Related papers: Diffuse gamma-ray emission toward the massive star…
Galaxy clusters act as reservoirs of high-energy cosmic rays (CRs). As CRs propagate through the intracluster medium, they generate diffuse $\gamma$-rays detectable by arrays such as LHAASO. These $\gamma$-rays result from proton-proton…
High energy gamma-ray emission from two nearby bright starburst galaxies, M82 and NGC 253, have recently been detected by Fermi, H.E.S.S., and VERITAS. Since starburst galaxies have a high star formation rate and plenty of dust in the…
The inner region of the Milky Way is one of the most interesting and complex regions of the gamma-ray sky. The intense interstellar emission and resolved point sources, as well as potential contributions by other sources such as unresolved…
Star-forming and starburst galaxies (SFGs and SBGs) are powerful emitters of non-thermal $\gamma$-rays and neutrinos, due to their intense phases of star-formation activity, which should confine high-energy Cosmic-Rays (CRs) inside their…
Star formation in galaxies is observed to be associated with gamma-ray emission. The detection of gamma rays from star-forming galaxies by the Fermi Large Area Telescope (LAT) has allowed the determination of a functional relationship…
Cosmic rays that escape their acceleration site interact with the ambient medium and produce gamma rays as the result of inelastic proton-proton collisions. The detection of such diffuse emission may reveal the presence of an accelerator of…
The $\gamma$-ray emission from stars is induced by the interaction of cosmic rays with stellar atmospheres and photon fields. This emission is expected to come in two components: a stellar disk emission, where $\gamma$-rays are mainly…
We analyze the gamma-ray sky at energies of 0.5 to 50 GeV using the undecimated wavelet transform on the sphere. Focusing on the inner $60^{\circ} \times 60^{\circ}$ of the sky, we identify and characterize four separate residuals beyond…
More than 90% of the Galactic gas-related gamma-ray emissivity above 1 GeV is attributed to the decay of neutral pions formed in collisions between cosmic rays and interstellar matter, with lepton-induced processes becoming increasingly…
Context: The Large Magellanic Cloud (LMC) is to date the only normal external galaxy that has been detected in high-energy gamma rays. High-energy gamma rays trace particle acceleration processes and gamma-ray observations allow the nature…
Evidence of efficient acceleration of cosmic rays in massive young stellar objects has been recently reported. Among these massive protostars, S255 NIRS 3 for which extreme flaring events associated with radio jets have been detected, is…
Massive star clusters (SCs) have been proposed as additional contributors to Galactic Cosmic rays (CRs), to overcome the limitations of supernova remnants (SNR) to reach the highest energy end of the Galactic CR spectrum. Thanks to fast…
The diffuse Galactic gamma-ray emission is produced by cosmic rays (CRs) interacting with the interstellar gas and radiation field. Measurements by the Energetic Gamma-Ray Experiment Telescope (EGRET) instrument on the Compton Gamma-Ray…
Globular clusters (GCs) are emerging as a new class of gamma-ray emitters, thanks to the data obtained from the Fermi Gamma-ray Space Telescope. By now, eight GCs are known to emit gamma-rays at energies >100~MeV. Based on the stellar…
Galaxy clusters are the most massive gravitationally bound structures in the Universe. Even if clusters are nearly virialized structures, they undergo merging processes, creating merging shocks, and suffer from feedback from galaxies and…
Cosmic rays fill up the entire volume of galaxies, providing an important source of heating and ionisation of the interstellar medium, and may play a significant role in the regulation of star formation and galactic evolution. Diffuse…
The Fermi-LAT data accumulated over 7 years of {\gamma}-ray observations, together with the high resolution gas (CO & HI) and the dust opacity maps, are used to study the emissivity of {\gamma}-rays induced by interactions of cosmic rays…
It is widely accepted that cosmic rays (CRs) up to at least PeV energies are Galactic in origin. Accelerated particles are injected into the interstellar medium where they propagate to the farthest reaches of the Milky Way, including a…
We discuss the prospects of detecting the sources of ultra-high energy (UHE) cosmic ray (CR) nuclei via their emission of cosmogenic gamma-rays in the GeV to TeV energy range. These gamma-rays result from electromagnetic cascades initiated…
We consider the thermal and non-thermal emission from the inner 200 pc of the Galaxy. The radiation from this almost star-burst-like region is ultimately driven dominantly by on-going massive star formation. We show that this region's radio…