Related papers: Gamma Rays frim the Galactic Centre
A model for high-energy (>10^14 eV) cosmic rays (HECRs) from galactic and extragalactic gamma-ray bursts (GRBs) is summarized. Relativistic outflows in GRBs are assumed to inject power-law distributions of CR protons and ions to the highest…
We report the detection of high-energy $\gamma$-ray emission in the vicinity of G172.8+1.5, which is debated as a Supernova remnant (SNR) or an ionized hydrogen (H$_{\rm{II}}$) region. Using 16-yr Pass 8 data from Fermi Large Area Telescope…
Various studies have implied the existence of a gaseous halo around the Galaxy extending out to 100 kpc. Galactic cosmic rays (CRs) that propagate to the halo, either by diffusion or by convection with the possibly existing large-scale…
Evidences of non-thermal X-ray emission and TeV gamma-rays from the supernova remnants (SNRs) has strengthened the hypothesis that primary Galactic cosmic-ray electrons are accelerated in SNRs. High energy electrons lose energy via…
Galactic diffuse continuum gamma-ray emission is intricately related to cosmic-ray physics and radio astronomy. We describe recent results from an approach which endeavours to take advantage of this. Information from cosmic-ray composition…
We report observations and analysis of infrared spectra of H3+ and CO lines in the Galactic center, within a few parsecs of the central black hole, Sgr A*. We find a cosmic ray ionization rate typically an order of magnitude higher than…
We simulate the neutrino and $\gamma$-ray emissions of the Galaxy which are originated from the hadronic scattering of cosmic rays (CR) with the interstellar medium (ISM). Rather than assuming a uniform CR density, we estimate the spatial…
The EGRET results for gamma ray intensities in and near the Galactic Plane have been analysed in some detail. Attention has been concentrated on energies above 1 GeV and the individual intensities in a $4^{\circ}$ longitude bin have been…
The origin of the X-ray emission from the central region of the Galaxy has remained a mystery, despite extensive study over the past two decades. A fundamental question is the relative contribution of the point-source and diffuse components…
Supernova remnants (SNRs) are thought to be the primary sources of Galactic Cosmic Rays (CRs). In the last few years, the wealth of gamma-ray data collected by GeV and TeV instruments has provided important information about particle…
We present a novel interpretation of the gamma-ray diffuse emission measured by H.E.S.S. in the Galactic Center (GC) region and the Galactic ridge. Our starting base is an updated analysis of PASS8 Fermi-LAT data, which allows to extend…
Recent observations of galactic cosmic rays (CR) in the 1-500 GeV energy range have revealed striking deviations from what deemed "standard." The anomalies cut across hadronic and leptonic CRs. I discuss findings that challenge physical…
It is thought that Galactic cosmic ray (CR) nuclei are gradually accelerated to high energies (up to ~300 TeV/nucleon, where 1TeV=10^12eV) in the expanding shock-waves connected with the remnants of powerful supernova explosions. However,…
Galactic cosmic rays are commonly believed to be accelerated at supernova remnants via diffusive shock acceleration. Despite the popularity of this idea, a conclusive proof for its validity is still missing. Gamma-ray astronomy provides us…
The High-Energy Stereoscopic System (HESS) has detected diffuse TeV emission correlated with the distribution of molecular gas along the Ridge at the Galactic Center. Diffuse, non-thermal emission is also seen by the Fermi large area…
Observations of very-high-energy (VHE) gamma-ray emission from supernova remnants (SNR) established them as sources of accelerated particles up to energies of 100 TeV. The dominant process - leptonic or hadronic - responsible for the VHE…
We have modelled the high-energy astrophysics of the inner 200 pc of the Galaxy with a view to explaining the diffuse, broad-band (radio continuum to TeV gamma-ray), non-thermal signal detected from this region. Our modelling pins down the…
Diffusive shock acceleration operating at expanding supernova remnant shells is by far the most popular model for the origin of galactic cosmic rays. Despite the general consensus received by this model, an unambiguous and conclusive proof…
The Galactic gamma-ray diffuse emission is currently observed in the GeV-TeV energy range with unprecedented accuracy by the Fermi satellite. Understanding this component is crucial as it provides a background to many different signals such…
GeV and TeV emission from the forward shocks of supernova remnants (SNRs) indicates that they are capable particle accelerators, making them promising sources of Galactic cosmic rays (CRs). However, it remains uncertain whether this…