasars (FSRQs) and 17 BL Lacertae objects (BL Lacs). All objects in the sample possess high…
The impact of the Fermi Gamma-ray Space Telescope on blazar research is reviewed. This includes a brief description of the Fermi Large Area Telescope, a summary of the various classes of extragalactic sources found in the First Large Area…
We present results from the first two years of our fast-cadence 15 GHz gamma-ray blazar monitoring program, part of the F-GAMMA radio monitoring project. Our sample includes the 1158 blazars north of -20 degrees declination from the…
Context: Being dominated by non-thermal emission from aligned relativistic jets, blazars allow us to elucidate the physics of extragalactic jets, and, ltimately, how the energy is extracted from the central black hole in radio-loud active…
Since mid-2007 we have carried out a dedicated long-term monitoring programme at 15 GHz using the Owens Valley Radio Observatory 40 meter telescope. One of the main goals of this programme is to study the relation between the radio and…
The radio properties of blazars detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope have been observed as part of the VLBA Imaging and Polarimetry Survey (VIPS). This large, flux-limited sample of active…
Quasi-periodic oscillations (QPO) originating from innermost regions of blazars can provide unique perspective of some of the burning issues in blazar studies including disk-jet connection, launch of relativistic jets from the central…
This work present the results of a multi-epoch observational study of the blazar S5\,1803+784, carried out from 2019 to 2023. The analysis is based on simultaneous data obtained from the Swift/UVOT/XRT, ASAS-SN, and Fermi-LAT instruments. A…
We address the highly debated issue of constraining the gamma-ray emission region in blazars from cross-correlation analysis using discrete correlation function between radio and gamma-ray light curves. The significance of the correlations…
The properties of blazar variability in the radio band are studied using the unique combination of temporal resolution from single dish monitoring and spatial resolution from VLBA imaging; such measurements, now available in all four Stokes…