Related papers: The Contribution From TeV Halos to the Isotropic G…
We study mechanisms of multi-wavelength emissions (X-ray, GeV and TeV gamma-rays) from the gamma-ray binary LS~5039. This paper is composed of two parts. In the first part, we report on results of observational analysis using four year data…
Recent results of GeV and TeV observations of gamma-rays from the Universe are briefly reviewed. Topics include observational technique, diffuse gamma-rays, pulsars, unidentified sources, plerions, supernova remnants and AGNs.
The hunt for cosmic TeV particle accelerators is prospering through Imaging Atmospheric Cerenkov Telescopes. We face challenges such as low light levels and MHz trigger rates, and the need to distinguish between particle air showers…
A few radio galaxies have been discovered to emit GeV-TeV gamma-ray emission in spite of relatively large viewing angles of their jets. We consider a scenario in which such large angle gamma-ray emission is preferentially produced by…
Pulsed emission from the Vela pulsar at energies above 3 TeV has recently been detected by the H.E.S.S. II air-Cherenkov telescope. We present a model for the broad-band spectrum of Vela from infra-red (IR) to beyond 10 TeV. Recent…
We present a detailed study of the gamma-ray emission from the direction of the star-forming region W30 based on a decade of the Fermi Large Area Telescope data in the 0.3-300 GeV photon energy range. The morphological and spectral analyses…
We observed the first unidentified TeV gamma-ray source TeV J2032+4130 with Suzaku. Owing to Suzaku's high sensitivity for detection of diffuse X-ray emission, we found two small structures in the TeV emitting region. One of them is…
We present quantitative statistical evidence for a $\gamma$-ray emission halo surrounding the Galaxy. Maps of the emission are derived. EGRET data were analyzed in a wavelet-based non-parametric hypothesis testing framework, using a model…
Globular clusters are source of gamma-ray radiation. At GeV energies, their emission is attributed to magnetospheric activity of millisecond pulsars residing in the clusters. Inverse Compton scattering of ambient photon fields on…
We have detected sub-TeV gamma-ray emission from the direction of the Galactic Center (GC) using the CANGAROO-II Imaging Atmospheric Cherenkov Telescope (IACT). We detected a statistically signicant excess at energies greater than 250GeV.…
Measurement of diffuse gamma-ray emission from the Milky Way with Imaging Atmospheric Cherenkov Telescopes (IACT) is difficult because of high level of charged cosmic ray background and small field-of-view. We show that such a measurement…
Observations of the TeV halos associated with nearby pulsars indicate that these objects inject significant fluxes of very high-energy electron-positrons pairs into the interstellar medium (ISM), thereby likely providing the dominant…
The diffuse Galactic $\gamma$-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays…
Gamma rays from TeV blazars have been detected by ground-based experiments for more than two decades. We have collected the most extensive set of archival spectra from these sources in order to constrain the processes affecting gamma-ray…
There are currently over 160 known gamma-ray pulsars. While most of them are detected only from space, at least two are now seen also from the ground. MAGIC and VERITAS have measured the gamma ray pulsed emission of the Crab pulsar up to…
TeV halos have been suggested as a common phenomenon associated with middle-aged pulsars. Based on our recent work on PSR~J0631+1036, which is the only known source positionally coincident with a hard TeV gamma-ray source and likely powers…
Observations by HAWC and Milagro have detected bright and spatially extended TeV gamma-ray sources surrounding the Geminga and Monogem pulsars. We argue that these observations, along with a substantial population of other extended TeV…
Galactic diffuse gamma-ray flux measured by the Tibet AS$\gamma$ experiment and the total Galactic gamma-ray flux measured by Large High Altitude Air Shower Observatory (LHAASO) are found to be consistent, within the statistical and…
One of the most prominent features of the $\gamma$-ray sky is the emission from our own Galaxy. The Galactic plane has been observed by Fermi-LAT in GeV and H.E.S.S. in TeV light. Fermi has modeled the Galactic emission as the sum of a…
The recent analyses of the Fermi Large Area Telescope data show an extended GeV $\gamma$-ray excess on top of the expected diffuse background in the Galactic center region, which can be explained with annihilating dark matter or a…