Related papers: Deterministic Aspect of the $\gamma$-ray Variabili…
We present multi-epoch observations from the Submillimeter Array (SMA) for a sample of 171 bright blazars, 43 of which were detected by Fermi during the first three months of observations. We explore the correlation between their gamma-ray…
We present results from four years of twice-weekly 15 GHz radio monitoring of about 1500 blazars with the Owens Valley Radio Observatory 40 m telescope. Using the intrinsic modulation index to measure variability amplitude, we find that,…
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…
With their jet pointing towards us, blazars are ideal tools to study the physics and structure of extragalactic jets. Their powerful jets are cosmic particle accelerators and are alleged to be one of the production sites of the high-energy…
Supermassive black holes at the centre of active galactic nuclei power some of the most luminous objects in the Universe. Typically, very long baseline interferometric (VLBI) observations of blazars have revealed only funnel-like…
Temporal analysis of blazar flux is a powerful tool to draw inferences about the emission processes and physics of these sources. In the most general case, the available light curves are irregularly sampled and influenced by gaps, and in…
We study a sample of 30 high-redshift blazars ($z>2.5$) by means of spectra and the radiation mechanism with Fermi Large Area Telescope $\gamma$-ray observations spanning 15 years. Three models -- the power law, power law with an…
A comprehensive analysis of quasi-periodic oscillations (QPOs) in the gamma-ray emissions of blazars. Utilizing 15 years of Fermi-LAT observations of seven blazars in our sample, we identify both long-term and transient quasi-periodic…
We present a first systematic time series study of a sample of blazars observed by the Transiting Exoplanet Survey Satellite $\textit{TESS}$ spacecraft. By cross matching the positions of the sources in the TESS observations with those from…
Variability in active galactic nuclei is observed in ultraviolet to X-ray emission based light curves. This could be attributed to orbital signatures of the plasma that constitutes the accretion flow on the putative disk or in the…
We present the results of the Fermi-Large Area Telescope (LAT) light curve (LC) modelling of selected blazars: six flat spectrum radio quasars (FSRQs) and five BL Lacertae (BL Lacs). All objects have densely sampled and long-term LCs, over…
Blazars are a class of active galactic nuclei (AGNs) known for their very rapid variabilty in the high energy regions of the electromagnetic spectrum. Despite this known fast variability, X-ray observations have generally not revealed…
In an optical monitoring program to characterize the variability properties of blazar, we observed 10 sources from the Roma-BZCAT catalogue for 26 nights in V and R bands during October 2014 to June 2015 with two telescopes located in…
We present a study on the detection and characterization of transient quasi-periodic oscillations (QPOs) in the $\gamma$-ray emission of blazars 4C +31.03, MG1 J123931+0443, and PKS 1622$-$253. Using light curves derived from \textit{Fermi}…
Radio emission in blazars -- the aligned subset of Active Galactic Nuclei (AGN) -- is produced by synchrotron electrons moving relativistically in their jet's magnetic field. Under the assumption of some degree of uniformity of the field,…
We conducted an analysis of gamma-ray variability in a large sample of jetted active galactic nuclei (AGNs) by utilizing archival Fermi-LAT light curves and applying damped random walk modeling to obtain variability amplitude. Our primary…
Recently, blazar 4C +27.50 was found to be flaring in gamma-rays since its detection with Fermi-LAT in 2008. For the first time, a dedicated temporal and spectral study of the blazar 4C +27.50 has been performed in this work to understand…
Blazars are the brightest and most abundant persistent sources in the extragalactic gamma-ray sky. Due to their significance, they are often observed across various energy bands to explore potential correlations between emissions at…
The exact location of the gamma-ray emitting region in blazars is still controversial. In order to attack this problem we present first results of a cross-correlation analysis between radio (11 cm to 0.8 mm wavelength, F-GAMMA program) and…
The analysis of eight EXOSAT X-ray lightcurves of six active galactic nuclei by nonlinear prediction methods indicates that the observed short time-scale variability is truly stochastic and is not caused by deterministic chaos. This result…