Related papers: Exploring the variability properties of gamma-ray …
We present a detailed study of flux and index distributions of three blazars (one FSRQ and two BL Lacs) by using 16 years of Rossi X-ray Timing Explorer archival data. The three blazars were chosen such that their flux and index…
The observed log-normal flux distributions in the high energy emission from blazars have been interpreted as being due to variability stemming from non-linear multiplicative processes generated dynamically from the accretion disc. On the…
Blazars can be detected from very large distances due to their high luminosity. However, the detection of $\gamma$-ray emission of blazars beyond $z=3$ has only been confirmed for a small number of sources. Such observations probe the…
We compare the \gamma-ray light curves of the blazars, constructed with data provided by the Fermi Large Area Telescope, with flux and polarization variations in the VLBI core and bright superluminal knots obtained via monthly monitoring…
Context. Monthly-binned gamma-ray light curves of 236 bright gamma-ray sources, particularly blazars, selected from a sample of 2278 high-galactic latitude objects observed with Fermi-LAT, show flux variability characterized by power…
The F-GAMMA program is among the most comprehensive programs that aim at understanding the physics in active galactic nuclei through the multi-frequency monitoring of Fermi blazars. Here we discuss monthly sampled broad-band radio spectra…
In the use and interpretation of $\log{N}$--$\log{S}$ distributions for gamma-ray bursts, burst peak flux has typically been used for $S$. We consider here the use of the fluence as a measure of $S$, which may be a more appropriate quantity…
The launching mechanism of the jets of active galactic nuclei is observationally poorly constrained, due to the large distances to these objects and the very small scales (sub-parsec) involved. In order to better constrain theoretical…
Flaring activity from the jets of active galactic nuclei has been studied for several decades, closely related to the loading and evolution of the jet. In this work, we focus on the sub-hundred parsec jet region, well traced by non-thermal…
Flat spectrum radio quasars (FSRQs) are the most luminous blazars at GeV energies, but only rarely emit detectable fluxes of TeV gamma rays, typically during bright GeV flares. We explore the gamma-ray variability and spectral…
We use the BD2 sample of gamma-ray bursts (GRBs) based on 5.9 years of BATSE DISCLA data with a variety of models of the luminosity function to derive characteristic GRB luminosities, space densities and redshift distributions. Previously…
We report the results of optical monitoring for a sample of 11 blazars including 10 BL Lacs and 1 Flat Spectrum Radio Quasar (FSRQ). We have measured the multiband optical flux and colour variations in these blazars on intra-day and…
Prompted by recent discoveries of log-normal distributions in gamma-ray/X-ray temporal variabilities of gamma-ray bursts (GRBs) and blazars, we re-examine the X-ray variability of Cygnus X-1 in the hard/low state using Ginga data in 1990.…
S5 0716+714 is a typical BL Lacertae object. In this paper we present the analysis and results of long term simultaneous observations in the radio, near-infrared, optical, X-ray and $\gamma$-ray bands, together with our own photometric…
Characterisation of the long-term variations in the broad line region in a luminous blazar, where Comptonisation of broad-line emission within a relativistic jet is the standard scenario for production of gamma-ray emission that dominates…
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…
Blazars are the most active extragalactic gamma-ray sources. They show sporadic bursts of activity, lasting from hours to months. In this work we present a 10-year analysis of a sample of bright sources detected by Fermi-LAT (100 MeV - 300…
We study the ensemble optical variability of 276 FSRQs and 86 BL Lacs in the Palomar-QUEST Survey with the goal of searching for common fluctuation properties, examining the range of behavior across the sample, and characterizing the…
In this work, I have presented a multi-frequency variability and correlation study of the blazar Ton 599, which was observed first time in flaring state at the end of 2017. Data from \textit{Fermi}-LAT, Swift-XRT/UVOT, Steward Observatory,…
We present $\gamma$-ray, X-ray, ultraviolet, optical, and near-infrared light curves of 33 $\gamma$-ray bright blazars over four years that we have been monitoring since 2008 August with multiple optical, ground-based telescopes and the…