238 research outputs found
A simulation of high energy cosmic ray propagation 1
High energy cosmic ray propagation of the energy region 10 to the 14.5 power - 10 to the 18th power eV is simulated in the inter steller circumstances. In conclusion, the diffusion process by turbulent magnetic fields is classified into several regions by ratio of the gyro-radius and the scale of turbulence. When the ratio becomes larger then 10 to the minus 0.5 power, the analysis with the assumption of point scattering can be applied with the mean free path E sup 2. However, when the ratio is smaller than 10 to the minus 0.5 power, we need a more complicated analysis or simulation. Assuming the turbulence scale of magnetic fields of the Galaxy is 10-30pc and the mean magnetic field strength is 3 micro gauss, the energy of cosmic ray with that gyro-radius is about 10 to the 16.5 power eV
Very Strong TeV Emission as Gamma-Ray Burst Afterglows
Gamma-ray bursts (GRBs) and following afterglows are considered to be
produced by dissipation of kinetic energy of a relativistic fireball and
radiation process is widely believed as synchrotron radiation or inverse
Compton scattering of electrons. We argue that the transfer of kinetic energy
of ejecta into electrons may be inefficient process and hence the total energy
released by a GRB event is much larger than that emitted in soft gamma-rays, by
a factor of \sim (m_p/m_e). We show that, in this case, very strong emission of
TeV gamma-rays is possible due to synchrotron radiation of protons accelerated
up to \sim 10^{21} eV, which are trapped in the magnetic field of afterglow
shock and radiate their energy on an observational time scale of \sim day. This
suggests a possibility that GRBs are most energetic in TeV range and such TeV
gamma-rays may be detectable from GRBs even at cosmological distances, i.e., z
\sim 1, by currently working ground-based telescopes. Furthermore, this model
gives a quantitative explanation for the famous long-duration GeV photons
detected from GRB940217. If TeV gamma-ray emission which is much more energetic
than GRB photons is detected, it provides a strong evidence for acceleration of
protons up to \sim 10^{21} eV.Comment: 10 pages, no figure. To appear in ApJ Letter
Core structure of EAS in 10(15) to 10(17) eV
With the use of Akeno calorimeter, the attenuation of particles in concrete is analyzed as the function of the shower size of 10 to the 5th power to 10 to the 7th power. The attenuation length does not depend much on the shower size but depends a little on the shower age. The average value is approx. 150 g/sq cm for s = 0.5 to 0.85 and approx. 40 g/sq cm for s = 0.85 to 1.15. These values and their fluctuations are consistent with the equi-intensity curves of extensive air showers (EAS)
EAS development curve at energy of 10(16) - 10(18) eV measured by optical Cerenkov light
The data of optical Cerenkov light from extensive air shower observed at the core distance more than 1 Km at Akeno are reexamined. Applying the new simulated results, the shower development curves for the individual events were constructed. For the showers of 10 to 17th power eV the average depth at the shower maximum is determined to be 660 + or - 40 gcm/2. The shower curve of average development is found to be well described by a Gaisser-Hillas shower development function with above shower maximum depth
Gamma rays of energy or = 10(15) eV from Cyg X-3
The experimental data of extensive air showers observed at Akeno have been analyzed to detect the gamma ray signal from Cyg X-3. After muon poor air showers are selected, the correlation of data acquisition time with 4.8 hours X-ray period is studied, giving the data concentration near the phase 0.6, the time of X-ray maximum. The probability that uniform backgrounds create the distribution is 0.2%. The time averaged integral gamma ray flux is estimated as (1.1 + or - 0.4)x 10 to the -14th power cm(-2) sec(-1) for Eo 10 to the 15th power eV and (8.8 + or - 5.0)x 10 to the 14th power cm(-2) sec(-1) for Eo 6 x 10 to the 14th power eV
Ultra-high energy cosmic rays threshold in Randers-Finsler space
Kinematics in Finsler space is used to study the propagation of ultra high
energy cosmic rays particles through the cosmic microwave background radiation.
We find that the GZK threshold is lifted dramatically in Randers-Finsler space.
A tiny deformation of spacetime from Minkowskian to Finslerian allows more
ultra-high energy cosmic rays particles arrive at the earth. It is suggested
that the lower bound of particle mass is related with the negative second
invariant speed in Randers-Finsler space
Very High Energy Gamma Rays from PSR1706-44
We have obtained evidence of gamma-ray emission above 1 TeV from PSR1706-44,
using a ground-based telescope of the atmospheric \v{C}erenkov imaging type
located near Woomera, South Australia. This object, a -ray source
discovered by the COS B satellite (2CG342-02), was identified with the radio
pulsar through the discovery of a 102 ms pulsed signal with the EGRET
instrument of the Compton Gamma Ray Observatory. The flux of the present
observation above a threshold of 1 TeV is 1 10
photons cm s, which is two orders of magnitude smaller than the
extrapolation from GeV energies. The analysis is not restricted to a search for
emission modulated with the 102 ms period, and the reported flux is for all
-rays from PSR1706-44, pulsed and unpulsed. The energy output in the
TeV region corresponds to about 10 of the spin down energy loss rate of
the neutron star.Comment: 13 pages, latex format (article), 2 figures include
Testing the effective scale of Quantum Gravity with the next generation of Gamma Ray Telescopes
The actual potential of the next generation of Gamma Ray Telescopes in
improving the existing tests of an effective Quantum Gravity scale from the
study of the propagation delay for gamma rays of different energies coming from
a distant astrophysical source is discussed. It is shown that the existence of
a cosmological Gamma Ray Horizon, will impose very demanding conditions on the
observations of the telescopes to try to test a Quantum Gravity scale close to
the Planck mass.Comment: 14 pages, 7 figure
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