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1968년 ~ 2024년까지 1,211 건의 한국천문학회지를 격월간 확인하실 수 있습니다.
- The Korean Astronomical Society (The Korean Astronomical Society)
- 계간 (Quarterly)
- ISSN : 1225-4614 (ISSN : 1225-4614)
1225-4614
- DB구축현황 : 1,211건 (DB Construction : 1,211 Articles)
총 게시글 1,211건
페이지 47/122
461
- SAWADA-SATOH SATOKO
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.183-186
- 2005
- 원문 바로보기
We present results of the VLBA observation toward the radio continuum and water maser emissions in a nearby LINER galaxy NGC 1052. The jet structure observed in 2000 is similar to that in 1998, and the two jet structures in 1998 and 2000 support the sub-luminal motion with apparent velocity of 0.26c. Distribution of water maser spots are located <TEX>${\~}$</TEX>0.05 pc shifted to southwest from the component which is supported to be the nucleus, and no rapid positional change of the water maser gas with respect to the central engine is seen from 1995 to 2000. The maser gas is positionally coincident with a plasma torus, and the position of the maser gas relative to the nucleus is stable from 1995 to 2000. The maser gas in NGC 1052 could be explained to be associated with the nuclear circumnuclear torus or disk like the situation found in the nucleus of NGC 4258.
462
- LEE HYUNG MOK
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.333-334
- 2005
- 원문 바로보기
Astronomical research in Asian Pacific region has been growing rapidly in recent years. However, most important papers have been published in well established existing journals in US and Europe because we do not have high impact international journals in this region. I review the current trends of the local journals of East Asian countries and propose to establish a new regional journal by combining domestic journals.
463
- KIM YONG HA
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.59-66
- 2005
- 원문 바로보기
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 <TEX>$O^+,\;OH^+$</TEX>, and <TEX>$HCO^+$</TEX> 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, <TEX>$O_2^+$</TEX>, changes little. Especially, the density profile of <TEX>$HCO^+$</TEX> 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 <TEX>$HCO^+$</TEX> ions are assumed to diffuse through non-moving ion background, <TEX>$O_2^+$</TEX>. 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.
464
- ARDI ELIANI
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.207-210
- 2005
- 원문 바로보기
We study the influence of rotation on the dynamical evolution of collisional single-mass stellar clusters up to core-collapse by using N-body simulations. Rotating King models which are characterized by dimensionless central potential parameter <TEX>$W_o$</TEX> and the rotation parameter <TEX>$W_o$</TEX> are used as initial models. Our results show that inner shells slowly contract until core-collapse phase is reached, followed by a slow expansion. Angular momentum is transported outward, while the core is rotating even faster than before, as predicted by gravogyro catastrophe theory. We confirm that rotation plays an important role in accelerating the dynamical evolution of stellar cluster, in particular in accelerating the core collapse.
465
- NOUMARU JUNICHI
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.101-102
- 2005
- 원문 바로보기
Subaru Telescope proposes to hold Subaru East Asia Youth School (Tentative Name) in 2005.
466
- Tadross, A.L.
- Journal of the Korean astronomical society = 천문학회지
- 38, n.3
- pp.357-363
- 2005
- 원문 바로보기
A deep stellar analysis is introduced for the poorly studied open cluster NGC 2509. The Near-IR database of the digital Two Micron All Sky Survey (2MASS) has been used to re-estimate and refine the fundamental parameters of the cluster, i.e. age, reddening, distance, and diameter. As well as, luminosity function, mass function, total mass, relaxation time, and mass segregation of NGC 2509 have been estimated here for the first time..
467
- YUAN CHI
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.337-338
- 2005
- 원문 바로보기
This is to summarize a joint discussion on the future of EAMA in EAMA6. The emphasis was placed on the near future instead of the distant future, Formation of the Working Groups as a means to carry the cooperation for the regions was generally agreed by the attendants of EAMA6 to be the best way toward the establishment of future East Asian Observatory (EAO). Association of Core Observatories (ACO) was proposed to bring resources and foster joint projects for EAMA activities.
468
- ANN HONG BAE
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.121-124
- 2005
- 원문 바로보기
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.
469
- OHASHI NAGAYOSHI
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.103-106
- 2005
- 원문 바로보기
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.
470
- ICHIMOTO KIYOSHI
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.307-310
- 2005
- 원문 바로보기
The Solar-B is the third Japanese spacecraft dedicated for solar physics to be launched in summer of 2006. The spacecraft carries a coordinated set of optical, EUV and X-ray instruments that will allow a systematic study of the interaction between the Sun's magnetic field and its high temperature, ionized atmosphere. The Solar Optical Telescope (SOT) consists of a 50cm aperture diffraction limited Gregorian telescope and a focal plane package, and provides quantitative measurements of full vector magnetic fields at the photosphere with spatial resolution of 0.2-0.3 arcsec in a condition free from terrestrial atmospheric seeing. The X-ray telescope (XRT) images the high temperature (0.5 to 10 MK) corona with improved spatial resolution of approximately 1 arcsec. The Extreme Ultraviolet Imaging Spectrometer (EIS) aims to determine velocity fields and other plasma parameters in the corona and the transition region. The Solar-B telescopes, as a whole, will enable us to explore the origins of the outer solar atmosphere, the corona, and the coupling between the fine magnetic structure at the photosphere and the dynamic processes occurring in the corona. The mission instruments (SOT/EIS/XRT) are joint effort of Japan (JAXA/NAO), the United States (NASA), and the United Kingdom (PPARC). An overview of the spacecraft and its mission instruments are presented.