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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 86/122
851
- KIM JONG BOCK
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.15-16
- 1996
- 원문 바로보기
We discuss the possible ranges of electron neutrino degeneracy which is consistent with the inferred primordial abundances of the light elements. It is found that the electron neutrino degeneracy, [<TEX>${\epsilon}_e$</TEX>], up to order of <TEX>$10^{-1}$</TEX> is consistent with the present data.
852
- XU CHONGMING
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.17-18
- 1996
- 원문 바로보기
COBE's results on the anisotropy of the cosmic microwave background radiation (CMBR) is discussed. Some ambiguities in the linear GI cosmic perturbation theory are clarified. The problem of the last scattering surface and the deficiencies of the linear cosmic perturbation theory are mentioned. The possible ways to overcome the theoretical difficulties are discussed also.
853
- PARK BYEONG-GON
- Journal of the Korean astronomical society = 천문학회지
- 29, n.1
- pp.63-73
- 1996
- 원문 바로보기
The previous study of chemical evolution of the Galaxy is extended to the radial properties of the Galactic disk. The present model includes radial dependency of the time-dependent bimodal IMF, radial flow of material in the disk, and the change of type I supernova explosion rate with radial distance from the disk center as model parameters and observed gas and stellar density distributions and metallicity abundance gradient as observational constraints. The results of two models in this study explain the observed gas and stellar density distributions well, with the slope of the gas density gradient in the region of 4.5 kpc<r<12kpc as -0.136dex/kpc in model <TEX>$Y_1$</TEX> and -0.123dex/kpc in model <TEX>$Y_2$</TEX>, respectively, which fit well the observed gradient of -0.l1dex/kpc. The abundance gradient reproduced in model <TEX>$Y_1$</TEX> is getting flatter with decreasing radius, while that in model <TEX>$Y_2$</TEX> is getting steeper, which fits better the observed abundance gradient. This result shows the necessity of exponentially increasing type I supernova explosion rate with decreasing radius in order to explain the observed abundance gradient in the disk. The fitness of observed density distribution and star formation rate distribution justifies the reliability of time-dependent bimodal IMF as a compound quantitative chemical evolution model of the Galaxy. The temporal variations of metallicity gradients for carbon, nitrogen and oxygen are also shown.
854
- BROSCH NOAH
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.421-423
- 1996
- 원문 바로보기
855
- TSAY WEAN-SHUN
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.409-410
- 1996
- 원문 바로보기
Speckle Interferometer equipped with an ITT intensified CCD have been used on the NCUO ( National Central University Observatory, Taiwan) 24-inch telescope for studying the orbits of bright binary systems selected from the Yale's Bright Star Catalogue. The high resolution and high sensitivity ITT intensified solid state video camera ( F4577 ) has external gain and gate control functions which will simplify the design of the speckle camera and allow us to do precise speckle photometry. The goal of this project is trying to study the bright binary systems with separations between the average size of seeing disk and the diffraction limit of the 24-inch telescope. Recently some observing data have been reduced and compared with the other teams' results. We are now improving the data reduction technology and trying to use real time observing mode on the monthly routine observation.
856
- KANG HYESUNG
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.271-272
- 1996
- 원문 바로보기
Assuming that particles can be accelerated to high energies via diffusive shock acceleration process at the accretion shocks formed by the infalling flow toward the clusters of galaxies, we have calculated the expected spectrum of high-energy protons from the cosmological ensemble of the cluster accretion shocks. The model with Jokipii diffusion limit could explain the observed cosmic ray spectrum near <TEX>$10^{19}eV$</TEX> with reasonable parameters and models if about <TEX>$10^{-4}$</TEX> of the infalling kinetic energy can be injected into the intergalactic space as the high energy particles.
857
- WATANABE TETSUYA
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.291-294
- 1996
- 원문 바로보기
The .Japanese sun observing satellite, Yohkoh, has been operational for five years and her scientific instruments are still in good condition. They have revealed ample of evidences that solar flares were triggered by magnetic reconnection, which was, for the first time, clearly indicated to take place in the solar corona. Cusp structures in soft X-rays and a new type of hard X-ray sources at the top of flaring loops have strongly supported the scenario originally proposed by C-S-H-KP. Nonthermal energy input in hard X-rays and thermal energy estimated from soft X-rays are fundamentally consistent with the interpretation of thick-target and chromospheric-evaporation models (Neupert effect). X-ray jets, another discovery of Yohkoh, were also associated with magnetic reconnection, as a result of the interaction of emerging fluxes with pre-existing coronal loops. Temperature structures of active regions, quiet sun, and coronal holes had very dynamic differential-emission-measure (DEM) distributions and high-temperature tails of DEM were considered to come from the contribution of flare-like activity.
858
- LEE GEUNHO
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.459-460
- 1996
- 원문 바로보기
859
- GRIV EVGENY
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.355-355
- 1996
- 원문 바로보기
860
- TAKAHARA FUMIO
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.99-102
- 1996
- 원문 바로보기
I discuss implications of gamma-ray emission from blazars based on electron acceleration by shock waves in a relativistic jet. The number spectrum of electrons turns out to be a broken power law; while at low energies the power law index has a universal value of 2, at high energies it steepens to an index of 3 because of strong radiative cooling. This spectrum can basically reproduce the observed spectral break between X-rays and gamma-rays. I show that energetics of relativistic jets can be well explained by this model. I estimate physical quantities of the relativistic jets by comparing the prediction with observations. The results show that the jets are particle dominated and are comprised of electron-positron pairs. A connection between gamma-ray emission and radiation drag is also discussed.