Related papers: A Physical Model for the Revised Blazar Sequence
We present an analysis of the cross-correlation between optical brightness and polarization degree in different types of blazars. The aim is to identify objects with simultaneous and consistent changes in characteristics and to determine if…
Historically, the blazar population has been poorly understood at low frequencies because survey sensitivity and angular resolution limitations have made it difficult to identify megahertz counterparts. We used the LOFAR Two-Metre Sky…
At energies ~>2 keV, active galactic nuclei (AGN) are the source of the cosmic X-ray background (CXB). For AGN population synthesis models to replicate the peak region of the CXB (~30 keV), a highly obscured and therefore nearly invisible…
We present a numerical code, written in C, which can be used to simulate or to analyze the emission of Blazars over the entire electromagnetic spectrum. Our code can reproduce the following features: synchrotron emission, inverse Compton…
First results are presented from kinetic numerical simulations of relativistic collisionless magnetic reconnection in pair plasma that include radiation reaction from both synchrotron and inverse Compton (IC) processes, motivated by…
Active galactic nuclei (AGN) are some of the brightest and most variable objects in the Universe. Those with relativistic jets observed at small viewing angles are blazars. Due to Doppler boosting, blazars exhibit extreme stochastic…
Motivated by recent reports of strongly correlated radio and X-ray variability in 3C279 (Grandi, etal 1995), we have computed the relative amplitudes of variations in the synchrotron flux at $\nu$ and the self-Compton X-ray flux at 1 keV…
The spectral energy distribution of blazars around the synchrotron peak can be well described by the log-parabolic model that has three parameters: peak energy ($E_\textrm{p}$), peak luminosity ($L_\textrm{p}$) and the curvature parameter…
Multi-Messenger observations and theory of astrophysical objects is fast becoming a critical research area in the astrophysics scientific community. In particular, point-like objects like that of BL Lac, flat spectrum radio quasars (FSRQ),…
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…
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 detailed temporal and spectral study of the blazar 3C\,279 using multi-wavelength observations from Swift-XRT, Swift-UVOT and Fermi-LAT during a flare in 2018 January. The temporal analysis of $\gamma$-ray light curve indicates…
The eponymous BL Lac object BL Lacertae is one of the most well-monitored active galactic nuclei, frequently observed from radio to gamma rays. Its relatively soft $\gamma$-ray spectrum peaks near 500~MeV, and since 2020 it has undergone an…
We present a comprehensive temporal and spectral analysis of a few blazars using multi-wavelength observations. Rapid flux variations are quantified via the doubling/halving timescale method, revealing the shortest variability timescales of…
Fermi has provided the largest sample of gamma-ray selected blazars to date. In this work we use a uniformly selected set of 211 BL Lacertae (BL Lac) objects detected by it Fermi during its first year of operation. We have obtained redshift…
We have been using the 0.76-m Katzman Automatic Imaging Telescope (KAIT) at Lick Observatory to optically monitor a sample of 157 blazars that are bright in gamma rays, being detected with high significance ($\ge 10\sigma$) in one year by…
Jet models for the high-energy emission of Galactic X-ray binary sources have regained significant interest with detailed spectral and timing studies of the X-ray emission from microquasars, the recent detection by the HESS collaboration of…
The RoboPol instrument and the relevant program was developed in order to conduct a systematic study of the optical polarisation variability of blazars. Driven by the discovery that long smooth rotations of the optical polarisation plane…
Blazars are known to emit a broad band emission from radio to gamma-rays with rapid time variations, particularly, in X- and gamma-rays. Synchrotron radiation and inverse Compton scattering are thought to play an important role in emission…
The external Compton (EC) model is used to study the high energy emission of some blazars, in which the external photon field is considered to dominate inverse Compton radiation. We explore the properties of external photon field through…