Related papers: TEV GAMMA-RAYS FROM PROTON BLAZARS
Context: Very-high-energy (VHE; E>100 GeV) {\gamma}-ray emission from blazars inevitably gives rise to electron-positron pair production through the interaction of these {\gamma}-rays with the Extragalactic Background Light (EBL). Depending…
We calculate the flux of ultra high energy photons from individual ordinary (i.e. non-superconducting) cosmic strings and compare the results with the sensitivity of current and proposed TeV and EeV telescopes. Our calculations give only…
Gamma-ray burst (GRB) engines are probed most intimately during the prompt gamma-ray luminous phase when the expanding blast wave is closest to the explosion center. Using GRBs 990123 and 940217 as guides, we briefly review observations of…
We consider theoretical models of emission of TeV photons by Cyg X-1 during a flare discovered by the MAGIC detector. We study acceleration of electrons to energies sufficient for TeV emission, and find the emission site is allowed to be…
More than a dozen blazars are known to be emitters of multi-TeV gamma rays, often with strong and rapid flaring activity. By interacting with photons of the cosmic microwave and infrared backgrounds, these gamma rays inevitably produce…
Pachmarhi Array of \v{C}erenkov Telescopes (PACT), based on wavefront sampling technique, has been used for detecting TeV gamma rays from galactic and extra-galactic $\gamma $-ray sources. The Blazar, Mkn 421 was one such extra-galactic…
Recent studies suggest that pulsars could be strong sources of TeV muon neutrinos provided positive ions are accelerated by pulsar polar caps to PeV energies. In such a situation muon neutrinos are produced through the delta resonance in…
The AMANDA neutrino telescope has recently reported the detection of high-energy neutrinos spatially and temporally coincident with the flaring of the TeV blazar 1ES 1959+650. At present, the statistical significance of this observation…
It has long been suggested that nearby pulsars within $\sim 1 \,{\rm kpc}$ are the leading candidate of the 10-500 GeV cosmic-ray positron excess measured by PAMELA and other experiments. The recent measurement of surface brightness profile…
This is the first of three plenary talks with the same title given at the 28th ICRC in Tsukuba, Japan in August, 2003. A brief description of the techniques for detecting gamma rays at TeV energies is followed by a summary of the…
Imaging Atmospheric Cherenkov Telescopes (IACTs) allow us to observe Active Galactic Nuclei (AGNs) in the 100 GeV to 20 TeV energy range with high sensitivity. The TeV gamma-ray observations of the nine blazars detected so far in this…
B2 1215+30 is a BL Lac-type blazar that was first detected at TeV energies by the MAGIC atmospheric Cherenkov telescopes, and subsequently confirmed by the VERITAS observatory with data collected between 2009 and 2012. In 2014 February 08,…
Microquasars are laboratories for the study of jets of relativistic particles produced by accretion onto a spinning black hole. Microquasars are near enough to allow detailed imaging of spatial features across the multiwavelength spectrum.…
Very high energy gamma-rays from blazars traversing cosmological distances through the metagalactic radiation field can convert into electron-positron pairs in photon-photon collisions. The converted gamma-rays initiate electromagnetic…
Blazars represent the most abundant class of high-energy extragalactic $\gamma$-ray sources. The subset of blazars known as BL Lac objects is on average closer to Earth and characterized by harder spectra at high energy than the whole…
We construct a systematic survey of extragalactic \gamma-ray sky at the energies above 100 GeV using the data of Fermi telescope. Such survey has not been previously done by the ground-based Cherenkov gamma-ray telescopes which have,…
Recently, a new method to constrain the distances of blazars with unknown redshift using combined observations in the GeV and TeV regimes has been developed. The underlying assumption is that the Very High Energy (VHE, E > 100 GeV) spectrum…
Cosmic rays represent one of the most important energy transformation processes of the universe. They bring information about the surrounding universe, our galaxy, and very probably also the extragalactic space, at least at the highest…
H1426+428 is one of blazars that are observed by $\gamma$-rays in the TeV region. Because TeV $\gamma$-rays from distant sources are subject to attenuation by the extragalactic background light (EBL) via electron-positron pair production,…
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…