Related papers: One-dimensional pair cascade emission in gamma-ray…
Time-dependent cascades of electron-positron pairs are thought to be the main source of plasma in pulsar magnetospheres and a primary ingredient to explain the nature of pulsar radio emission, a longstanding open problem in high-energy…
Ultra-high energy cosmic rays interacting with the radiation fields in the universe cause electromagnetic cascades resulting in a flux of extragalactic gamma rays, detectable to some 100 GeV. Recent precise measurements of the extragalactic…
The recent detections of TeV gamma-rays from compact binary systems show that relativistic outflows (jets or winds) are sites of effective acceleration of particles up to multi-TeV energies. In this paper, we discuss the conditions of…
Primary gamma rays emitted by extragalactic sources, such as blazars, will generate electromagnetic cascades in intergalactic space. These cascades proceed via electron-positron pair production and inverse Compton scattering on cosmic…
Observations of two well known binary systems (LS 5039 and LS I +61 303) with the satellite and Cherenkov telescopes revealed the broad band $\gamma$-ray spectra which seems to show two components, the first at GeV energies, showing…
Very-high-energy (VHE, E \gtrsim 100 GeV) gamma rays emitted by extragalactic sources, such as blazars, initiate electromagnetic cascades in the intergalactic medium. The cascade photons arrive at the earth with angular and temporal…
We apply an inverse Compton $e^\pm$ pair cascade model for $\gamma$-ray production in massive binary system LSI +61$^{\rm o}$ 303 assuming that electrons are accelerated already inside the inner part of the jet launched by the compact…
LS 5039 is a high-mass binary with a period of 4 days, containing a compact object and an O star, one of the few high-mass binaries detected in gamma-rays. Our Chandra ACIS observation of LS 5039 provided a high-significance (~10sigma)…
High-mass gamma-ray binaries consist of a presumptive pulsar in orbit with a massive star. The intense outflows from the star can absorb radio emission from the pulsar, making the detection of pulsation difficult. In this work, we present…
We investigated a wealth of X-ray and gamma-ray spectral energy distribution (SED) and multi-band light curve (LC) data of the gamma-ray binary HESS J0632+057 using a phenomenological intrabinary shock (IBS) model. Our baseline model…
Binary pulsar systems emit potentially detectable components of gamma ray emission due to Comptonization of the optical radiation of the companion star by relativistic electrons of the pulsar wind, both before and after termination of the…
The microquasar LS 5039 has recently been detected as a source of very high energy (VHE) $\gamma$-rays. This detection, that confirms the previously proposed association of LS 5039 with the EGRET source 3EG~J1824$-$1514, makes of LS 5039 a…
PSR B1259-63/LS 2883 is a gamma-ray binary system consisting of a pulsar in an eccentric orbit around a bright Oe stellar-type companion star that features a dense circumstellar disc. The high- and very-high-energy (HE, VHE) gamma-ray…
We develop a model for a possible origin of hard very high energy spectra from a distant blazar. In the model, both the primary photons produced in the source and secondary photons produced outside the source contribute to the observed high…
The observed TeV light curve from the $\gamma$-ray binary PSR B1259-63/LS 2883 shows a decrease in the flux at periastron which has not been fully explained by emission mechanisms alone. This observed decrease can, however, be explained by…
We report the first detection of gamma-ray emission up to ultra-high-energy (UHE; $>$100 TeV) emission from the prototypical gamma-ray binary system LS I +61 303 using data from the Large High Altitude Air Shower Observatory (LHAASO). It is…
LS 5039 is the only X-ray binary persistently detected at TeV energies by the Cherenkov HESS telescope. It is moreover a gamma-ray emitter in the GeV and possibly MeV energy ranges. To understand important aspects of jet physics, like the…
X-ray binaries are composed of a normal star in orbit around a neutron star or stellar-mass black hole. Radio and X-ray observations have led to the presumption that some X-ray binaries called microquasars behave as scaled down active…
Very High Energy (VHE) gamma-rays in pulsars, and their surrounding halos, are interpreted to originate from the leptonic channel, electromagnetic interactions through electron inverse Compton (IC) scattering. In the hadronic scenario,…
Dark matter annihilation and other processes may precipitate a flux of diffuse ultra-high energy $\gamma$-rays. These $\gamma$-rays may be observable in present day experiments which observe diffuse fluxes at the GeV scale. Yet the universe…