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        검색결과 496

        381.
        1998.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present UBV CCD photometry of Be 2, previously unstudied open cluster. Our photometry covers a field of 3'.2×3'.8 of the sky centered on the cluster, which is slightly smaller than the cluster diameter estimated to be about 260". We have determined the reddening, distance, age and metallicity of the cluster by fitting the Pad ova isochrones to the observed stellar distributions in color-magnitude diagram as well as main sequence fitting: E(B-V)=0.8±0.05, (m-M)o=13.6±0.1, log(t) =8.9±0.1, and Z=0.008. The present photometry shows that Be 2 is a distant open cluster of intermediate age. that it is a distant intermediate-age open duster.
        4,300원
        382.
        1998.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The wide field (~20'×20') CCD photometry has been performed for more than 4,000 stars over a whole region of NGC 362 which is located inside the SMC halo. The Color-Magnitude diagram (CMD) and luminosit function (LF) for red giant branch (RGB) stars are presented, discussing a distinct bump along the RGB and some blue stars appearing in the blue horizontal branch (BHB) and above BHB. The anomalous globular cluster NGC 362 with highly populated red horizontal branch (RHB) stars is compared with the another anomalous globular cluster NGC 288 with highly populated BHB stars. A metal-rich, young blue component and metal-'poor, old red component of the SMC halo stars are examined.
        4,000원
        383.
        1997.12 구독 인증기관·개인회원 무료
        385.
        1997.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The BV photographic photometry was made for 1714 stars (V < 19.5m) in NGC 6752, using 83 photoelectric stars and many secondary photographic standard stars over the area of 3.3' - 11.3' from the cluster center. Their data and finding chart are presented.
        5,400원
        386.
        1997.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present a near-infrared (K, J-K) color magnitude diagram(CMD) for the central region of a metal poor globular cluster NGC 6535. Our near-infrared data are combined with published optical BV data to construct (K, V-K) CMD. A new metallicity estimate is made by applying the relation between metallicity and MKo as proposed by Frogel, Cohen and Persson(1983). Our value is [Fe/H] = -1.66+-0.06, which is slightly higher than other results previously reported.
        4,200원
        387.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        We have estimated a metal abundance of [Fe/H]= -0.48 ± 0.14 dex, a reddening of E(B- V)= 0.30 mag, an age of 2.0 ± 0.4 Gyr, and a distance of 7.9 ± 0.8 kpc for Tombaugh 2 using the Washington filter system.
        388.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        We have estimated a metal abundance of [Fe/H]= -0.04 ± 0.05 dex, a reddening of E(B- V)= 0.28 mag, an age of 1.1 ± 0.1 Gyr, and a distance of 2.5 ± 0.2 kpc for NGC 1245 using the Washington filter system.
        389.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        390.
        1996.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Galactic open clusters NGC 1907 and NGC 1912 are known as a binary cluster candidate by Subramaniam et al.(1995). With the SNUO 0.6m telescope, UBV CCD photometric observations were performed for 62 stars in NGC 1907 within the area of 8′×8′ 8′×8′ and 203 stars in NGC 1912 within the area of 15′×15′ 15′×15′ area. We obtained C-M and C-C diagrams. Their mean reddenings are E(B-V) = 0.50±0.03 0.50±0.03 for NGC 1907 and 0.27±0.03 0.27±0.03 for NGC 1912. The distance moduli are estimated as 10.9±0.15 10.9±0.15 and 10.4±0.10 10.4±0.10 for NGC 1907 and NGC 1912, respectively. The ages for these clusters are 400±50Myr 400±50Myr for NGC 1907 and 150±30Myr 150±30Myr for NGC 1912. The distance difference of the two clusters is 300pc and the age difference is 150Myr. These results imply that the two clusters are not physically connected.
        4,000원
        391.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        The first large-format CCD color-magnitude diagram (CMD) in the B and V passbands is presented for the Galactic globular cluster M53 (NGC 5024). We have discovered 117 new blue straggler (BS) candidates in the field of M53. The analysis of bright BS stars (V <19.0) clearly shows a bimodal radial distribution, with a high frequency in the inner and outer regions. The distribution is similar to that found in M3, a globular cluster with similar central density and concentration.
        392.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        393.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        There is an excess gamma flux from the general direction of the Galactic North Pole compared with that from the south when allowance is made for the contribution from CR interactions with the HI gas (Osborne et al., 1994). The extent to which it is in accord with the predictions of Wdowczyk and Wolfendale (1990 a,b) for gamma rays secondary to very high energy CR escaping from the VIRGO cluster is examined and it is claimed that the observations may well be of the order of those expected.
        394.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        In order to investigate the spatial orientation of the spin vectors of galaxies in the Virgo cluster, we carried out a detailed identification of all the certain and possible member disk galaxies with four UK Schmidt Telescope (UKST) III a-j direct plates digitized by the Automated Plate Measuring System (APM). As a result, a relatively large and complete database with no selection effect of the member galaxies has been established. We provide the APM measured values of the position angle (P.A.) and diameters at the isophotal level of 24.5 mj / arcsec2. Based on this newly generated database, an initial study on the spatial orientation of the spin vectors of galaxies in the Virgo cluster is shown.
        395.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        Based on the database of 128 disk galaxies (66 SO, 62 S and Irr) mailnly compiled from Kent and Gunn (1982) and Doi et a1.(1995) which is complete down to m < 15.6 mag within a radius of 3°, the orientation of spin vectors of disk galaxies of the Coma cluster has been analyzed. The results confirm the morphological dependence of the orientation of disk galaxies found from the analsis of the Virgo cluster. Common features of orientation of disk galaxies of both clusters are outlined.
        398.
        1996.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present the color-magnitude diagrams (CMD) of more than 24,000 stars in the field of an intermediate age open cluster M11, based on wide field CCD imaging. The morphology of the CMDs varies strikingly as the distance from the center of the cluster increases. From the surface number density analysis, we confirm the mass segregation effect in this cluster: the bright, massive stars are centrally more concetrated than the faint, low mass stars. The slope of the field-corrected surface density with respect to magnitude progressively increases as the radius increases, up to r = 5'. Most of the field stars in or near the cluster main sequence band and in the bright part of the red stars in the CMDs appear to be nearly at the same distance as M11, and they are considered to be the major component of disk stars in the Sagittarius-Carina arm.
        4,000원
        399.
        1996.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present a study of the metallicity of the old open cluster NGC 1245 , based on the Washington CCD photometry obtained using the 0.6 m telescope at the Sobaeksan Observatory, Korea. NGC 1245 has been known to be a unique cluster among the known open clusters in the sense that the previous metallicity estimates for this cluster are much larger (by 3σ) than the value expected from the radial metallicity gradient of the old open clusters in Our galaxy. We have estimated the metallicity of the cluster red giants using the four color-color diagrams, obtaining a value for the mean metallicity of [Fe/H] = -0.04±0.05 dex. The total error including the error of the metallicity calibration, 0.15 dex, is 0.16 dex. The metallicity estimate of NGC 1245 we have obtained in this study is smaller than previous estimates, and is consistent with the radial metallicity gradient of the old open clusters, showing that the mean metallicity of NGC 1245 is not abnormally high. The reddening, distance, and age of the cluster have also been derived using the isochrones based on the convective overshooting models: the reddening E(B-V) = 0.28±0.03; the distance d = 2.5±0.2 kpc (the corresponding galactocentric distance is RGC = 10.7 kpc, and the distance from the galactic plane is z = -0.4 kpc); and the age t = 1.1±0.1 Gyrs.
        4,600원
        400.
        1996.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have obtained the J K images of the central region of the globular cluster M3 (NGC5272), using the 256×256 InSb array. We present JK photometry of bright red giant branch stars in the central 2'.2×2'.2 region of M3. The infrared color-magnitude diagrams are presented. The comparison of the red giant branch of M3 with that of M13 confirms that both globular clusters have similar metal abundances.
        4,000원