Ashot Chilingarian | Yerevan Physics Institute (original) (raw)
Address: Yerevan, Yerevan, Armenia
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Measured intensities of the galactic cosmic rays are described rather satisfactory till energy 10... more Measured intensities of the galactic cosmic rays are described rather satisfactory till energy 1017 eV by the acceleration of protons and nuclei in supernovae explosion blasts in presence of strong magnetic fields. At 1015eV this mechanism faded producing the first "proton" knee; at 1017eV, the iron nuclei also cannot gain additional energy crossing SNR generated shock The energy domain 1017eV 1018eV is an enigmatic region where may be mysterious extragalactic CRs, presumably produced in Active Galactic Nuclei are mixing with fading galactic iron flux. There are different scenarios of mixing of both components and absolutely not enough experimental evidence for comparisons. KASCADE, MAKET-ANI and HighRes data seem to suggest a "bump" after 1017 eV, although error bars are too large for the physical inference. AKENO data suggested rather smooth transition. This important question of transition from galactic to extragalactic component can only be solved by measurin...
Eos, Transactions American Geophysical Union, 2014
Nuclear Physics B - Proceedings Supplements, 2006
Nuclear Physics B - Proceedings Supplements, 2006
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1997
A composition analysis of KASCADE air shower data is performed by means of unfolding the two-dime... more A composition analysis of KASCADE air shower data is performed by means of unfolding the two-dimensional electron-muon number spectrum in energy spectra of 5 elemental groups. The results of the analysis are based on a vast number of Monte Carlo simulations with the two different high-energy hadronic interaction models QGSJet and SIBYLL. For both models the light elemental groups show a distinctive knee feature, causing the knee in the all particle spectrum at around 4 PeV, whereas heavy primaries do not. The relative abundancies of the elemental groups show a large model dependence. Moreover, the description of the data by the simulations shows to be imperfect and sensitive to the characteristics of the interaction model used.
The Astrophysical Journal, 2006
The Astrophysical Journal, 2004
The Astrophysical Journal, 2008
The Astrophysical Journal, 2006
The Astrophysical Journal, 2007
The Astrophysical Journal, 2007
The Astrophysical Journal, 2008
The Astrophysical Journal, 2003
Science, 2008
The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has det... more The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar Radio Source (in short: radio quasar) 3C 279, at a distance of more than 5 billion light-years (a redshift of 0.536). No quasar has been observed previously in very-high-energy gamma radiation, and this is also the most distant object detected emitting gamma rays above 50 gigaelectron volts. Because high-energy gamma rays may be stopped by interacting with the diffuse background light in the universe, the observations by MAGIC imply a low amount for such light, consistent with that known from galaxy counts.
Nuclear Physics B - Proceedings Supplements, 1997
Nuclear Physics B - Proceedings Supplements, 2003
Measured intensities of the galactic cosmic rays are described rather satisfactory till energy 10... more Measured intensities of the galactic cosmic rays are described rather satisfactory till energy 1017 eV by the acceleration of protons and nuclei in supernovae explosion blasts in presence of strong magnetic fields. At 1015eV this mechanism faded producing the first "proton" knee; at 1017eV, the iron nuclei also cannot gain additional energy crossing SNR generated shock The energy domain 1017eV 1018eV is an enigmatic region where may be mysterious extragalactic CRs, presumably produced in Active Galactic Nuclei are mixing with fading galactic iron flux. There are different scenarios of mixing of both components and absolutely not enough experimental evidence for comparisons. KASCADE, MAKET-ANI and HighRes data seem to suggest a "bump" after 1017 eV, although error bars are too large for the physical inference. AKENO data suggested rather smooth transition. This important question of transition from galactic to extragalactic component can only be solved by measurin...
Eos, Transactions American Geophysical Union, 2014
Nuclear Physics B - Proceedings Supplements, 2006
Nuclear Physics B - Proceedings Supplements, 2006
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1997
A composition analysis of KASCADE air shower data is performed by means of unfolding the two-dime... more A composition analysis of KASCADE air shower data is performed by means of unfolding the two-dimensional electron-muon number spectrum in energy spectra of 5 elemental groups. The results of the analysis are based on a vast number of Monte Carlo simulations with the two different high-energy hadronic interaction models QGSJet and SIBYLL. For both models the light elemental groups show a distinctive knee feature, causing the knee in the all particle spectrum at around 4 PeV, whereas heavy primaries do not. The relative abundancies of the elemental groups show a large model dependence. Moreover, the description of the data by the simulations shows to be imperfect and sensitive to the characteristics of the interaction model used.
The Astrophysical Journal, 2006
The Astrophysical Journal, 2004
The Astrophysical Journal, 2008
The Astrophysical Journal, 2006
The Astrophysical Journal, 2007
The Astrophysical Journal, 2007
The Astrophysical Journal, 2008
The Astrophysical Journal, 2003
Science, 2008
The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has det... more The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar Radio Source (in short: radio quasar) 3C 279, at a distance of more than 5 billion light-years (a redshift of 0.536). No quasar has been observed previously in very-high-energy gamma radiation, and this is also the most distant object detected emitting gamma rays above 50 gigaelectron volts. Because high-energy gamma rays may be stopped by interacting with the diffuse background light in the universe, the observations by MAGIC imply a low amount for such light, consistent with that known from galaxy counts.
Nuclear Physics B - Proceedings Supplements, 1997
Nuclear Physics B - Proceedings Supplements, 2003