The new distant metagalactic γ-sources 1739+522 ( z = 1.375) and 3c454.3 ( z = 0.857) are detected at energies E > 0.8 TeV with the fluxes (0.53 ± 0.10) × 10-12 cm -2 s -1 and (0.43 ± 0.13) × 10-12 cm -2 s -1, respectively. The γ-ray spectra and fluxes of known blazars Mkn 421, Mkn 501 and distant flat-spectrum radio quasars 1739+522 and 3c454.3 are presented.
An information about high-energy CR population in SNRs can be obtained from gamma-ray observation. High-energy gamma-rays are produced by electronic and hadronic CR components in the inverse Compton (IC) scattering and in the hadronic collisions leading to pion production and subsequent decay respectively. SNe of type Ib and II are more numerous in our Galaxy. According to the theoretical prediction about 20 SNRs should be visible in the TeV gamma-rays whereas only two were detected up to now by SHALON, namely Tycho's SNR and Geminga. The expected pion decay gamma-flux Fγ ∼ E −1 γ extends up to > 30T eV, whereas the IC gamma-ray flux has a cutoff above a few TeV. So, a detection of gamma-rays at energies of 10-40 TeV by SHALON is an evidence for hadron origin of the rays. An another class of objects considered as a particle accelerator in the Galaxy are Pulsar Wind Nebulae (PWN). One of them is Crab Nebula, observed through all bands of electromagnetic spectrum. Crab Nebula has an extraordinary broad spectrum, attributed to synchrotron radiation of electrons with energies from GeV to PeV. This continuous spectrum appears to terminate near 10 8 eV and photons, produced by relativistic electrons and positrons (∼ 10 15 eV) via Inverse Compton, form a new component of spectrum in GeV-TeV energy range. The spectrum of gamma rays from the Crab Nebula has been measured in the energy range 0.8 TeV to 11 TeV at the SHALON Alatoo Observatory by the atmospheric Cerenkov technique. The integral energy spectrum is well described by the single power law I(> Eγ) ∝ E −1.44±0.07 γ. An image of gamma-ray emission from Crab Nebula by SHALON telescope is presented. The VHE spectral energy distribution of the Crab Nebula is compared with the predictions of a synchrotron self-Compton emission model in energy range 0.8 TeV to 11 TeV (Hillas et al. 1998).
Few-mode interference patterns produced by a fiber optic are composed of lobes whose intensity and displacement in the fiber cross-section are dependent on external disturbances like temperature and strain. This paper presents an image processing algorithm which computes the lobes coordinates and records their trajectory with respect to time. It is then numerically and experimentally demonstrated that the trajectory length of path is proportional to the temperature integrated all along the fiber (only thermal disturbance is considered). The heating and cooling phase discrimination issue is solved by inserting a cyclically heated fiber sample in the fiber under test and by analyzing the associated trajectory impact. A frequency-domain analysis has been used for suppressing vibration-induced disturbances. A low-cost experimental trial setup and the corresponding results are showing an accuracy of 1°C.
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