http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Fitting of Light Curves for Microquasar V4641 Sgr
Shinji Nishiyama,Jun Fukue,Akira Arai,Kenya Watarai 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.4
We report the .tting results of theoretical light curves for microquasar V4641 Sgr. In this study, we apply a new accretion disk model that is presented by Fukue to observed R-band light curves of V4641 Sgr. The new model takes into account the geometrical thickness of the disk, so it may be able to describe the two deep minima of the observed light curves. The best-.t parameters show that the system has a relatively high inclination angle, i = 75±, and that the mass accretion rate is around the Eddington rate. We propose the importance of the geometry of the accretion disk to explain the deep minima observed in this object.
LABORATORY EXPERIMENTS OF OFF-AXIS MIRROR OPTICS OF ALUMINUM FOR SPACE INFRARED MISSIONS
Shinji Oseki,SHINKI OYABU,DAISUKE ISHIHARA,Keigo Enya,Kanae Haze,Takayuki Kotani,HIDEHIRO KANEDA,Miho Nishiyama,Lyu Abe,Tomoyasu Yamamuro 한국천문학회 2017 天文學論叢 Vol.32 No.1
We report our research on aluminum mirror optics for future infrared astronomical satellites. For space infrared missions, cooling the whole instrument is crucial to suppress the infrared background and detector noise. In this aspect, aluminum is appropriate for cryogenic optics, because the same material can be used for the whole structure of the instrument including optical components thanks to its excellent machinability, which helps to mitigate optical misalignment at low temperatures. We have fabricated aluminum mirrors with ultra-precision machining and measured the wave front errors (WFEs) of the mirrors with a Fizeau interferometer. Based on the power spectral densities of the WFEs, we confirmed that the surface accuracy of all the mirrors satisfied the requirements for the SPICA Coronagraph Instrument. We then integrated the mirrors into an optical system, and examined the image quality of the system with an optical laser. As a result, the total WFE is estimated to be 33 nm (rms) from the Strehl ratio. This is consistent with the WFEs estimated from the measurement of the individual mirrors.
DEVELOPMENT OF A CRYOGENIC TESTING SYSTEM FOR MID-INFRARED DETECTORS ON SPICA
Miho Nishiyama,Hidehiro Kaneda,Daisuke Ishihara,Shinji Oseki,Nami Takeuchi,Takahiro Nagayama,Takehiko Wada 한국천문학회 2017 天文學論叢 Vol.32 No.1
For future space IR missions, such as SPICA, it is crucial to establish an experimental method for evaluating the performance of mid-IR detectors. In particular, the wavelength dependence of the sensitivity is important but difficult to be measured properly. We are now preparing a testing system for mid-IR Si:As/Si:Sb detectors on SPICA. We have designed a cryogenic optical system in which IR signal light from a pinhole is collimated, passed through an optical filter, and focused onto a detector. With this system, we can measure the photoresponse of the detector for various IR light using optical filters with different wavelength properties. We have fabricated aluminum mirrors which are adopted to minimize thermal distortion effects and evaluated the surface figure errors. The total wavefront error of the optical system is 1.3 μm RMS, which is small enough for the target wavelengths (20 - 37 μm) of SPICA. The point spread function measured at a room temperature is consistent with that predicted by the simulation. We report the optical performance of the system at cryogenic temperatures.