Related papers: Leptonic and Hadronic Models for the Extra Compone…
The study of the high-energy (MeV-GeV) part of GRBs spectrum can play a crucial role in investigating the physics of the prompt emission, but it is often hampered by low statistic and the paucity of GeV observations. In this work, we…
Strong X-ray emission from large scale jets of radio loud quasars still remains an open problem. Models based on inverse Compton scattering off CMB photons by relativistically beamed jets have recently been ruled out, since Fermi LAT…
The origin of Galactic Cosmic Rays (CRs) and the possibility of Supernova Remnants (SNRs) being potential CR accelerators is still an open debate. The charged CRs can be detected indirectly by the {\gamma}-ray observatories through the…
The Fermi-LAT \gamma-ray data have been used to study the morphological and spectral features of the so-called GeV excess - a diffuse radiation component recently discovered towards the Galactic centre. We used the likelihood method to…
We present a general self-consistent lepto/hadronic jet model for the non-thermal electromagnetic emission of microquasars. The model is applied to the low-mass microquasar (LMMQ) GX 339-4 and predicts its high-energy features. We assume…
HESS J1534-571 is a very high energy gamma-ray source that was discovered by the H.E.S.S. observatory and reported as one of several new sources with a shell-like morphology at TeV energies, matching in size and location with the supernova…
The high energy GeV emission of gamma-ray bursts (GRBs), detected by \emph{Fermi}/LAT, has a significantly different morphology compared to the lower energy MeV emission, detected by \emph{Fermi}/GBM. Though the late time GeV emission is…
Blazar emission models are usually divided into two big families, leptonic and hadronic, according to the particles which are responsible for the gamma-ray component of their spectral energy distributions. Even though leptonic models have…
Context. In the last five years the Fermi Large Area Telescope (LAT) instrument detected GeV {\gamma}-ray emission from five novae. The GeV emission can be interpreted in terms of an inverse Compton process of electrons accelerated in a…
We analyze 10 years of Fermi-LAT data towards the SS433/W50 region. With the latest source catalog and diffuse background models, the gamma-ray excess from SS433/W50 is detected with a significance of 6{\sigma} in the photon energy range of…
Extreme blazars have exceptionally hard intrinsic X-ray/TeV spectra and extreme peak energies in their spectral energy distribution (SED). Observational evidence suggests that the non-thermal emission from extreme blazars is typically…
We present a leptonic model on the external shock framework to describe the long- and short- lasting GeV component of some GRBs. This model was already applied successfully to GRB 090926A, and we extend it to describe the high-energy…
A 5.5-year Fermi LAT gamma-ray observation shows significant extended emission at the position of the supernova remnant HB9 (G160.9+2.6). The significance of the detection above the background for photon energies above 0.2 GeV is…
Recently, Fermi-LAT detected GeV emission during the X-ray flaring activity in GRB 100728A. We study various scenarios for its origin. The hard spectrum of the GeV emission favors the external inverse-Compton origin in which X-ray flare…
We report our independent GeV gamma-ray study of the young shell-type supernova remnant (SNR) Kes 73 which harbors a central magnetar, and CO-line millimeter observations toward the SNR. Using 7.6 years of Fermi-LAT observation data, we…
The dominant component of the (100 MeV - 50 GeV) GRB emission detected by LAT starts with a delay relative to the prompt soft (sub-MeV) gamma-rays and lasts long after the soft component fades. This has lead to the intriguing suggestion…
In our model, the acceleration and propagation of particles from the Bohm-like diffusion region inside the SNR to the Galactic diffusion region outside the SNR are described through nonlinear diffusive shock acceleration (NLDSA). The main…
We report the detection of GeV $\gamma$-ray emission from the very-high-energy (VHE) $\gamma$-ray source VER J2227+608 associated with the "tail" region of SNR G106.3+2.7. The GeV $\gamma$-ray emission is extended and spatially coincident…
This work explores whether hadronic processes could be responsible for the high-energy emission seen in quasars identified by the Large Area Telescope (LAT) instrument aboard the Fermi satellite. In contrast to purely leptonic models, this…
The emission of the so-called extreme BL Lacs poses challenges to the particle acceleration models. The hardness of their spectrum, $\lesssim 2$, in the high-energy band demands unusual parameters using the standard one-zone synchrotron…