Related papers: Implications of Bulk Velocity Structures in AGN Je…
Extremely flat and inverted radio spectra as observed in galactic nuclei and BL Lac sources are still a challenge for fast particle acceleration models. Continuous acceleration by electric fields in reconnection regions can result in almost…
The broadband SEDs of blazars show two distinct components which in leptonic models are associated with synchrotron and SSC emission of highly relativistic electrons. In some sources the SSC component dominates the synchrotron peak by one…
The origin of the high-energy component in spectral energy distributions (SED) of blazars is still a bit of a mystery. While BL Lac objects can be rather successfully modelled within the one-zone synchrotron self-Compton (SSC) scenario, the…
Astrophysical jets exist from the stellar scale up to AGN, and seem to share common features particularly in the radio. But while AGN jets are known to emit X-rays, the situation for XRB jets is not so clear. Radio jets have been resolved…
In this presentation, we report the results of intraday variability in the optical (BVRI bands) and hard X-ray band (3-79 keV) in a number of blazars. In the optical microvariability studies of the blazars S5 0716+714 and BL Lac, we…
The 2017 observing campaign of the Event Horizon Telescope (EHT) delivered the first very long baseline interferometry (VLBI) images at the observing frequency of 230 GHz, leading to a number of unique studies on black holes and…
The blue-shifted broad absorption lines (BAL) or troughs are observed in Active Galactic Nuclei (AGNs) when our line of sight is intercepted by a high speed outflow (wind), likely originating in the accretion disc. The outflow or wind can…
This paper is a brief review of the processes responsible for X-ray emission from radio jets, lobes and hot spots. Possible photons in inverse Compton scattering models include the radio synchrotron radiation itself (i.e. synchrotron…
Context: Few Active Galactic Nuclei (AGN) reveal a double sided jet system. However, these are crucial to understand basic physical properties of extragalactic jets. Aims: We address the questions whether jets in AGN are symmetric in…
Compact Symmetric Objects (CSOs) are a distinct category of jetted active galactic nuclei (AGN) whose optical variability characteristics have not been well investigated. We present here the results of our investigation on the optical flux…
The physics-determined broadband spectral energy distributions (SEDs) of blazars have been widely used to study the property during their flaring/outburst states, while the non-flaring state takes up most of their lifetime and the general…
Active galactic nucleus (AGN) powered jets can accelerate cosmic ray electrons, leading to the observed radio synchrotron emission. To simulate this emission, jet dynamics in galaxy clusters must be coupled to electron spectral modelling.…
We present the first collective evidence that Fermi-detected jets of high kinetic power (L_kin) are dominated by inverse Compton emission from upscattered external photons. Using a sample with a broad range in orientation angle, including…
Relativistic jets are a common feature of radio loud active galactic nuclei. Multifrequency observations are a unique tool to constrain their physics. We report on a detailed study of the properties of the jet of the nearby BL Lac object…
We interpret the linear polarization structures observed in extragalactic radio sources, even those oriented at oblique angles to the jet flows, to be due to oblique, relativistic shock fronts in the emitting regions. Many sources exhibit…
Flat radio spectra of compact jets launched by both supermassive and stellar-mass black holes are explained by an interplay of self-absorbed synchrotron emission up to some distance along the jet and optically thin synchrotron at larger…
We consider the emission processes in the large-scale jets of powerful quasars based on the results obtained with the VLA, Spitzer, Hubble, and Chandra. We show that two well-known jets, 3C 273 and PKS 1136-135, have two distinct spectral…
Recent observations in X-rays and gamma-rays of nearby FRI radio galaxies have raised the question of the origin of the emission detected in the termination structures of their jets. The study of these structures can give information on the…
Relativistic jets of radio loud active galactic nuclei (AGN) produce highly directed, intense beams of radiation. A fraction of this beamed radiation scatters on the thermal plasma generally surrounding an AGN. The morphology of the…
We present a study of the flux and spectral variability of the two broad-line radio galaxies (BLRGs) 3C 390.3 and 3C 120, observed almost daily with RXTE for nearly two months each in 1996 and 1997, respectively. Our original motivation for…