Related papers: Gamma Rays from SN1987A due to Pseudoscalar Conver…
Kes 41 is among the Galactic supernova remnants (SNRs) proposed to be physically linked to $\gamma$-ray emission at GeV energies. Although not conclusively, the nature of the $\gamma$-ray photons has been explained by means of hadronic…
Very high energy (> 100 GeV) gamma-ray emission has been detected for the first time from the composite supernova remnant G0.9+0.1 using the H.E.S.S. instrument. The source is detected with a significance of 13 sigma, and a photon flux…
Recent results, the present status and the perspectives of high energy gamma-ray astronomy are described. Since the satellite observations by the Compton Gamma Ray Observatory and its precursor missions have been reviewed extensively,…
We report on the discovery of a shell-type supernova remnant in the southern sky. It is a large (8*8), low-brightness source with a nonthermal radio spectrum, which requires background filtering to isolate it from the diffuse background…
The acceleration times of the highest-energy particles which emit gamma-rays in young and middle-age SNRs are comparable with SNR age. If the number of particles starting acceleration was varying during early times after the supernova…
We present the first individual and stacking systematic search for $\gamma$-ray emission in the GeV band with the {\it Fermi} Large Area Telescope (LAT), in the directions of 45 super-luminous supernovae (SLSNe). No excess of \gam rays from…
Gamma-ray Astronomy studies cosmic accelerators through their electromagnetic radiation in the energy range between ~100 MeV and ~100 TeV. The present most sensitive observations in this energy band are performed, from space, by the Large…
At least three pulsars in supernova remnants were detected at E > 100 MeV by EGRET on the Compton Gamma Ray Observatory. Efforts to search for additional pulsars in the EGRET data have been unsuccessful due to limited statistics. An example…
We analyze the results of recent measurements of Galactic cosmic ray (GCRs) energy spectra and the spectra of nonthermal emission from supernova remnants (SNRs) in order to determine their consistency with GCR origin in SNRs. It is shown…
Within a multicomponent dark matter scenario, novel gamma-ray signals may arise from the decay of the heavier dark matter component into the lighter. For a scalar dark sector of this kind, the decay $\phi_2\rightarrow\phi_1 \gamma$ is…
We consider a magnetized neutron star with accretion from a companion star or a gas cloud around it, as a possible source of gamma rays with energy between $100$ $MeV$ and $10^{14}-10^{16}~eV$. The flow of the accreting plasma is terminated…
The observations suggest that $\gamma$-ray bursts (GRBs) are produced by jets of relativistic cannonballs (CBs), emitted in supernova (SN) explosions. The CBs, reheated by their collision with the SN shell, emit radiation and Doppler-boost…
The diffuse galactic gamma-ray spectrum measured by the EGRET experiment \citep{Hunter:1997} are interpreted within a scenario in which cosmic rays (CRs) are injected by three different kind of sources, (i) supernovae (SN) which explode…
Superluminous supernovae (SLSNe) are a rare class of stellar explosions with luminosities ~10-100 times greater than ordinary core-collapse supernovae. One popular model to explain the enhanced optical output of hydrogen-poor (Type I) SLSNe…
We present two models for the cosmological UV background light, and calculate the opacity of GeV gamma--rays out to redshift 9. The contributors to the background include 2 possible quasar emissivities, and output from star--forming…
Measurements of high-energy photons from cosmic sources of nuclear radiation through ESA's INTEGRAL mission have advanced our knowledge: New data with high spectral resolution showed that characteristic gamma-ray lines from radioactive…
The large-scale Galactic interstellar radiation field (ISRF) is the result of stellar emission and dust re-processing of starlight. Where the energy density of the ISRF is high (e.g., the Galactic Centre), the dominant gamma-ray emission in…
Gravitational waves and electromagnetic radiations from a neutron star merger were discovered on 17 August 2017. Multiband observations of the optical transient have identified brightness and spectrum features broadly consistent with…
A new extended gamma-ray source, which was named as Source A, in the southwest of Galactic supernova remnant (SNR) G306.3$-$0.9 was detected with a significance of $\sim$13$\sigma$ at the location of R.A. (J2000) = 13$^{\rm{h}}$…
We consider the result of acceleration of heavy ions in the slot gap potential of a very young pulsar with a hot polar cap. Photodisintegration of the heavy ions in the radiation field of the polar cap and pulsar surface gives rise to a…