During this year, I have studied the feature of the active region filaments. Using two different observations which are H-alpha fibrils and EUV threads, we have determined filament chirality. We found clear hemispheric pattern. Namely, filaments in the northern (southern) hemisphere have dextral (sinistral) fibrils in H-alpha observations obtained from the Big Bear Solar Observatory. On the other hand, negative (positive) closings of filament threads in EUV images observed with TRACE appear in the northern (southern) hemisphere, respectively. These indicate that positive (negative) chirality filaments are surrounded by sinistral (dextral) fibrils. Since fibrils and EUV threads are along magnetic field lines, we suggest that filament and surrounding feature have a same helicity sign.

We used two-dimensional hydrodynamical simulations and one-dimensional radiative transport radiation hydrodynamical simulations to investigate the properties of dense ejecta clumps (bullets) in Type Ia and core collapse supernova remnants, motivated by the observation of protrusions probably caused by clumps in Tycho…s remnant (SN 1572) and the Vela supernova remnant. The ejecta were assumed to freely expand into an ambient medium with a constant density. Ejecta clumps with an initial density contrast < 100 relative to their surroundings are found to be rapidly fragmented and decelerated. In order to cause a pronounced protrusion on the blast wave front of the remnant as observed in the Vela remnant, a density contrast of ~1000 may be required. This result applies to moderately large clumps; smaller clumps would require an even larger density contrast. Clumps can create ring structure in the shell of the Vela remnant and we investigate the possibility that RX J0852--4622, an apparent supernova remnant superposed on Vela, is actually part of the Vela shell. The heating from the radioactive decay of Ni56 -> Co56 -> Fe56 in supernova ejecta during the first ~10 days is a possible mechanism to produce the clumping, which induces a forward shock that compresses the ejecta gas into a shell. When the flow tends toward a freely-expanding state, the thickness of the shell takes up < 0.5% of the radius of the bubble, and the density contrast across the shell reaches >~ 100 in a narrow region limited by numerical resolution. The resultant interaction of the clumps with the remnant is expected at a stage as indicated by our simulations.

Opto-mechanical analysis is an essential to develop a large telescope. In order to achieve the required performance specification of the telescope it should be optimized under static, thermal and dynamic loads by the high fidelity finite element analyses integrated with optical performance analyses. In addition, the active optics support system with lightweight mirror should be considered to correct a distorted image during the telescope operation which is designed and optimized by the extensive opto-mechanical analyses.
Detailed opto-mechanical analyses will be discussed in this seminar for the lightweight mirrors, active optics support system, overall telescope structure under various environments including gravity, thermal, wind and seismic loads. The overall performance of telescope will be addressed as well based on the Line of Sight (LOS) sensitivity equations.

We used two-dimensional hydrodynamical simulations and one-dimensional radiative transport radiation hydrodynamical simulations to investigate the properties of dense ejecta clumps (bullets) in Type Ia and core collapse supernova remnants, motivated by the observation of protrusions probably caused by clumps in Tycho…s remnant (SN 1572) and the Vela supernova remnant. The ejecta were assumed to freely expand into an ambient medium with a constant density. Ejecta clumps with an initial density contrast 100 relative to their surroundings are found to be rapidly fragmented and decelerated. In order to cause a pronounced protrusion on the blast wave front of the remnant as observed in the Vela remnant, a density contrast of ~1000 may be required. This result applies to moderately large clumps; smaller clumps would require an even larger density contrast. Clumps can create ring structure in the shell of the Vela remnant and we investigate the possibility that RX J0852--4622, an apparent supernova remnant superposed on Vela, is actually part of the Vela shell. The heating from the radioactive decay of Ni56 -> Co56 -> Fe56 in supernova ejecta during the first ~10 days is a possible mechanism to produce the clumping, which induces a forward shock that compresses the ejecta gas into a shell. When the flow tends toward a freely-expanding state, the thickness of the shell takes up < 0.5% of the radius of the bubble, and the density contrast across the shell reaches >~ 100 in a narrow region limited by numerical resolution. The resultant interaction of the clumps with the remnant is expected at a stage as indicated by our simulations.

The frequencies of the harmonics of standing Alfven waves depend on the distribution of mass along the magnetic field line that sustains the waves. This fact is the basis of the inversion techniques (normal mode magnetospheric seismology) to estimate the plasma mass density variation along the magnetic field from the frequencies of observed ULF waves. However, the technique has not been used extensively because it is difficult to accurately determine the frequencies. Wave observations from geostationary (e.g., GOES) or near-geostationary (e.g., CRRES) satellites provide the best chance of a successful implementation of the technique because the satellites accumulate the spectral information on the harmonics with minimal variations in frequency. By using the frequencies observed by these satellites in a numerical density modeling technique, we find an equatorial mass density enhancement and much milder density variations along the field line than previously thought

I talk about the newly developed near-infrared (0.9-2.5um) imager and spectrograph ISLE for the Cassegrain focus (f/18) of the 1.88 m telescope at Okayama Astrophysical Observatory (OAO). The detector of ISLE is a HAWAII 1024 x 1024 HgCdTe array. The field of view and the pixel scale are 4.2 x 4.2 arcmin^2 and 0.25 arcsec / pixel, respectively. The pixel scale is optimized to sample the light profile of a point source under typical near-infrared seeing condition of OAO (around 1 arcsec). The spectroscopy mode of ISLE provides a capability of long-slit spectroscopy with a spectral resolution R ranging from 500 to 4800. We developed a low-noise readout electronics for the detector and achieved a readout noise lower than 10 e with single sampling readout. Applying a special readout technique, we also succeeded to suppress so-called \"reset anomaly\" of the detector significantly.