Related papers: Gamma-rays from SS433: evidence for periodicity
We present a temporal and spectral analysis of the gamma-ray flux from nine of the brightest flat spectrum radio quasars (FSRQs) detected with the Fermi Large Area Telescope (LAT) during its first eight years of operation, with the aim of…
The gamma-ray emission of blazar jets shows a pronounced variability and this feature provides limits to the size and to the speed of the emitting region. We study the gamma-ray variability of bright blazars using data from the first 18…
We discuss the gamma-ray absorption in the inner region of the microquasar SS433. Our investigation includes several contributions to the opacity of this system. They result from the ambient fields generated by the primary star, possibly an…
The possible association between the microquasar LS 5039 and the EGRET source 3EG J1824-1514 suggests that microquasars could also be sources of high energy gamma-rays. In this paper, we explore, with a detailed numerical model, if this…
We investigate hadronic and leptonic scenarios for the GeV--TeV gamma-ray emission from jets of the microquasar SS 433. The emission region of the TeV photons coincides with the X-ray knots, where electrons are efficiently accelerated. On…
The detection of several radio-loud narrow-line Seyfert 1 (NLS1) galaxies by the Fermi Gamma-Ray Space Telescope hints at the existence of a rare, new class of gamma-ray emitting active galactic nuclei with low black hole masses. Like flat…
Blazars can be detected from very large distances due to their high luminosity. However, the detection of $\gamma$-ray emission of blazars beyond $z=3$ has only been confirmed for a small number of sources. Such observations probe the…
In the work we search for the $\gamma$-ray signal from M33, one of the biggest galaxies in the Local Group, by using the Pass 8 data of Fermi Large Area Telescope (LAT). No statistically significant gamma-ray emission has been detected in…
Narrow line Seyfert 1 galaxies (NLS1s) usually do not host relativistic jets and the detection of their $\gamma$-ray emissions is rarely reported. Evidences for strong relativistic beaming effect have been found in all $\gamma$-ray NLS1s to…
We investigate the contribution of the beamed jet component to the high energy emission in young and compact extragalactic radio sources, focusing for the first time on the gamma-ray band. We derive predictions on the gamma-ray luminosities…
The recent detection of gamma-ray emission from four radio-loud narrow-line Seyfert 1 galaxies suggests that the engine driving the AGN activity of these objects share some similarities with that of blazars, namely the presence of a…
We present VLBI imaging results for SS433 from the period 1995-2000. An equatorial emission region is detected and confirmed in 7 experiments at 1.6 and 5 GHz. The structure of the region changes with time on scales of weeks to months. The…
One of the most intriguing and challenging quests of current astrophysics is to understand the physical conditions and processes responsible for production of high-energy particles, and emission of \gamma-rays. A combination of…
SS433 is an X-ray binary emitting persistent relativistic double sided jets that expand into the surrounding W50 radio nebula. The SS433/W50 system is then an excellent laboratory for studying relativistic jet interaction with the…
Microquasars, X-ray binary systems that generate relativistic jets, were discovered in our Galaxy in the last decade of the XXth century. Their name indicates that they are manifestations of the same physics as quasars but on a completely…
Among thousands of extragalactic $\gamma$-ray emitters, only a handful of distant ($z >$ 3) sources are detected. Yet, they are crucial probes shedding light on the cosmic evolution of jets of active galactic nuclei and the initial phase of…
A 2.1-year periodic oscillation of the gamma-ray flux from the blazar PG 1553+113 has previously been tentatively identified in almost 7 year of data from the Fermi Large Area Telescope. After 15 years of Fermi sky-survey observations,…
We present observations of the SS 433 jets using the Chandra High Energy Transmission Grating Spectrometer with contemporaneous optical and VLBA observations. The X-ray and optical emission line regions are found to be related but not…
Almost 10 yr of $\gamma$-ray observations with the Fermi Large Area Telescope (LAT) have revealed extreme $\gamma$-ray outbursts from flat spectrum radio quasars (FSRQs), temporarily making these objects the brightest $\gamma$-ray emitters…
We report on the jet structure in SS 433 based on X-ray high resolution spectroscopy with the XRISM/Resolve. The source was observed over 5 days covering both inside and outside an eclipse of the compact object by the companion star.…