모달창 닫기
- 홈으로 이동
1968년 ~ 2025년까지 1,227 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 : 1,227건 (DB Construction : 1,227 Articles)
총 게시글 1,227건
페이지 92/123
911
- DRURY L O'C
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.267-270
- 1996
- 원문 바로보기
The problem of the origin of cosmic rays is considered in an astronomical context and the current observational situation summarised. The evidence for acceleration in supernova remnants is critically examined.
912
- YERSHOV V. N.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.385-386
- 1996
- 원문 바로보기
A wide-field CCD detector for solar eclipse observations is discussed. The CCD is supposed to be of a moderate size, and the image of the corona is obtained by scanning the field of view. Results of the 1995 solar eclipse observation are shown which have been made with a prototype of the scanning CCD detector.
913
- XU ZHENTAO
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.441-442
- 1996
- 원문 바로보기
914
- KIM SANG-JOON
- Journal of the Korean astronomical society = 천문학회지
- 29, n.2
- pp.223-243
- 1996
- 원문 바로보기
We have constructed a line-by-line model of the A-X system of CO in order to analyze the CO bands appearing in the UV spectra of comets. The model includes electronic, rotational, vibrational transitions, excitations by solar UV radiation, and effects of neutral and electron collisions. The major bands of the A-X system occur in the <TEX>$1200 - 1800{\AA}$</TEX> range where the temporal variation of solar irradiation is significant. The solar spectrum in this spectral range shows many emission lines, which cause a significant Swings effect. We derived fluorescence efficiencies of the bands as functions of heliocentric velocity and cometocentric distance using a high resolution spectrum of the sun. We compared our model with a spectrum of comet P/Halley obtained with the IUE, and estimated that the UV Swings effects are less than 20 fluorescence efficiencies for the most bands of the A-X system. We discuss the temporal variation of solar UV irradiation and its effects on the fluorescence efficiencies. The study of the A-X system also requites knowledge of vibrational and rotational fluorescent processes in the infrared and radio regions because the majority of CO molecules in the coma is in the ground rotational states. The solar infrared spectrum near 5 microns, where the fundamental band of CO occurs, contains strong absorption lines of the fundamental band and hot bands of CO and its isotopes. We derived fluorescence efficiencies of the infrared band as functions of heliocentric velocity and cometrocentric distance. The solar absorption lines near 5 microns cause a 20 reduction of the g-factor of the fundamental band at heliocentric velocities close to 0 km/sec. We discuss the effects of neutral and electron collisions on the fluorescence efficiencies of the infrared and UV bands.
915
- YERSHOV V. N.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.427-428
- 1996
- 원문 바로보기
The Struve astrometric satellite which is being developed at Pulkovo Observatory in cooperation with Krasno-yarsk Institute of Applied Mechanics, S.I. Vavilov's State Optical Institute and some others space instrumentation institutes, will produce observations of a second epoch for the Hipparcos stars. The project is devoted to maintaining the Hipparcos coordinate system as well as extending it to a density of <TEX>$\approx$</TEX> 100 stars per square degree. Possibilities of submilliarcsecond accuracy of observations with single aperture on-board telescopes are discussed. Requirements to the optical scheme and to the dynamic properties of the spacecraft are formulated. CCD and microchannel plates are discussed as a focal assembly detectors.
916
- PARK SEOK JAE
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.97-98
- 1996
- 원문 바로보기
Variability of active galactic nuclei is now a well-known phenomenon. This remains to be fully explained by a theoretical model of the central engine. Time scales of AGN variability seem to range continuously from hours up to months. The short time scale variability must be related to the phenomena on the event horizon of the black hole, while the long one to those in the accretion disk or surrounding matter. Based on the axisymmetric, nonstationary model of the central engine, we discuss theoretical considerations on the variability of active galactic nucleus.
917
- PARK CHANGBOM
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.433-437
- 1996
- 원문 바로보기
We have analyzed the content of the Korean stone star chart. Ch'on-Sang-Yul-Cha-Bun-Ya-Ji-Do(here-after Ch'on-Sang-Do). In the star map we have found 1468 stars, 4 more than the Chinese star catalog Bo-Chun-Ga. The four extra stars form a constellation, Jong Dae Boo. The map projection law used in the star chart is found to be the polar equtorial and equidistance projection. The linear distance of an object on Ch'on-Sang-Do from the center is linearly proportional to the north polar angular distance. We have found from a statistical analysis that most stars with declination lower than 50 are at positions representing the epoch of around the first century. On the other hand, stars near the north pole with declination higher than 50 are at the epoch of about 1300, which is close to the time the chart was engraved. This implies that the original Ko-Gu-Rye Dynasty's star chart has been revised by astronomers of Cho-Sun Dynasty. We have also shown that stars on Ch'on-Sang-Do are engraved in such a way that their area is linearly proportional to the visual magnitude.
918
- YOON SO-YOON
- Journal of the Korean astronomical society = 천문학회지
- 29, n.2
- pp.119-136
- 1996
- 원문 바로보기
To examine the effect of neighboring galaxies on the gravitational lensing statistics, we performed numerical simulations of lensing by many galaxies. The models consist of a galaxy in the rich cluster like Coma, or a galaxy surrounded by field galaxies in <TEX>$\Omega_0 = 1$</TEX> universe with <TEX>$\Omega_{gal} = 0.1,\;\Omega_{gal} = 0.3\;or\;\Omega_{gal}=1.0\;,\;where\;\Omega_{gal}$</TEX> is the total mass in galaxies. Field galaxies either have the same mass or follow Schechter luminosity function and luminosity-velocity relation. Each lensing galaxy is assumed to be singular isothermal sphere (SIS) with finite cutoff radius. In most simulations, the lensing is mainly due to the single galaxy. But in <TEX>$\Omega_{gal} = 3$</TEX> universe, one out of five simulations have 'collective lensing' event in which more than two galaxies collectively produce multiple images. These cases cannot be incorporated into the simple 'standard' lensing statistics calculations. In cases where 'collective lensing' does not occur, distribution of image separation changes from delta function to bimodal distribution due to shear induced by the surrounding galaxies. The amount of spread in the distribution is from a few <TEX>$\%\;up\;to\;50\%$</TEX> of the mean image separation in case when the galaxy is in the Coma-like cluster or when the galaxy is in the field with <TEX>$\Omega_{gal} = 0.1\;or\;\Omega_{gal}=0.3.$</TEX> The mean of the image separation changes less than <TEX>$5\%$</TEX> compared with a single lens case. Cross section for multiple image lensing turns out to be relatively insensitive to the presence of the neighboring galaxies, changing less than <TEX>$5\%$</TEX> for Coma-like cluster and <TEX>$\Omega_{gal}=0.1,\;0.3$</TEX> universe cases. So we conclude that Coma-like cluster or field galaxies whose total mass density <TEX>$\Omega_{gal}<0.3$</TEX> do not significantly affect the probability of multiple image lensing if we exclude the 'collective lensing' cases. However, the distribution of the image separations can be significantly affected especially if the 'collective lensing' cases are included. Therefore, the effects of surrounding galaxies may not be negligible when statistics of lensing is used to deduce the cosmological informations.
919
- KURTANIDZE OMAR M.
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.325-326
- 1996
- 원문 바로보기
We present the Programme of Monitoring of Flare Stars in the Orion aggregate by. CCD based. Photometer mounted at the Newtonian focus of 70/98/210-cm meniscus telescope through glass imaging quality C1 filter (3900<TEX>${\AA}$</TEX>/800<TEX>${\AA}$</TEX>) with a time resolution of 0.5-1.0 min.
920
- LIU HANPING
- Journal of the Korean astronomical society = 천문학회지
- 29, n.suppl1
- pp.175-176
- 1996
- 원문 바로보기