相关论文: Constraints on diffuse gamma-ray emission from str…
We report the discovery of high-energy (E>100 MeV) gamma-ray emission from NGC 1275, a giant elliptical galaxy lying at the center of the Perseus cluster of galaxies, based on observations made with the Large Area Telescope (LAT) of the…
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…
Massive protostars have associated bipolar outflows with velocities of hundreds of km/s. Such outflows produce strong shocks when interact with the ambient medium leading to regions of non-thermal radio emission. Under certain conditions,…
We analyze the emission in the 0.3-30 GeV energy range of Gamma-Ray Bursts detected with the Fermi Gamma-ray Space Telescope. We concentrate on bursts that were previously only detected with the Gamma-Ray Burst Monitor in the keV energy…
The solar disk is a bright source of multi-GeV gamma rays, due to the interactions of hadronic cosmic rays with the solar atmosphere. However, the underlying production mechanism is not understood, except that its efficiency must be greatly…
Steady gamma-ray emission up to at least 200 GeV has been detected from the solar disk in the Fermi-LAT data, with the brightest, hardest emission occurring during solar minimum. The likely cause is hadronic cosmic rays undergoing…
Very high energy gamma-ray data obtained by CAT and HEGRA from active galactic nucleus Mkn 501 are used to constrain the cosmic Mid-Infrared background. While the entire infrared and submillimeter spectrum shape based on models has been…
We report on the search for gamma-ray emission from 20 magnetars using 6 years of Fermi, Large Area Telescope (LAT) observations. No significant evidence for gamma-ray emission from any of the currently-known magnetars is found. We derived…
The XRISM Resolve microcalorimeter array measured the velocities of hot intracluster gas at two positions in the Coma galaxy cluster: 3'x3' squares at the center and at 6' (170 kpc) to the south. We find the line-of-sight velocity…
In order to detect the gamma-ray emission from cosmic ray (CR) interactions with the intra-cluster medium, the ground-based imaging Cherenkov telescope MAGIC conducted the deepest-to-date observational campaign targeting a galaxy cluster at…
We investigate numerically the contribution to the cosmic gamma-ray background from cosmic-rays ions and electrons accelerated at intergalactic shocks associated with cosmological structure formation. We show that the kinetic energy of…
Weak shocks in the intracluster medium may accelerate cosmic-ray protons and cosmic-ray electrons differently depending on the angle between the upstream magnetic field and the shock normal. In this work, we investigate how shock obliquity…
Fermi bubbles are giant gamma-ray structures extended north and south of the Galactic center with characteristic sizes of order of 10 kpc recently discovered by Fermi Large Area Telescope. Good correlation between radio and gamma-ray…
A shock-accelerated particle flux \propto p^-s, where p is the particle momentum, follows from simple theoretical considerations of cosmic-ray acceleration at nonrelativistic shocks followed by rigidity-dependent escape into the Galactic…
The recent discovery of the gamma-ray emission from the lobes of the closest radio galaxy Centaurus A by Fermi implies the presence of high-energy electrons at least up to gamma ~ 10^5 - 10^6. These high-energy electrons are required to…
At energies above a few TeV, no measurements of the cosmic-ray electron spectrum exist yet. By considering the similarity of air showers induced by electrons and gamma rays as seen by ground-based arrays, we use published limits on…
In the next years the FERMI gamma ray telescope and the Cherenkov telescopes will put very stringent constraints to models of gamma ray emission from galaxy clusters providing crucial information on relativistic particles in the…
Cosmology models predict that external accretion shocks form in the outer region of galaxy clusters due to supersonic gas infall from filaments and voids in the cosmic web. They are characterized by high sonic and Alfv\'enic Mach numbers,…
If supernova remnants (SNRs) are the sites of cosmic-ray acceleration, the associated nuclear interactions should result in observable fluxes of TeV gamma-rays from the nearest SNRs. Measurements of the gamma-ray flux from six nearby,…
We present the detections of 19 solar flares detected in high-energy gamma rays (above 100 MeV) with the Fermi Large Area Telescope (LAT) during its first four years of operation. Interestingly, all flares are associated with fairly fast…