We report the discovery of a transient radio source 2.7 arcsec (0.1 pc projected distance) South of the Galactic Center massive black hole, Sagittarius A*. The source flared with a peak of at least 80 mJy in March 2004. The source was resolved by the Very Large Array into two components with a separation of ∼ 0.7 arcsec and characteristic sizes of ∼ 0.2 arcsec. The two components of the source ...

We demonstrate that the South Pole kilometer-scale neutrino observatory IceCube can detect multi-TeV gamma rays continuously over a large fraction of the southern sky. While not as sensitive as pointing atmospheric Cerenkov telescopes, IceCube can roughly match the sensitivity of Milagro. Also, IceCube is complementary to Milagro because it will observe, without interruption, a relatively poorl...

The history of gamma-ray astronomy began in the 1950’s when Hayakawa [1] and Morrison [2] predicted that gamma-rays would be produced via neutral pion decays generated in collisions of cosmic-rays with interstellar matter. Cherenkov observation of air showers was pioneered by Jelly [3] and Chudakov applied this technique to search for gamma-ray signals from celestial sources [4]. Since this ear...

Although gamma ray showers are muon-poor, they still produce a number of muons sufficient to make the sources observed by GeV and TeV telescopes observable also in muons. For sources with hard gamma ray spectra there is a relative ‘enhancement’ of muons from gamma ray primaries as compared to that from nucleon primaries. All shower gamma rays above the photoproduction threshold contribute to th...

It has been suggested that underwater neutrino telescopes could detect muons from gamma ray showers. ANTARES’ ability to detect high energy muons produced by TeV photons is discussed in the light of a full Monte Carlo study. It is shown that currently known sources would be hardly detectable.

We review the iid2022 workshop on statistical methods for X-ray and γ -ray astronomy high–energy astrophysics event data in astronomy, held Guntersville, AL, Nov. 15–18 2022. New faint source detection, spatial point processes, variability spectral analysis, machine learning are discussed. Ideas future developments of advanced methodology shared.