• Title/Summary/Keyword: near-infrared photometry

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NEAR-INFRARED PHOTOMETRY OF THE STAR CLUSTERS IN THE DWARF IRREGULAR GALAXY IC 5152

  • Kyeong, Jae-Mann;Sung, Eon-Chang;Kim, Sang-Chul;Sohn, Sang-Mo Tony;Sung, Hyun-Il
    • Journal of The Korean Astronomical Society
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    • v.39 no.4
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    • pp.89-94
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    • 2006
  • We present JHK-band near-infrared photometry of the star clusters in the dwarf irregular galaxy IC 5152. After excluding possible foreground stars, a number of candidate star clusters are identified in the near-infrared images of IC 5152, which include young populations. Especially, five young star clusters are identified in the(J-H, H-K) two color diagram and the total extinction values toward these clusters are estimated to be $A_v=2-6$ from the comparison with the theoretical values given by the Leitherer et al.(1999)'s theoretical star cluster model.

NEAR-INFRARED PHOTOMETRY OF METAL RICH GLOBULAR CLUSTER M71

  • 경재만;변용익;천문석
    • Journal of Astronomy and Space Sciences
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    • v.14 no.2
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    • pp.194-201
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    • 1997
  • We have carried out JK near-infrared photometry for the central region of the metal rich globular cluster M71, whose (K, J - K) color-magnitude diagram is presented here. Using two independent methods we derive the distance modulus to M71, 12.89 and 12.86 $pm0.12$ respectively. The former is derived using the HB luminosity $M_{Ko}$(HB) = -1.15 for globular clusters having metallicity between -1.0 to -0.3 (Kuchinski et al. 1995). The latter is derived through a comparison with IR photometry of stars in the similar metallicity cluster 47 Tuc. We also estimate the reddening to M71, E(J - K) = 0.13, based on E(B - V) = 0.04 of 47 Tuc.

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RED GIANT BRANCH OF THE METAL POOR GLOBULAR CLUSTERS: I. BUMP, TIP, AND DISTANCE FROM NEAR INERARED PHOTOMETRY

  • Sohn Y.J.;Kim J.W.;Kang A.
    • Journal of Astronomy and Space Sciences
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    • v.23 no.2
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    • pp.91-96
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    • 2006
  • We use near-infrared observations of eight selected Galactic globular clusters to estimate their distances by comparing the observed and theoretically predicted K magnitudes of the red giant branch bumps and tips. The K magnitude levels of the RGB bump and tip have been measured from the luminosity function of the selected RGB stars in the clusters. Theoretical absolute $M_k$ magnitudes of the RGB bump and tip are taken from the Yonsei-Yale isochrones. Comparing the observed apparent K magnitude with the derived absolute $M_k$ magnitude, we calculate the distance moduli of the clusters. We discuss the dependency of the derived distance modulus on the cluster age and the uncertainty of the distance measurement from the near-infrared photometry of the RGB bump and tip.

JK PHOTOMETRY OF BRIGHT GIANTS IN NGC6712

  • KYEONG JAE-MANN;BYUN YONG-IK
    • Journal of The Korean Astronomical Society
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    • v.31 no.2
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    • pp.127-140
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    • 1998
  • With a large format near-infrared camera at the 2.2-m telescope on Mauna Kea Observatory, we performed J K near-infrared observations for the metal rich globular cluster NGC6712. This cluster lies near the galactic plane and therefore suffers heavy reddening. We present the near-infrared color-magnitude diagram and also derive the metallicity ([Fe/H] ${\~}-0.96{\pm}0.27$) as well as its distance modulus ((m - M) ${\~}13.42{\pm}0.12$).

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GROUND-BASED NEAR-INFRARED CENSUS FOR YOUNG STAR CLUSTERS IN THE DWARF STARBURST GALAXY NGC 1569

  • Kyeong, Jae-Mann;Sung, Eon-Chang;Kim, Sang-Chul;Chaboyer, Brian
    • Journal of The Korean Astronomical Society
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    • v.43 no.1
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    • pp.1-8
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    • 2010
  • JHK near-infrared photometry of star clusters in the dwarf irregular/dwarf starburst galaxy NGC 1569 are presented. After adopting several criteria to exclude other sources (foreground stars, background galaxies, etc.), 154 candidates of star clusters are identified in the near-infrared images of NGC 1569, which include very young star clusters. Especially, from analysis based on theoretical background, we found ten very young star clusters near the center of NGC 1569. The total reddening values toward these clusters are estimated to be $A_V$=1-9 mag from comparison with the theoretical estimates given by the Leitherer et al. (1999)'s star cluster model.

PHOTOMETRIC STUDY OF IC 2156

  • TADROSS, A.L.;HENDY, Y.H.M.
    • Journal of The Korean Astronomical Society
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    • v.49 no.2
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    • pp.53-57
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    • 2016
  • We present an optical UBVRI photometric analysis of the poorly studied open star cluster IC 2156 using Sloan Digital Sky Survey data in order to estimate its astrophysical properties. We compare these with results from our previous studies that relied on the 2MASS JHK near-infrared photometry. The stellar density distributions and color-magnitude diagrams of the cluster are used to determine its geometrical structure, real radius, core and tidal radii, and its distance from the Sun, the Galactic plane, and the Galactic center. We also estimate, the age, color excesses, reddening-free distance modulus, membership, total mass, luminosity function, mass function, and relaxation time of the cluster.

2MASS Near-Infrared Photometry of the Old Open Cluster Trumpler 5

  • Kim, Sang-Chul;Kyeong, Jae-Mann;Sung, Eon-Chang
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.1
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    • pp.53.2-53.2
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    • 2010
  • Using the JHK 2MASS near-infrared data, we present photometry results for the old open cluster (OC) Trumpler 5 (Tr 5). From the near-infrared color-magnitude diagrams of Tr 5, we have located the position of the red giant clump (RGC) stars, and used the mean magnitude of the RGC stars in K-band to estimate the distance to Tr 5. From the Padova isochrone fittings, we have estimated the reddening, metallicity, and age of Tr 5. These parameters generally agree well with those obtained from the previous studies on Tr 5 and confirms that this cluster is an old OC with metallicity being metal-poorer than solar abundance, located in the anti-Galactic center region.

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