Related papers: Synchrotron vs Compton Interpretations for Extende…
We discuss how the interaction between the electrons in a relativistic jet and the Cosmic Microwave Background (CMB) affects the observable properties of radio-loud AGN at early epochs. At high z the magnetic energy density in the radio…
The flat spectrum radio quasars (FSRQs) are a sub-class of blazars characterised by prominent optical emission lines and a collimated large-scale jet along the observer line of sight. An X-ray spectral flattening has been reported in FSRQs…
Chandra X-ray observations of the high redshift (z =1.532) radio-loud quasar 3C270.1 in 2008 February show the nucleus to have a power-law spectrum, Gamma = 1.66 +/- 0.08, typical of a radio-loud quasar, and a marginally-detected Fe Kalpha…
The preliminary detection of the Galactic Center black hole Sgr A* in X-rays by the Chandra mission, as well as recent mm-VLBI measurements, impose strict constraints on this source. Using a relativistic jet model for Sgr A*, we calculate…
The reason for the difference in the composite X-ray spectrum between radio-loud quasars (RLQs) and radio-quiet quasars (RQQs) is still unclear. To study this difference, we built a new composite X-ray spectrum of RLQs by using Chandra…
Context: It has been proposed that the origin of the very high-energy photons emitted from high-mass X-ray binaries with jet-like features, so-called microquasars (MQs), is related to hadronic interactions between relativistic protons in…
During the course of an investigation on the interaction of the radio galaxy 3C129 and its ambient cluster gas, we found excess X-ray emission aligned with the northern radio jet. The emission extends from the weak X-ray core of the host…
A model to explain variable gamma-ray sources with high-mass microblazars is described. Inverse Compton interactions between the jet of a microquasar and the UV-photon field of the stellar companion can produce high-energy gamma-rays. The…
We propose the synchrotron self-Compton (SSC) scenario coupled with filamentary jet model, to reproduce the very high energy $\gamma$-ray emissions from Cen A. With reference to self-similarity of knot-like features in the jet, we assume…
If X-rays observed from any extragalactic radio jets are due to inverse Compton scattering on the cosmic microwave background (CMB) radiation, then such a source will be detectable with the same surface brightness anywhere in the more…
We study the effect of variable jet bulk Lorentz factors, i.e., either jet acceleration or deceleration, on partially synchrotron self-absorbed radio spectra from cores of radio-loud active galactic nuclei and black-hole binaries in the…
The origin of spectral curvature at energies $E\simeq 10$ keV in ultraluminous X-ray sources is not well understood. In this paper, we propose a novel mechanism based on synchrotron radiation to explain this cutoff. We show that…
The non-thermal spectra of blazars, observed from radio to GeV/TeV gamma-rays, reveal two pronounced components, both produced by radiation by energetic particles. One peaks in the IR - to soft X-ray band, radiating via the synchrotron…
We propose a jet model for the low/hard state of Galactic black-hole X-ray sources that can explain the energy spectra from radio to X-rays. The model assumes that i) there is a magnetic field along the axis of the jet; ii) the electron…
We present the first high resolution X-ray image of the jet in M 87 using the Chandra X-ray Observatory. There is clear structure in the jet and almost all of the optically bright knots are detected individually. The unresolved core is the…
Shocks arising in galaxy mergers could accelerate cosmic-ray (CR) ions to TeV-PeV energies. While propagating in the intergalactic medium, these CRs can produce high-energy neutrinos, electron-positron pairs and gamma-rays. In the presence…
Magnetars are a subclass of neutron stars with ultra-strong surface magnetic fields. Some magnetars exhibit persistent hard X-ray emission, characterized by power-law tails with photon indices around 1--1.5, extending from ${\sim}$10 keV to…
A number of recent lines of evidence point towards the presence of hot, out-flowing plasma from the central regions of compact Galactic and extragalactic X-ray sources. Additionally, it has long been noted that many of these sources exhibit…
There is an increasing number of observational evidence that very high energy gamma-rays in radio-loud active galactic nuclei are produced in the direct vicinity of a supermassive black hole (SMBH), close to the base of a relativistic jet.…
Most active galactic nuclei at the center of the nearby galaxies have super-massive black holes accreting at sub-Eddington rates through hot accretion flows or radiatively inefficient accretion flows, which efficiently produce jets. The…