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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
- Tadross, A.L.
- Journal of the Korean astronomical society = 천문학회지
- 38, n.4
- pp.423-428
- 2005
- 원문 바로보기
The main physical parameters; the cluster center, distance, radius, age, reddening, and visual absorbtion; have been re-estimated and improved for the open cluster NGC 7086. The metal abundance, galactic distances, membership richness, luminosity function, mass function, and the total mass of NGC 7086 have been examined for the first time here using Monet et al. (2003) catalog.
462
- Chung, Eun-Jung
- Journal of the Korean astronomical society = 천문학회지
- 38, n.4
- pp.371-384
- 2005
- 원문 바로보기
Self-referencing method in revised-OTFTOOL is a new method in On-The-Fly(OTF) observation mode. It uses the source free regions of the observed frame as references instead of the OFFs references. We already analyzed and discussed its proprieties and advantages in the previous paper. In this paper, we make a statistical study about the self-referencing method by applying it to OTF mapping data of 27 Virgo spiral galaxies. We found that the self-referencing method solves the crooked baseline problem for every datacube. It straightens the baseline, and conserves the emissions. Compared with other data processing, the median filtering task 'mwflt' in AIPS, to use self-referencing method is more effective and safe not only to straighten the baseline but also to conserve the emission. For the strong CO galaxies, the data obtained by self-referencing method shows scarcely any difference from those reduced by conventional OFFs references and AIPS median filtering in the range of uncertainties. Undetected CO emissions in datacubes of conventional OFFs references are also not detected in those of self-referencing method. The self-referencing method is expected to save the observing time and simplify data reduction processes. Besides this, using self-referencing method will offer emission-free references more safely.
463
- Lee, Hye-Jin
- Journal of the Korean astronomical society = 천문학회지
- 38, n.3
- pp.345-355
- 2005
- 원문 바로보기
We present a photometric study of the star cluster system in the merging galaxy NGC 1487, based on the BI photometry obtained from the F450W and F814W images in the HST /WFPC2 archive data. We have found about 560 star cluster candidates in NGC 1487, using the morphological parameters of the objects. We have investigated several photometric characteristics of the clusters: color-magnitude diagrams (CMDs), color distribution, spatial distribution, age, size and luminosity function. The CMD of the bright clusters with 18.5 < B < 24 mag in NGC 1487 shows three major populations of clusters: a blue cluster population with <TEX>$(B-I){\le}0.45$</TEX>, an intermediate-color cluster population with <TEX>$0.45<(B-I){\le}1.55$</TEX>, and a red cluster population with (B - I) > 1.55. The intermediate-color population is the most dominant among the three populations. The brightest clusters in the blue and intermediate- color populations are as bright as <TEX>$B{\approx}18mag$</TEX> (<TEX>$M_B{\approx}-12mag$</TEX>), which are three magnitudes brighter than those in the red population. The blue and intermediate-color clusters are strongly concentrated on the bright condensations, while the red clusters are relatively more scattered over the galaxy. The CMD of these clusters is found to be remarkably similar to that of the clusters in the famous interacting system M51. From this we suggest that the intermediate-color clusters were, probably, formed during the merging process which occurred about 500 Myrs ago.
464
- Kyeong, Jae-Mann
- Journal of the Korean astronomical society = 천문학회지
- 38, n.4
- pp.415-422
- 2005
- 원문 바로보기
UBVIJHK photometry of the open cluster NGC 2194 are presented. Color-Magnitude diagrams of this cluster show well-defined main sequence and red giant clump. The main sequence also contains clear evidence of binary populations. Based on color-color diagrams, absolute magnitude of red giant clump, ZAMS fitting, and comparisons of observed color-magnitude diagrams with theoretical models, we derive following parameters for the cluster; reddening <TEX>$E(B-V)=0.44{\pm}0.04$</TEX>, age of log <TEX>$t{\sim}8.8$</TEX>, and finally distance of <TEX>$(m-M)_0=12.20{\pm}0.18$</TEX>.
465
- YAO YONGQIANG
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.335-336
- 2005
- 원문 바로보기
The working group for an infrared telescope(IRT) toward East Asian Observatory has been set up in EAMA6. This report declares the membership of IRT working group, reviews briefly the activities of promoting the IRT, and puts forward the future plan.
466
- KIM CHULHEE
- Journal of the Korean astronomical society = 천문학회지
- 38, n.1
- pp.1-6
- 2005
- 원문 바로보기
We searched for X-ray emission from the 665 galaxies inside and towards the nearby voids by analyzing the ROSAT All-Sky Survey (RASS) data as well as the ROSAT pointed observations (PSPC). As a result we have detected six X-ray emitting galaxies. Two (UGC 10205 and NGC 7509) are in the high density region in the local void, three (UGC 749, MCG +11-10-073, and Mrk 464) are towards the nearby voids, and UGC 32 is located in the low density region. We carried out a timing analysis for both Mrk 464 and UGC 32, and a spectral analysis for Mrk 464. The light curve of Mrk 464 shows the possibility of periodic X-ray flux variation and UGC 32 shows weak, but rapid variation.
467
- MATSUSHITA SATOKI
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.169-172
- 2005
- 원문 바로보기
We present CO(3-2), CO(2-1), and 230 GHz (1.3 mm) continuum images of nearby galaxies taken with the Submillimeter Array (SMA). Our main topic is to study the relation between higher-J molecular gas (e.g., CO J=3-2, 2-1) and nuclear activities (e.g., active galactic nuclei [AGNs] and starbursts). The nearby Seyfert 2 galaxy M51 shows strong CO(3-2) emission from the circumnuclear molecular gas, with an intensity twice as strong as that of the CO(1-0) emission. Strong CO(3-2) emission enhancement suggests that the circum nuclear molecular gas in M51 is warm and dense, which may be related to the AGN activities. Molecular gas in the nearby moderate starburst galaxy NGC 6946 is distributed along the large-scale bar or spiral arms and along the minibar, and the multi-J CO line images show very similar distribution to each other. For this galaxy, there is no clear enhancement in higher-J lines as seen in M51, which may be because NGC 6946 does not have clear AGN activities. Based on the results of these two galaxies, the physical conditions of the circum nuclear molecular gas may be related to the AGN activities. We also observed the nearby edge-on starburst galaxy NGC 3628 and the starburst/Seyfert composite galaxy NGC 4945 with the CO(2-1) line and 230 GHz (1.3 mm) continuum emission. These information will give us some hints for understanding the relation between nuclear activities and circum nuclear molecular gas and dust.
468
- YAO YONGQIANG
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.113-116
- 2005
- 원문 바로보기
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.
469
- YANAGISAWA KENSHI
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.109-112
- 2005
- 원문 바로보기
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 <TEX>$K_s$</TEX> bands and is dedicated to the survey of long period variable stars in the Galactic plane. The field of view is <TEX>$0.95 {\times} 0.95 deg^2$</TEX> which is covered by one HAWAII-2 RG detector of 2048 <TEX>${\times}$</TEX> 2048 pixels with the pixel size of <TEX>$18.5 {\mu}m\;{\times}\;18.5{\mu}m$</TEX>, that results in the sampling pitch of 1.6 arcsec/pixel. OAOWFC can sweep the area of <TEX>$840 deg^2$</TEX> every 3 weeks, attaining a limiting magnitude of 13 in <TEX>$K_s$</TEX> band. It allows us to observe long period variables embedded in the Galactic plane where interstellar extinction is severe in optical.
470
- SATO SHUJI
- Journal of the Korean astronomical society = 천문학회지
- 38, n.2
- pp.107-108
- 2005
- 원문 바로보기
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.