간행물
천문학회지 KCI 등재 SCOPUS Journal of The Korean Astronomical Society
- 발행기관 한국천문학회
- 자료유형 학술지
- 간기 반년간
- ISSN 1225-4614 (Print)2288-890X (Online)
- 수록기간 1968 ~ 2024
- 주제분류 자연과학 > 천문학 자연과학 분류의 다른 간행물
- 십진분류KDC 440DDC 520
권호리스트/논문검색
제38권 제2호 (2005년 6월) 68건
1.
2005.06
구독 인증기관 무료, 개인회원 유료
CN and CH band strengths for fourteen bright giants in the globular cluster M71 have been measured from archival spectra obtained with the Multiple Mirror Telescope. Adding the collected. data from the literature we confirm a bimodality of CN distribution on the red giant branch and the honzontal branch, and CN-CH anti-correlations on the lower giant branch and horizontal branch. However a CN-CH anti-correlation on the upper red giant branch is not quite clear as those of other branches. The small number If statistics could not be excluded as a possible cause. To confirm this, a greater number of sample stars are needed. We also confirm that the ratio of CN-strong to CN-weak stars is quite different from that in 47 Tuc, although the anti-correlation between CN and CH bands, the bimodality of the CN distribution, and the spatial distribution of CN stars in M71 are found to be similar to those III 47 Tuc.
4,000원
2.
2005.06
구독 인증기관 무료, 개인회원 유료
We have conducted observations toward the molecular cloud associated with the H II region Sh 156 in 13CO(J = 1-0), C18O(J = 1-0), and CS(J = 2 -1) using the TRAO 14 m telescope. Combining with existing 12CO(J = 1- 0) data of the Outer Galaxy Survey, we delineated the physical properties of the cloud. We found that there is a significant sign of interaction between the H II region and the molecular gas. We estimated the masses of the molecular cloud, using three different techniques; the most plausible mass is estimated to be 1.37 X 105M⊙, using a conversion factor of X = 1.9 X 1020cm-2 (K km s-1)-1, and this is similar to virial mass estimate. This implies that the cloud is gravitationally bound and in virial equilibrium even though it is closely associated with the H II region. In addition to existing outflow, we found several MSX and IRAS point sources associated with dense core regions. Thus, more star forming activities other than the existing H II region are also going on in this region.
4,000원
3.
2005.06
구독 인증기관 무료, 개인회원 유료
The authors have assembled a sample of 80 W UMa binary systems (42 W-subtype and 38 A-subtype) whose light curves have all been solved by means of the recent W-D code and combined with up-to-date radial velocity solutions. The absolute parameters (masses, radii and luminosities) have been derived (without any constraint on the physical parameters). The main results of this paper are: (1) the mass-luminosity relations for both W&A-subtypes. as well as for all W UMa contact binaries have been shown, (2) the mass-radius relations have been found for both subtypes, (3) some remarks on the evolution status have been presented.
4,800원
4.
2005.06
구독 인증기관 무료, 개인회원 유료
A new ion transport code for planetary ionospheric studies has been developed with consideration of velocity differences among ion species involving ion-ion collision. Most of previous planetary ionosphere models assumed that ions diffuse through non-moving ion and neutral background in order to consolidate continuity and momentum equations for ions into a simple set of diffusion equations. The simplification may result in unreliable density profiles of ions at high altitudes where ion velocities are fast and their velocity differences are significant enough to cause inaccuracy when computing ion-ion collision. A new code solves explicitly one-dimensional continuity and momentum equations for ion densities and velocities by utilizing divided Jacobian matrices in matrix inversion necessary to the Newton iteration procedure. The code has been applied to Martian nightside ionosphere models, as an example computation. The computed density profiles of O+, OH+, and HCO+ differ by more than a factor of 2 at altitudes higher than 200 km from a simple diffusion model, whereas the density profile of the dominant ion, O2+, changes little. Especially, the density profile of HCO+ is reduced by a factor of about 10 and its peak altitude is lowered by about 40 km relative to a simple diffusion model in which HCO+ ions are assumed to diffuse through non-moving ion background, O2+. The computed effects of the new code on the Martian nightside models are explained readily in terms of ion velocities that were solved together with ion densities, which were not available from diffusion models. The new code should thus be expected as a significantly improved tool for planetary ionosphere modelling.
4,000원
5.
2005.06
구독 인증기관 무료, 개인회원 유료
KWANG-IL SEON, WONYONG HAN, DAE-HEE LEE, UK-WON NAM, JANG-HYUN PARK, IN-SOO YUK, HO JIN, KYUNG WOOK MIN, KWANG-SUN RYU, JERRY EDELSTEIN, ERIC KORPELA
The FIMS (Far-ultraviolet IMaging Spectrograph; also known as SPEAR, Spectroscopy of Plasma Evolution from Astrophysical Radiation) is the primary payload of the STSAT-1, the first Korean science satellite, which was launched in September, 2003. The FIMS performs spectral imaging of diffuse far-ultraviolet emission with the unprecedented wide field of view and the relatively good spectral resolution. We present far-ultraviolet spectral observations of highly ionized interstellar medium including supernova remnants, superbubbles, soft X-ray shadows, and the molecular hydrogen fluorescent emission lines. The FIMS has detected He II, C III, 0 III, O IV, Si IV, O VI, and H2 fluorescent emission lines. The emission lines arise in shocked or thermally heated and in photo-ionized gases. We present an overview of the FIMS instrument and its initial observational results.
3,000원
6.
2005.06
구독 인증기관 무료, 개인회원 유료
The latest scientific highlights obtained with the Subaru telescope are given together with its current status and on-going instrumentation. We have been successfully operating the telescope and 8 observatory instruments (including an adaptive optics system) since January 1999, when the first light was accomplished. Open-use of Subaru began in December 2000. Subaru has a unique capability of its prime focus among other 8-10 meter class telescopes and has an excellent imaging performance as a result of its sophisticated active optics combined with the high stability of the sky at Mauna Kea. Scientific highlights are given on the discoveries of the most distant galaxies, spiral structure on a protoplanetary disk around AB Aur, and planetesimal belts in the debris disk around β Pic. Brief summaries are given for three new instruments: the Multi-Object Infrared Camera and Spectrograph (MOIRCS), 188 element adaptive optics system, and Fiber Multi-Object Spectrograph (FMOS)
3,000원
7.
2005.06
구독 인증기관 무료, 개인회원 유료
We had the first committee meeting of the East Asia VLBI Consortium during the EAMA6 meeting held in Seoul. A VLBI network composed of telescopes in the East Asia region could provide extreme properties, and the coordination of them has been expected. The Committee of the East Asia VLBI Consortium is a standing committee to promote activities of the consortium, in which participating countries at present are China, Japan, and Korea over eight institutes/observatories. Here we introduce the Consortium and Committee.
3,000원
8.
2005.06
구독 인증기관 무료, 개인회원 유료
We are undertaking an extra-solar planet search around G-type giant stars by means of Doppler technique using an iodine absorption cell installed to the high dispersion echelle spectrograph for the 188 cm reflector at Okayama Astrophysical Observatory (Okayama Planet Search Program, OPSP). Having detected the first planet candidate (Sato et al. 2003)the search has been proved very promising. Taking advantage of this success, we are trying to develop OPSP to an international collaborative work. We here report the current status of our efforts for establishing such collaborations, namely, those with Chinese and Korean astronomers. We also propose to establish an East-Asian network to search for extra-solar planets around G-type giant stars with the transit detecting technique as well as the Doppler technique, asking other persons/groups to join us to enjoy the planet search.
3,000원
9.
2005.06
구독 인증기관 무료, 개인회원 유료
Construction of the Virtual Observatory (VO) is a great concern to the astronomical community in the 21st century. We present an outline of the concept and necessity of the va and the current status of various VO projects including the 15 national ones and the International Virtual Observatory Alliance (IVOA). We summarize the possible science cases that could be solved by using the VO data/tools, real science cases which are the results of using current VO tools, and our own work of using AstroGrid, the United Kingdom national VO, for a research on star formation history of galaxies.
3,000원
10.
2005.06
구독 인증기관 무료, 개인회원 유료
SPICA (Space Infrared Telescope for Cosmology and Astrophysics) is an infrared astronomical satellite with a 3.5 m cooled telescope which is very powerful in mid- and far- infrared observations and makes complementary role to JWST and Herschel. SPICA will be launched at ambient temperature without any cryogen into the Sun-Earth L2 orbit and cooled down in space to 4.5 K with use of efficient radiative cooling and mechanical coolers. The present status of SPICA and the developments of the satellite system are reported.
3,000원
11.
2005.06
구독 인증기관 무료, 개인회원 유료
ASTRO-F is the first Japanese dedicated infrared astronomical satellite which will be launched in 2005FY and is now in the final stage of the development. ASTRO-F is a 70 cm aperture cryogenically cooled telescope and designed for the infrared survey with much higher sensitivity and angular resolution than IRAS. We present the current status of the mission, focal plane instruments, and the observation plan now being discussed.
3,000원
12.
2005.06
구독 인증기관 무료, 개인회원 유료
The first Space-VLBI project, VSOP, started successfully with the launch of the dedicated space-VLBI satellite HALCA in 1997. The project has been in scientific operation in the 1.6 GHz and 5 GHz bands, and studies have been done mainly of the jet phenomena related to active galactic nuclei. A second generation space- VLBI project, VSOP-2, has been planned by the working group formed at ISAS/JAXA with many collaborators. The spacecraft is planned to observe in the 8, 22 and 43 GHz bands with cooled receivers for the two higher bands, and with a maximum angular resolution at 43 GHz (7 mm) of about 40 micro-arcseconds. The VSOP-2 satellite will also have the capability of the phase-reference and full polarization observations, which will produce more powerful results than those of the VSOP project. Far-future space-VLBI projects following VSOP and VSOP-2, have a large potential to achieve enough resolution and sensitivity to satisfy astronomers in future.
3,000원
13.
2005.06
구독 인증기관·개인회원 무료
Subaru Telescope proposes to hold Subaru East Asia Youth School (Tentative Name) in 2005.
14.
2005.06
구독 인증기관 무료, 개인회원 유료
The Submillimeter Array (SMA), a collaborative project of the Smithsonian Astrophysical Observatory (SAO) and the Academia Sinica Institute of Astronomy & Astrophysics (ASIAA), has begun operation on Mauna Kea in Hawaii. A total of eight 6-m radio telescopes comprise the array with currently working receiver bands at 230, 345, and 690 GHz. The array will have 8 receiver bands covering the frequency range of 180-900 GHz. The backend is flexible analog-digital correlator with a full bandwidth of 2GHz, which is very powerful to cover several line emissions simultaneously. The current status and future plans of the SMA are described with emphasis on Taiwanese efforts.
3,000원
15.
2005.06
구독 인증기관·개인회원 무료
The situations and locations of the Asian astronomical observatories are overviewed. I propose to construct a medium size Infrared Telescope at a good site in the Asian district.
16.
2005.06
구독 인증기관 무료, 개인회원 유료
We present the design, expected performance, and current status of the wide field near-infrared camera (OAOWFC) now being developed at Okayama Astrophysical Observatory, NAOJ, NINS. OAOWFC is a near-infrared survey telescope whose effective aperture is 91cm. It works at Y, J, H, and Ks bands and is dedicated to the survey of long period variable stars in the Galactic plane. The field of view is 0.95 X 0.95 deg2 which is covered by one HAWAII-2 RG detector of 2048 X 2048 pixels with the pixel size of 18.5 μm X 18.5 μm, that results in the sampling pitch of 1.6 arcsec/pixel. OAOWFC can sweep the area of 840 deg2 every 3 weeks, attaining a limiting magnitude of 13 in Ks band. It allows us to observe long period variables embedded in the Galactic plane where interstellar extinction is severe in optical.
3,000원
17.
2005.06
구독 인증기관 무료, 개인회원 유료
The program of site survey in western China has been initiated by the National Astronomical Observatories of China(NAOC) toward large telescope facilities. The program is carried out in aspects of remote studies and local surveys. The preliminary results show that the eastern Pamirs and Ali area in Tibet may be the best candidates for further monitoring. The site survey group of NAOC will proceed to set up site testing stations on the selected sites and perform monitoring and campaign in 2005.
3,000원
18.
2005.06
구독 인증기관 무료, 개인회원 유료
CURRENT STATUS OF THE INSTRUMENTS, INSTRUMENTATION AND OPEN USE OF OKAYAMA ASTROPHYSICAL OBSERVATORY
Current instrumentation activities and the open user status of Okayama Astrophysical Observatory (OAO) are reviewed. There are two telescopes in operation and one telescope under reforming at OAO. The 188cm telescope is provided for open use for more than 200 nights in a year. The typical over-subscription rate of observation proposals for the 188cm telescope is ~ 1.5 - 2. The 50cm telescope is dedicated to ɤ-ray burst optical follow-up observation and is operated in collaboration with Tokyo Institute of Technology. The 91cm telescope will become a new very wide field near-infrared camera in two years. The high-dispersion echelle spectrograph (HIDES) is the current primary instrument for the open use of the 188cm telescope. Two new instruments, an infrared multi-purpose camera (ISLE) and an optical low-dispersion spectrograph (KOOLS), are now under development. They will be open as common use instruments in 2006.
3,000원
19.
2005.06
구독 인증기관 무료, 개인회원 유료
High resolution images of the nuclear regions of nearby galaxies show that nuclear spirals are preponderant in normal galaxies as well as in active galaxies. These nuclear spirals, especially the grand-design nuclear spirals are found to be formed by the gas flow driven by the bar. Hydrodynamical simulations exploring a wide range of parameter space show that the morphology of nuclear spirals depends not only on the inner dynamics but on the global dynamics resulting from the global mass distribution of galaxies. Thus, the nuclear morphology can be a diagnostic tool for the inner dynamics of galaxies when the global mass distribution is taken into account.
3,000원
20.
2005.06
구독 인증기관 무료, 개인회원 유료
In this paper, we argue that the gigahertz peaked spectrum (GPS) quasars are special blazars, blazars in dense and dusty gas enviornment. The ROSAT detection rate of GPS quasars is similar to that of flat spectrum radio quasars (FSRQs), suggesting that the relativistic jets in GPS quasars are oriented at small angle to the line of sight. Due to strong inverse Compton scattering off infrared photons from dense and dusty nuclear interstellar media in GPS quasars, most of them may have significant soft gamma-ray and X-ray emission, which is consistent with ASCA X-ray observations. Because Compton cooling in GPS quasars is stronger than that in FSRQs, synchrotron emission in GPS quasars may less dominate over thermal emission of the accretion disk and hot dust, hence most GPS quasars show low optical polarization and small variability, consistent with observations. We suggest that it is the significant radio emission of electron/positron pairs produced by the interaction of gamma-rays with the dense gas and dust grains in GPS quasars that makes GPS quasars show steep radio spectra, low radio polarization, and relatively faint VLBI/VLBA cores. Whether GPS quasars are special blazars can be tested by gamma-ray observations with GLAST in the near future, with the detection rate of GPS quasars being similar to that of FSRQs.
3,000원
