Studying a multi-dimensional structure of supernovae (SNe) gives important constraints on the mechanism of the SN explosion. Polarization measurement is one of the most powerful methods to study the explosion geometry of extragalactic SNe. Especially, Type Ib/c SNe are the ideal targets because the core of the explosion is bare. We have performed spectropolarimetric observations of Type Ib/c SNe with the Subaru telescope. We detect a rotation of the polarization angle across the line, which is seen as a loop in the Q - U plane. This indicates that axisymmetry is broken in the SN ejecta. Adding our new data to the sample of stripped-envelope SNe with high-quality spectropolarimetric data, five SNe out of six show a loop in the Q - U plane. This implies that the SN explosion commonly has a non-axisymmetric, three-dimensional geometry.

The status of Japan's planning of the optical/infrared astronomy projects for the 2010's is briefly reviewed. The road map shows a 30 m class extremely large ground based telescope project with advanced adaptive optics capability, JELT, and a mid-infrared optimized 3.5 m space telescope project, SPICA, as the top-priority major project to be accomplished probably on international collaboration basis.

We discuss the implications for the cosmic re-ionization from the optical afterglow spectrum of GRB050904 at z = 6.3

Using H I absorption alone, we attempt to separate H I absorption lines in quasar spectra into two categories; HDLs (Higher Density Lines) and LDLs (Lower Density Lines), and we discuss the difference in their physical properties. We deblend and fit all H I lines with Voigt profiles, and make an unbiased sample of H I lines covering a wide column density range ($12 < \log N_{HI} < 19$ cm$^{-2}$). To reduce the influence of line blending, we simultaneously fit several Lyman series lines. As a result of a two-point correlation analysis, we found that higher column density H I lines are clustering at $\Delta v < 200$ km s$^{-1}$, while lower ones at $\Delta v < 100$ km s$^{-1}$. We define HDLs as H I lines with $15<\log N_{HI} < 19$ cm$^{-2}$ and all H I lines within $\pm$200 km s$^{-1}$ of a line with $\log N_{HI} > 15$ cm$^{-2}$, and LDLs as others with $12 < \log N_{HI} < 15$ cm$^{-2}$. We found that the HDLs have smaller minimum $b$-values for a given column density than the LDLs. This difference is successfully reproduced by our hydrodynamic simulation. The LDLs seem to be cool or shock-heated diffuse IGM gas, while the HDLs are likely to be cooler dense gas near to galaxies.

We present initial results from an high-resolution imaging search for damped Ly$\alpha$ absorbers toward the high-redshift quasar APM 08279+5255 by using the Adaptive Optics system (AO) attached to the Subaru telescope. We detected in total 11 objects within a $23''\times23''$ field around the quasar. Among these detected objects, we identified a possible candidate for the galaxy giving rise to the damped Ly$\alpha$ absorption at z$_{abs}$=2.974 with a criteria of distance from the sight-line toward the quasar and luminosity.

Recently, a number of possible young globular clusters (GCs) have been found in some merging/interacting galaxies or starburst galaxies. On the other hand, it is well known that GCs are numerous in giant elliptical galaxies many of which are thought to be formed via major merger of galaxies. These facts lead us to a thought that the formation process of GCs could accompany galaxy – galaxy interaction followed by starburst. The archetypical starburst galaxy M82 is an ideal target to study the relation between galaxy interaction, starburst, and GC formation.

We made aperture masking optical interferometry experiments using up to 30 apertures and with a tip-tilt correction of wavefront error. We examined the performance of minimum redundant configurations of 11–30 sub-apertures on the pupil plane mask. These configurations have two advantages; the redundancy noise is as small as realized in non-redundant masking method, and the uv-coverage is as high as in speckle interferometry enabling to get reconstructed images without mask exchange. We also examined the effect of tip-tilt wavefront correction within a telescope pupil in front of the aperture masking optics. The light coherency between sub-apertures was shown to increase by the correction.

The starburst galaxy Tol 1924-416 was observed on May 18, 1985 using an echelle spectrograph coupled with a cooled CCD camera (CASPEC) mounted at the Cassegrain focus of the ESO 3.6-m telescope. The echellogram covers the 4320-5260 A spectral range with 0.33 A/pixel and a spatial extent of 12 arcsec at 1.5 arcsec seeing. The estimated spectral resolution is 25 kms−1 and the velocity calibration error is as small as 3 km s−1.

Short-wavelength adiabatic oscillations of an infinitesimally thin, rotating and self-gravitating gas disk in dynamical equilibrium are studied. The problem is formulated in terms of the theory of oscillations of gas spheres (i.e. stars) in order to help galactic and stellar seismologists towards their mutual understanding of their rather similar subjects.

The global modal analysis is applied to a family of models which are consistent with recent dynamical data of NGC 3115. A halo component at least as massive as the disk component is required to explain the apparent lack of spiral structures in NGC 3115.

An objective method involving a Fourier analysis is applied to seven galaxies for measuring the strength of spiral and bar components.