• Title/Summary/Keyword: Dwarf

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DARK MATTER IN THE UNIVERSE : BRIEF REVIEW

  • Oh, Kap-Soo
    • Publications of The Korean Astronomical Society
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    • v.7 no.1
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    • pp.31-37
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    • 1992

  • Dark matter in various size of scales is reviewed briefly. The evidence of dark matter in dwarf spheroidal galaxies is still uncertain. However there is no doubt about the existence of dark matter in larger scales. Many proposed candidates for dark matter are still speculative. Several possibilities of direct detection of dark matter are proposed.

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THE PROPERTIES OF THE STELLAR NUCLEI WITH THE HOST GALAXY MORPHOLOGY IN THE ACSVCS

  • Lee, Hyun-Chul
    • Journal of The Korean Astronomical Society
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    • v.44 no.5
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    • pp.195-200
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    • 2011

  • We have revisited the ACS Virgo Cluster Survey (ACSVCS), a Hubble Space Telescope program to obtain ACS/WFC g and z bands imaging for a sample of 100 early-type galaxies in the Virgo Cluster. In this study, we examine 51 nucleated early-type galaxies in the ACSVCS in order to look into the relationship between the photometric and structural properties of stellar nuclei and their host galaxies. We morphologically dissect galaxies into five classes. We note that (1) the stellar nuclei of dwarf early-type galaxies (dS0, dE, and dE,N) are generally fainter and bluer with g > 18.95 and (g-z) < 1.40 compared to some brighter and redder counterparts of the ellipticals (E) and lenticular galaxies (S0), (2) the g-band half-light radii of stellar nuclei of all dwarf early-type galaxies (dS0, dE, and dE,N) are smaller than 20 pc and their average is about 4 pc, and (3) the colors of red stellar nuclei with (g - z) > 1.40 in bright ellipticals and lenticular galaxies are bluer than their host galaxies colors. We also show that most of the unusually "red" stellar nuclei with (g-z) > 1.54 in the ACSVCS are the central parts of bright ellipticals and lenticular galaxies. Furthermore, we present multi photometric band color - color plots that can be used to break the age-metallicity degeneracy particularly by inclusion of the thermally pulsing-asymptotic giant branch (TP-AGB) phases of stellar evolution in the stellar population models.

  • https://doi.org/10.5303/JKAS.2011.44.5.195 인용 PDF KSCI

Formation and evolution of mini halos around a dwarf galaxy sized halo - Candidate sites for the primordial globular clusters

  • Chun, Kyungwon;Shin, Jihye;Kim, Sungsoo S.
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.2
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    • pp.34.2-34.2
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    • 2015

  • We aim to investigate the formation of primordial globular clusters (GCs) in the isolated dwarf galaxy (${\sim}10^{10}M_{sun}$) with cosmological zoom-in simulations. For this, we modified cosmological hydrodynamic code, GADGET-3, in a way to include the radiative heating/cooling that enables gas particles cool down to T~10K, reionization (z < 8.9) of the Universe, UV shielding ($n_{shield}$ > $0.014cm^{-3}$), and star formation. Our simulation starts in a cubic box of a side length 1Mpc/h with 17 million particles from z = 49. The mass of each dark matter (DM) and gas particle is $M_{DM}=4.1{\times}10^3M_{sun}$ and $M_{gas}=7.9{\times}10^2M_{sun}$, respectively, thus the GC candidates can be resolved with more than hundreds particles. We found the following results: 1) mini halos with the more interactions before merging into the main halo form the more stars and thus have the higher star mass fraction ($M_{star}/M_{total}$), 2) the mini halos with the high $M_{star}/M_{total}$ can survive longer and thus spiral into closer to the galactic center, 3) the majority of them spiral into bulge, but some of them can survive until the last as baryon-dominated system, like the GC.

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