相关论文: Structured jets in TeV BL Lac objects and radiogal…
TeV emission from blazars can be used to probe the intergalactic magnetic fields and measure their intensity, coherence length, and helicity. Intergalactic magnetic fields deflect the electron-positron pairs produced by very-high-energy…
Electrons at relativistic speeds, diffusing in magnetic fields, cause copious emission at radio frequencies in both clusters of galaxies and radio galaxies, through the non-thermal radiation emission called synchrotron. However, the total…
Distant BL Lacertae objects emit $\gamma$ rays which interact with the extragalactic background light (EBL), creating electron-positron pairs, and reducing the flux measured by ground-based imaging atmospheric Cherenkov telescopes (IACTs)…
BL Lac objects can be extreme in two ways: with their synchrotron emission, peaking beyond 1 keV in their spectral energy distribution, or with their gamma-ray emission, peaking at multi-TeV energies up to and beyond 10-20 TeV, like 1ES…
Ap Lib is one of the rare Low Synchrotron Peaked blazars detected so far at TeV energies. This type of source is not properly modelled by standard one-zone leptonic Synchrotron-self-Compton (SSC) emission scenarios. The aim of this paper is…
The gamma-ray emission detected from several microquasars can be produced by relativistic electrons emitting through inverse Compton scattering. In particular, the GeV emission detected from Cygnus X-3, and its orbital phase dependence,…
We study mechanisms of multi-wavelength emissions (X-ray, GeV and TeV gamma-rays) from the gamma-ray binary LS~5039. This paper is composed of two parts. In the first part, we report on results of observational analysis using four year data…
Both observational evidence and theoretical considerations from MHD simulations of jets suggest that the relativistic jets of active galactic nuclei (AGN) are radially stratified, with a fast inner spine surrounded by a slower-moving outer…
Blazars, a subclass of radio-loud active galactic nuclei with relativistic jets aligned close to our line of sight, emit highly variable non-thermal radiation across the electromagnetic spectrum. The physical origin of their emission and…
Context: We present the results of a set of observations of nine TeV detected BL Lac objects performed by the XRT and UVOT detectors on board the Swift satellite between March and December 2005. Aims: We are mainly interested in measuring…
The components of blazar jets that emit radiation span a factor of $10^{10}$ in scale. The spatial structure of these emitting regions depends on the observed energy. Photons emitted at different sites cross the lens plane at different…
The VERITAS Collaboration recently reported the detection of very-high-energy (VHE) gamma-ray emission from the prototypical radio quasar 3C273. The temporal and the spectral properties of this component do not appear compatible with the…
Radio galaxies are the only non-blazar extragalactic objects detected in the VHE (E >100 GeV) band. These objects enable the investigation of the main substructures of the AGN, in particular the core, the jet and its interaction with the…
We discuss some phenomenological aspects of $\gamma$-ray emitting jets. In particular, we present calculations of the $\gamma$-sphere and $\pi$-sphere for various target photon fields, and employ them to demonstrate how $\gamma$-ray…
Recent radio observations support a picture for star formation where there is accretion of matter onto a central protostar with the ejection of molecular outflows that can affect the surrounding medium. The impact of a supersonic outflow on…
Thanks to Hubble and Chandra telescopes, some of the large scale jets in extragalactic radio sources are now being observed at optical and X-ray frequencies. For the FR I objects the synchrotron nature of this emission is surely…
In the last few years the Fermi-LAT instrument has detected GeV gamma-ray emission from several novae. Such GeV emission can be interpreted in terms of inverse Compton emission from electrons accelerated in the shock or in terms of emission…
The recent detection of TeV gamma-radiation from the direction of the Galactic Center within several arc-minutes around Sgr A* is the first model-independent evidence of existence of high energy particle accelerator(s) in the central 10 pc…
We investigate the delayed, secondary GeV-TeV emission of gamma-ray bursts and its potential to probe the nature of intergalactic magnetic fields. Geometrical effects are properly taken into account for the time delay between primary high…
Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and Galactic microquasar systems usually have power-law emission spectra. Recent…