搜索结果: 1-15 共查到“知识库 天体物理学 high energy”相关记录28条 . 查询时间(0.086 秒)
Testing the isotropy of high energy cosmic rays using spherical needlets
Testing isotropy high energy cosmic rays using spherical
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2011/10/14
For many decades, ultra-high energy charged particles have been a puzzle for particle physicists and astrophysicists. Nor the sites of production, nor the mechanism responsible for the generation of t...
Blazars as Ultra-High-Energy Cosmic-Ray Sources: Implications for TeV Gamma-Ray Observations
Ultra-High-Energy Cosmic-Ray Sources Implications TeV Gamma-Ray Observations
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2011/10/20
Spectral fitting of correlated multiwavelength data of BL Lac objects and Fanaroff-Riley I radio galaxies gives the mean comoving magnetic field strength B', the bulk outflow Doppler factor Gamma, and...
High Energy Neutrinos from Gamma Ray Bursts
High Energy Neutrinos Gamma Ray Bursts
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2011/10/13
In the internal shock model of gamma ray bursts ultrahigh energy pions, kaons and neutrons are likely to be produced in the interactions of shock accelerated relativistic protons with low energy photo...
Constraints on the origin of ultra-high-energy cosmic rays from cosmogenic neutrinos and photons
Astroparticle physics Acceleration of particles Abundances Neutrinos Gamma-rays Relativistic processes
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2011/10/11
We study the production of cosmogenic neutrinos and photons during the extragalactic propagation of ultra-high-energy cosmic rays (UHECRs). For a wide range of models in cosmological evolution of sour...
Chandra High Energy Grating Observations of the Fe Ka Line Core in Type 2 Seyfert Galaxies: A Comparison with Type 1 Nuclei
galaxies active – line:profile – X-rays:galaxies
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2011/8/24
We present a study of the core of the Fe Ka emission line at ~6.4 keV in a sample of type II Seyfert galaxies observed by the Chandra High Energy Grating (HEG). The sample consists of 29 observations ...
Chandra High Energy Grating Observations of the Fe Ka Line Core in Type 2 Seyfert Galaxies: A Comparison with Type 1 Nuclei
Grating Observations Seyfert Galaxies Comparison
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2011/9/26
We present a study of the core of the Fe Ka emission line at ~6.4 keV in a sample of type II Seyfert galaxies observed by the Chandra High Energy Grating (HEG). The sample consists of 29 observations ...
Atmospheric lepton fluxes at very high energy
Atmospheric lepton fluxes energy
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2011/1/10
The observation of astrophysical neutrinos requires a detailed understanding of the atmospheric neutrino background. Since neutrinos are produced in meson decays together with a charged lepton, import...
A decay of the ultra-high-energy neutrino $\nu_e \to e^- W^+$ in a magnetic field and its influence on the shape of the neutrino spectrum
the ultra-high-energy neutrino the neutrino spectrum
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2011/1/13
The width of the neutrino decay into the electron and $W$ boson in a strong external magnetic field is obtained from the imaginary part of the neutrino self-energy. This result corrects the formulae ...
Optical Spectral Variability of the Very-High-Energy Gamma-Ray Blazar 1ES 1011+496
Optical Spectral Variability the Very-High-Energy Gamma-Ray Blazar 1ES 1011+496
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2011/1/11
We present results of five years of optical (UBVRI) observations of the very-high-energy gamma-ray blazar 1ES 1011+496 at the MDM Observatory. We calibrated UBVRI magnitudes of five comparison stars i...
Long-term lightcurves from combined unified very high energy $\gamma$-ray data
Long-term lightcurves combined unified
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2011/1/11
Very high-energy (VHE, E\,$>$\,100\,GeV) $\gamma$-ray data are a valuable input for multi-wavelength and multi-messenger (e.g. combination with neutrino data) studies. We aim at the conservation and h...
A new limit on the Ultra-High-Energy Cosmic-Ray flux with the Westerbork Synthesis Radio Telescope
the Ultra-High-Energy Cosmic-Ray flux the Westerbork Synthesis Radio Telescope
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2011/1/13
A particle cascade (shower) in a dielectric, for example as initiated by an ultra-high energy cosmic ray, will have an excess of electrons which will emit coherent \v{C}erenkov radiation, known as the...
Discriminating the source of high-energy positrons with AMS-02
high-energy positrons AMS-02
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2011/1/11
We study the prospects for discriminating between the dark matter (DM) and pulsar origin of the PAMELA positron excess with the Alpha Magnetic Spectrometer AMS-02. We simulate the response of AMS-02 t...
The MIDAS experiment: A prototype for the microwave emission of Ultra-High Energy Cosmic Rays
The MIDAS experimen the microwave emission Ultra-High Energy Cosmic Rays
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2011/1/11
Recent measurements suggest that extensive air showers initiated by ultra-high energy cosmic rays (UHECR) emit signals in the microwave band of the electromagnetic spectrum caused by the collisions of...
The metallicity of gamma-ray burst environments from high energy observations
Gamma-ray burst general – Gamma-ray burst individual GRB050904 – early Universe – dark ages
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2010/11/10
Context. Gamma-ray bursts (GRBs) and their early afterglows ionise their circumburst material. Only high-energy spectroscopy therefore, allows examination of the matter close to the burst itself. Soft...
On the Implications of Late Internal Dissipation for Shallow-Decay Afterglow Emission and Associated High-Energy Gamma-Ray Signals
gamma-rays burst general— gamma rays theory— radiation mechanisms non-thermal
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2010/11/10
The origin of the shallow-decay emission during early X-ray afterglows has been an open issue since the launch of the Swift satellite. One of the appealing models is the late internal dissipation mode...