• Title/Summary/Keyword: SYSTEMATIC EVOLUTION

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A Systematic Study on the Bryozoas from the South Sea in Korea I. Cheilostomata (한국 남해산 태충류의 계통분류학적 연구 I. 순구류)

  • 서지은
    • Animal Systematics, Evolution and Diversity
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    • v.8 no.1
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    • pp.141-160
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    • 1992
  • The systematic study on the bryozoans from the South SEa in Korea was done with the materials collected at 49 localities from 1965 to 1991. As a result, 57 species in two suborders of cheilostomaous bryozoans were identified, which seven species, Electra tenella, Labioporella bursaria, Dendrobeania longispinosa, Sinupetraliella gigantea, Cryptosula pallasiana, Hippopodina feegeensis and Durystomella bilabiata were new to Korean fauna. The unrecorded species and the species which need remarking were described with plates.

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YONSEI NEARBY SUPERNOVA EVOLUTION INVESTIGATION (YONSEI) SUPERNOVA CATALOGUE

  • KIM, YOUNG-LO;KANG, YIJUNG;LEE, YOUNG-WOOK
    • Publications of The Korean Astronomical Society
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    • v.30 no.2
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    • pp.485-486
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    • 2015
  • We use light-curve fitting models (MLCS2k2, SALT2, and SNooPy) as implemented in SNANA to make the YOnsei Nearby Supernova Evolution Investigation (YONSEI) Supernova Catalogue. The catalogue consists of several hundred Type Ia supernovae (SNe Ia) in the redshift range from 0.01 to 1.35, and provides distance moduli, light-curve shape parameters, and color or extinction values for each supernova. This data set will be used to study the dependence of SNe Ia luminosities on the host galaxy morphologies. In this paper, we present the YONSEI Supernova Catalogue and preliminary systematic tests for the catalogue.

Determination of Age and Metallicity of Early-Type Galaxies hosting Type Ia Supernovae

  • Kang, Yijung;Kim, Young-Lo;Lim, Dongwook;Chung, Chul;Lee, Young-Wook
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.59.1-59.1
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    • 2013
  • Type Ia supernovae (SNe) are providing the most conclusive evidence for accelerating universe with dark energy in observational cosmology. In these investigations, look-back time evolution of SNe luminosity is regarded as negligible on the basic assumption. However, several recent works present some systematic differences among hosts which have different characteristics of stellar population. For more direct investigation, we are proceeding with our YONSEI (YOnsei Nearby Supernovae Evolution Investigation) project. Only early-type hosts in our catalogue were chosen in order to estimate the luminosity-weighted mean age and metallicity directly using Single Stellar Population (SSP) models and ignore the effect from the dust extinction. Observations using low-resolution spectrographs are still in progress at Las Campanas Observatory with 2.5m telescope and at McDonald Observatory with 2.7m telescope. We have thus far obtained spectra for 30 early-type hosts. After weak emission line correction, Lick/IDS absorption-line indices are measured and YEPS spectroscopic evolution model was applied to determine mean population ages and metallicities. Our preliminary results show that SNe Ia hosted in older galaxies seem to be brighter at 1.4 - 3 sigma levels, however, more observations and analyses are still needed to confirm this correlation.

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The Dark Energy Research Using Type Ia Supernovae in the GMT Era: The Evolution-Free and Dust-Free Test

  • Kim, Young-Lo;Kang, Yijung;Lim, Dongwook;Lee, Young-Wook
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.59.2-59.2
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    • 2013
  • The luminosity evolution of Type Ia supernova (SN Ia) and dust extinction play major roles in the systematic uncertainties in the SN cosmology. In order to overcome these obstacles, here we propose to use GMT-GMACS to take spectra for early-type host-galaxies of SNe Ia in the redshift range between 0.2 and 1.0. This high-redshift sample will be taken from Dark Energy Survey (DES), which expects more than 200 early-type hosts at this redshift range. They will be compared with nearby early-type hosts, for which we are now obtaining low-resolution spectra. We will select host-galaxies of same population age range for both nearby and high-redshift samples to reduce the possible evolution effect. Since we are dealing with early-type galaxies, our test is also less affected by dust extinction. We expect that our evolution-free and dust-free dark energy test will provide more robust results on the nature of dark energy.

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Intrinsic alignments of emission line galaxies at z ~1.4 from the FastSound redshift survey

  • Tonegawa, Motonari;Okumura, Teppei;Totani, Tomonori;Dalton, Gavin;Yabe, Kiyoto
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.2
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    • pp.54.1-54.1
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    • 2017
  • Intrinsic alignments (IA), the coherent alignment of intrinsic galaxy orientations, can be a source of a systematic error of weak lensing surveys. The redshift evolution of IA also contains information about the physics of galaxy formation and evolution. We present the first measurement of IA at high redshift, z~1.4, using the spectroscopic catalog of blue star-forming galaxies of the FastSound redshift survey, with the galaxy shape information from the Canada-Hawaii-France telescope lensing survey. The IA signal is consistent with zero with power-law amplitudes fitted to the projected correlation functions for density-shape and shape-shape correlation components, $A_{\delta+}=-0.0040\pm 0.0754$ and $A_{++}=-0.0159\pm 0.0271$, respectively. These results are consistent with those obtained from blue galaxies at lower redshifts (e.g., $A_{\delta+}=0.0035_{-0.0389}^{+0.0387}$ and $A_{++}=0.0045_{-0.0168}^{+0.0166}$ at z=0.51 from the WiggleZ survey), suggesting no strong redshift evolution of IA. The upper limit of the constrained IA amplitude corresponds to a few percent contamination to the weak-lensing shear power spectrum, resulting in systematic uncertainties on the cosmological parameter estimations by $-0.035<\Delta \sigma_8<0.026$ and $-0.025<\Delta \Omega_{\mathrm m}<0.019$.

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3GPP GERAN Evolution System Employing High Order Modulation and Turbo Coding: Symbol Mapping Based on Priority (터보코딩 및 고차변조를 적용하는 3GPP GERAN 진화 시스템: 비트 신뢰도 기반의 심볼 매핑)

  • Oh, Hyeong-Joo;Choi, Byoung-Jo;Hwang, Seung-Hoon;Choi, Jong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.6A
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    • pp.607-613
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    • 2008
  • In this paper, we investigate the performance of SMP-assisted 3GPP GERAN evolution system employing high order modulation and turbo coding. When applying the SMP which maps systematic bits into highly reliable bit positions, it is confirmed that there is the performance gain for the modulation and coding schemes of 16QAM(DAS-8) as well as 32QAM(DAS-11) by link level simulation.