TeV BL Lacertae objects require extreme relativistic bulk motion in the gamma–ray emission region, but at the VLBI scale their radio knots hardly move. The same sources show evidence, in radio, of a structure made of a fast spine plus a slow layer. We propose that this structure exists even on the spatial scale of regions responsible for the gamma–ray emission. One component sees the (beamed) r...

The recently approved COBRAS/SAMBA cosmic microwave background (CMB) mission will also have a major impact on measurements of the Sunyaev-Zeldovich (SZ) effect. The frequency of three of the channels (150 GHz, 217 GHz, 353 GHz) are chosen to optimize measurements of the thermal and kinetic SZ effect mainly caused by hot gas in clusters of galaxies. Estimates of the number of detected clusters a...

Current constraints on photon velocity variability are summarized and displayed in terms of an energy dependent vacuum refraction index. It is shown that the energy-momentum balance of high energy Compton scattering is very sensitive to the outgoing photon speed. A missing energy observation in HERA Compton polarimeter data indicates that photons with 12.7 GeV energy are moving faster than ligh...

We select eight nearby AGNs which, based on previous work, appear to be Compton-thin in the line of sight. model with MYTORUS their broadband X-ray spectra from 20 individual observations $Suzaku$, accounting self-consistently for Fe K$\alpha$ emission, as well direct and scattered continuum matter finite column density solar abundance. Our configuration allows us measure global, out sight, equ...

We revisit the shocked shell model for the class of Active Galactic Nuclei known as Gigahertz Peak Spectrum sources, incorporating new observational data on the radiation brightness temperatures. We argue that in addition to free–free absorption, induced Compton scattering will also have an important effect in forming the ∼ GHz peak and in shaping the radio spectra that characterize these sourc...

The hot accretion flow (such as advection-dominated accretion flow) is usually optically thin in the radial direction, therefore the photons produced at one radius can travel for a long distance without being absorbed and heat or cool electrons at other radii via Compton scattering. This effect has been ignored in most previous works on hot accretion flows and is the focus of this paper. If the...

Abstract Blazars show extreme observational properties that are due to the beaming effect with jet being close line of sight. It was found observed luminosity is anticorrelated synchrotron peak frequency but debeamed and positively correlated. In this work, we revisit correlation for a large sample 255 blazars from fourth Fermi catalog available Doppler factors. Our analysis comes following con...

The QCD processes that give rise to scaling violations in DIS at leading order, namely QCD Compton (QCDC) and boson–gluon fusion (BGF), also give rise to distinct jets in the final state provided that the energy and momentum transfer are large enough. These processes are illustrated in Fig. 1. Both BGF and QCDC depend on αs(MZ), but the BGF process also depends directly on the gluon parton dist...

It has been recently proposed [1] to use polarization of Compton scattered γrays to improve the imaging performance of Compton telescopes. Building upon that work, we detected the aforementioned polarization in a sample of 1.836 MeV γ-rays from the LXeGRIT Compton telescope. Here we present the measurement, together with detector oriented considerations on the application of the principle to a ...