466 research outputs found

    ASCA Observation of the Low-Luminosity Seyfert 1.5 Galaxy NGC 5033

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    We present the results of an ASCA observation of the low-luminosity Seyfert 1.5 galaxy NGC 5033. A point-like X-ray source with a luminosity of 2.3x10^{41} erg s^{-1} in the 2--10 keV band (at 18.7 Mpc; Tully 1988, AAA045.002.054) was detected at the nucleus. The X-ray light curve shows variability on a timescale of ~10^4 s with an amplitude of ~20%. The X-ray continuum is represented by a weakly absorbed (N_H~9x10^{20} {cm^{-2}) power-law with a photon index of 1.72+/-0.04, which is quite similar to Seyfert 1 galaxies with higher luminosities. A Fe Kalpha emission line is detected at 6.40^{+0.08}_{-0.06} keV (redshift corrected) and the equivalent width is 290+/-100 eV. The line width is unresolved. The narrower line width and larger equivalent width compared to Seyfert 1s imply that fluorescent Fe Kalpha emission from matter further out from the center than the accretion disk significantly contributes to the observed Fe Kalpha line. We suggest that fluorescent Fe Kalpha emission from the putative torus contributes to the observed Fe Kalpha line.Comment: 17 pages, To appear in PASJ, Vol. 51, No.

    Structure of air shower disc near the core

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    The longitudinal structure of the air shower disk is studied by measuring the arrival time distributions of air shower particles for showers with electron size in the range 3.2 x 10 to the 5.5. power to 3.2 x 10 to the 7.5 power in the Akeno air-shower array (930 gcm squared atmospheric depth). The average FWHM as a parameter of thickness of air shower disk increases with core distances at less than 50m. AT the present stage, dependence on electron size, zenith angle and air shower age is not apparent. The average thickness of the air shower disk within a core distance of 50m could be determined by an electromagnetic cascade starting from the lower altitude

    Search for long-lived massive particles in extensive air showers

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    Air showers containing delayed sub-showers which may be produced by a long-lived massive particle have been investigated by using twelve detectors. Ten events have been selected out as the candidates. However, a definite conclusion cannot be reached at the present time

    Lateral distribution of electrons of air showers

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    The lateral distribution of electrons (LDE) of the air showers of size 10 to the 5th power to 10 to the 6th power was studied within one MU. It was found that the LDE of the air showers observed is well represented by NKG function except for vicinity of the core. It was also found that LDE measured by thin scintillators does not differ from that measured by thick ones of 50mm thickness

    Character of energy flow in air shower core

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    Energy per charged particle near the core of air showers was measured by 9 energy flow detectors, which were the combination of Cerenkov counters and scintillators. Energy per particle of each detector was normalized to energy at 2m from the core. The following results were obtained as to the energy flow: (1) integral frequency distribution of mean energy per particle (averaged over 9 detectors) is composed of two groups separated distinctly; and (2) showers contained in one group show an anisotropy of arrival direction

    Transition effect of air shower particles in plastic scintillators

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    The transition effect of air shower particles in the plastic scintillators near the core was measured by scintillators of various thickness. The air showers selected for the measurement were of 10,000. Results obtained are as follows: (1) the multiplication of shower particles in the scintillators is less than 20% for that of 50 mm thickness; (2) dependence of the transition effect on age parameter is not recognized within the experimental errors
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