[en] Cosmic string loops aggregate the expanding collisionless matter to form a galactic halo, in which the density falls as γ^-2 such as derived from the rotation curves of spiral galaxies. The total amount of the collected matter is estimated to be 10¹³ (Gμ/10^-7)^3/2M solar mass and a size of the loop which can aggregate the matter varies depending whether it is the cold matter or the hot matter. (author)

[en] On February 24, 1987, a supernova was found in the Large Magellanic Cloud at a Chilean observatory, and was named SN 1987A. The Large Magellanic Cloud is present adjoining this Milky Way, and at the distance of about 150,000 light years from the earth. The explosion of a supernova at a short distance like this may be said to be the event for the first time in modern space observation. Further, the shocking thing was that about 3 hours before the discovery in Chile, the signals of neutrinos which seemed to be due to the explosion were recorded on the proton decay experimental device, Kamiokande, which is installed at 1000 m underground at Kamioka Mine. It is the epoch-making event also for elementary particle physics that the astronomical observation was carried out by using neutrinos. It was shown by this observation the theory that 99% of the energy released by the explosion of a supernova is emitted as neutrinos is correct. Supernova and pulsar, the means of observing superhigh energy gamma ray, the selection of the observation site, international cooperation, the cooperation of research organizations, the construction of the observation base and the results of observation of the upper limit value and gamma ray flare by JANZOS are reported. (K.I.)

[en] In order to derive informations about the primordial fluctuation from the observable density structure at the present, we have to know a behavior of nonlinear density fluctuation. Several topics related to this problem are reviewed. (author)

[en] A newly-born pulsar is covered by the expanding dense envelope, and high-energy charged particles accelerated near the pulsar are effectively converted into high-energy neutrinos with energies of 10¹³ -- 10¹⁴ eV through meson production and its decay. Such a opaque phase continues for a couple of months. This model was first proposed by Berezinsky, but we will show that his flux estimation is too high by a factor of --10⁵. This reduction is needed because the particle flux is limited by the accompanying phenomena such as the source power of high-energy cosmic rays and the light element production rate by spallation nuclear reaction. (auth.)

[en] If a newly born neutron star in SN1987A is a powerful injector of ultra high energy (UHE) protons, UHE γ-rays will be emitted by bombardment of supernova ejecta with these UHE particles. We compute energy spectrum of the UHE γ-rays generated by monoenergetic protons using Monte Carlo simulations at the period of high flux when the column density is 30∼100 g/cm². If the column density of the ejecta is less than ∼100 g/cm², low energy γ-rays do not increase as E^-2, like the case for Cyg X-3, but they have much harder spectrum close to E^-1. The expected numbers of PeV and TeV region γ-rays per hour are at least 0.16 counts (L_p/10⁴¹ ergs)(S/(50 m)²)(d/56 kpc)^-2 and 132 counts (L_p/10⁴¹ ergs)(S/30000 m²)(d/56 kpc)^-2 where L_p, S and d are the proton luminosity, the area of detectors, and the distance to LMC, respectively. (author)

[en] Propagation of light in a clumpy universe is examined for redshift and luminosity. Taking a spherical void model and Swiss Chesse model, the modification is found to be the third order of (Hrsub(b)/c) for the redshift and the first order of it for the luminosity, rsub(b) being the radius of a void or a Swiss Cheese hole. (author)

[en] Cooling and contraction of baryonic matter are investigated in a galaxy formation scenario by string loops. It is found that ∼ 3 % of virialized baryonic matter has cooled down and contracted. This virialized object may have a disk-halo structure and be considered a galaxy. (author)

[en] In the Einstein-de Sitter model, the spherically symmetric less-dense perturbation is investigated with an aim to discuss the observed void in distribution of galaxies. In the nonlinear regime, the enlargement of the perturbed region occurs. For the neutrino dominated model, the enlargement of the void of nucleon number is estimated. It is argued also that the cellular structure in the galaxy distribution might be explained by the compression of matter squeezed between the expanding voids. (author)

[en] This article consists from two parts: the first part is concerned with the subject given in the title and the second part is a tribute to Albert Einstein in the occasion of WYP2005 celebrating his Miracle year, which is given in the Appendix. There are two ways to violate the Lorentz Symmetry of our 4-dimensional space-time; one is to violate the relativity principle since Galileo's relativity and another one is to modify the energy-momentum relation in the high energy without introducing the preferred system. In the tribute to Einstein in the Appendix, 'four public faces of Einstein and his visit to Japan in 1922' are described. (author)

[en] Head-on collision of a charged particle with plane gravitational waves is considered. We calculate a cross section of conversion scattering from gravitational waves into electromagnetic waves by a particle with charge Ze. In the high-speed limit, this cross section is given as σ asymptoticaly equals (4/3)(4π).(e²G/c⁴)Z²γ⁴, γ being the Lorentz factor. (author)