• Title/Summary/Keyword: profile decomposition

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HI superprofiles of galaxies from THINGS and LITTLE THINGS

  • Kim, Minsu;Oh, Se-Heon
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.2
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    • pp.68.3-69
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    • 2021
  • We present a novel profile stacking technique based on optimal profile decomposition of a 3D spectral line data cube, and its performance test using the HI data cubes of sample galaxies from HI galaxy surveys, THINGS and LITTLE THINGS. Compared to the previous approach which aligns all the spectra of a cube using their central velocities derived from either moment analysis, single Gaussian or hermite h3 polynomial fitting, the new method makes a profile decomposition of the profiles from which an optimal number of single Gaussian components is derived for each profile. The so-called superprofile which is derived by co-adding all the aligned profiles from which the other Gaussian models are subtracted is found to have weaker wings compared to the ones constructed in a typical manner. This could be due to the reduced number of asymmetric profiles in the new method. A practical test made on the HI data cubes of the THINGS and LITTLE THINGS galaxies shows that our new method can extract more mass of kinematically cold HI components in the galaxies than the previous results. Additionally, we fit a double Gaussian model to the superprofiles whose S/N is boosted, and quantify not only their profile shapes but derive the ratio of the Gaussian model parameters, such as the intensity ratio and velocity dispersion ratio of the narrower and broader Gaussian components. We discuss how the superprofile properties of the sample galaxies are correlated with their other physical properties, including star formation rate, stellar mass, metallicity, and gas mass.

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Program Development of Integrated Expression Profile Analysis System for DNA Chip Data Analysis (DNA칩 데이터 분석을 위한 유전자발연 통합분석 프로그램의 개발)

  • 양영렬;허철구
    • KSBB Journal
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    • v.16 no.4
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    • pp.381-388
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    • 2001
  • A program for integrated gene expression profile analysis such as hierarchical clustering, K-means, fuzzy c-means, self-organizing map(SOM), principal component analysis(PCA), and singular value decomposition(SVD) was made for DNA chip data anlysis by using Matlab. It also contained the normalization method of gene expression input data. The integrated data anlysis program could be effectively used in DNA chip data analysis and help researchers to get more comprehensive analysis view on gene expression data of their own.

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Ranking Decision Method of Retrieved Documents Using User Profile from Searching Engine (검색 엔진에서 사용자 프로파일을 이용한 문서 순위결정 방법)

  • Kim Yong-Ho;Kim Hyeong-Gyun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.10 no.9
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    • pp.1590-1595
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    • 2006
  • This paper proposes a technique of user oriented document ranking using user refile to provide more satisfied results which reflect preference of specific users. User profile is constructed to represent his or her preference. User pfofile consists of 'term array' and 'preference vector' according to the interest field of one. And the User profile for a particular person is updated by 'user access', 'latent relaeon', 'User Profile' proposed in this paper. The latent structures of documents in same domain are analysed by singular value decomposition(SVD). Then, the rank of documents is determined by comparison of user profile with analyzed document on the basis of relevance.

Kennicutt-Schmidt law with H I velocity profile decomposition in NGC 6822

  • Park, Hye-Jin;Oh, Se-Heon;Wang, Jing;Zheng, Yun;Zhang, Hong-Xin;de Blok, W.J.G.
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.1
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    • pp.32.3-33
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    • 2021
  • We present H I gas kinematics and star formation activities of NGC 6822, a dwarf galaxy located in the Local Volume at a distance of ~ 490 kpc. We perform profile decomposition of the line-of-sight velocity profiles of the high-resolution (42.4" × 12" spatial; 1.6 km/s spectral) H I data cube taken with the Australia Telescope Compact Array (ATCA). For this, we use a new tool, the so-called BAYGAUD (BAYesian GAUssian Decompositor) which is based on Bayesian Markov Chain Monte Carlo (MCMC) techniques, allowing us to decompose a line-of-sight velocity profile into an optimal number of Gaussian components in a quantitative manner. We classify the decomposed H I gas components of NGC 6822 into bulk-narrow, bulk-broad, and non_bulk with respect to their velocity and velocity dispersion. We correlate their gas surface densities with the surface star formation rates derived using both GALEX far-ultraviolet and WISE 22 micron data to examine the impact of gas turbulence caused by stellar feedback on the Kennicutt-Schmidt (K-S) law. The bulk-narrow component that resides within r25 is likely to follow the linear extension of the Kennicutt-Schmidt (K-S) law for molecular hydrogen (H2) at the low gas surface density regime where H I is not saturated.

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SURFACE PHOTOMETRY OF THREE SPIRAL GALAXIES ESO 598-G009, NGC 1515 AND NGC 7456

  • CHOI YOUNG-JUN;PARK BYEONG-GON;YOON TAE SEOG;ANN HONG BAE
    • Journal of The Korean Astronomical Society
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    • v.31 no.2
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    • pp.141-160
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    • 1998
  • We have conducted BV RI CCD surface photometry of three spiral galaxies ESO 598-G009, NGC 1515 and NGC 7456. In order to understand the morphological properties and luminosity distribution characteristics for each galaxy, we derived isophotal map, position angle profile, ellipticity profile, luminosity profile, color profile and color contour map. ESO 598-G009, which has a bright bulge component and a ring, shows a trace of gravitational interaction. NGC 1515 is a spiral galaxy with a bar and dust lane. NGC 7456 shows typical characteristics of a late type spiral galaxy.

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GLOBAL Hɪ PROPERTIES OF GALAXIES VIA SUPER-PROFILE ANALYSIS

  • Kim, Minsu;Oh, Se-Heon
    • Journal of The Korean Astronomical Society
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    • v.55 no.5
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    • pp.149-172
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    • 2022
  • We present a new method which constructs an Hɪ super-profile of a galaxy which is based on profile decomposition analysis. The decomposed velocity profiles of an Hɪ data cube with an optimal number of Gaussian components are co-added after being aligned in velocity with respect to their centroid velocities. This is compared to the previous approach where no prior profile decomposition is made for the velocity profiles being stacked. The S/N improved super-profile is useful for deriving the galaxy's global Hɪ properties like velocity dispersion and mass from observations which do not provide sufficient surface brightness sensitivity for the galaxy. As a practical test, we apply our new method to 64 high-resolution Hɪ data cubes of nearby galaxies in the local Universe which are taken from THINGS and LITTLE THINGS. In addition, we also construct two additional Hɪ super-profiles of the sample galaxies using symmetric and all velocity profiles of the cubes whose centroid velocities are determined from Hermite h3 polynomial fitting, respectively. We find that the Hɪ super-profiles constructed using the new method have narrower cores and broader wings in shape than the other two super-profiles. This is mainly due to the effect of either asymmetric velocity profiles' central velocity bias or the removal of asymmetric velocity profiles in the previous methods on the resulting Hɪ super-profiles. We discuss how the shapes (𝜎n/𝜎b, An/Ab, and An/Atot) of the new Hɪ super-profiles which are measured from a double Gaussian fit are correlated with star formation rates of the sample galaxies and are compared with those of the other two super-profiles.

The effect of simulated acid rain on microbial community structure in decomposing leaf litter

  • Cha, Sangsub;Lim, Sung-Min;Amirasheba, Bahitkul;Shim, Jae-Kuk
    • Journal of Ecology and Environment
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    • v.36 no.4
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    • pp.223-233
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    • 2013
  • Acid deposition is one of the most serious environmental problems in ecosystems. The present study surveyed the effects of simulated acid rain on leaf litter mass loss and microbial community in the decomposing leaf litter of Sorbus anifolia in a microcosm at $23^{\circ}C$ and 40% humidity. Microbial biomass was measured by substrate-induced respiration (SIR) and phospholipid fatty acids (PLFAs), and the microbial community structures were determined by composition of PLFAs at each interval of decomposition in litter sample and at each pH treatment. The microbial biomass showed peaks at mid-stage of decomposition, decreasing at the late stage. The leaf litter mass loss of S. anifolia decreased with decreasing pH during early and mid-decomposition stages; however the mass loss becomes similar between pH treatments at late-decomposition stage. The acidification remarkably lowers the microbial biomass of bacteria and fungi; however, microbial diversity was unchanged between pH treatments at each stage of litter decomposition. With changes of decomposition stage and pH treatment there were considerable differences in replacement and compensation of microbial species. Fungi/bacteria ratio was considerably changed by pH treatment. The PLFA profile showed significantly larger fungi/bacteria ratio at pH 5 than pH 3 at the early stage of decomposition, and the difference becomes smaller at the later decomposition stage. At low pH, pH 3 and pH 4, the fungi/bacteria ratios were stable according to the litter decomposition stages. Simulated acid rain caused decreases of 10Me17:0, 16:1${\omega}$7c, 18:1${\omega}$7, 15:0, but increase of 24:0. In addition, litter mass loss showed significant positive correlation with microbial biomass measured by SIR and PLFA on the decomposing leaf litter.

Determination of Thermal Decomposition Parameters for Ablative Composite Materials (삭마용 내열 복합재료의 열분해 반응인자 결정)

  • Kim Yun-Chul
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2005.11a
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    • pp.22-25
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    • 2005
  • The thermal degradation of carbon/phenolic composite have been studied at high temperature by using thermogravimetric (TGA). A heating .ate of 5, 10, 15, 30 and $50^{\circ}C/min$ was used for the determination of thermal decomposition parameters of composite materials at high-temperature service. It has been shown that as the heating rates is increased, the peak decomposition rates are occur at higher temperature. Based on results of thermogravimetric analysis, the pyrolysis process is analyzed and physical and mathematical models for the process are proposed. The thermal analysis also has been conducted using transient heat conduction and the in-depth temperature distribution and the density profile were evaluated along the solid rocket nozzle. As a future effort the thermal decomposition parameter determined in this investigation will be used as input to thermal and mechanical analysis when subjected to solid rocket propulsion environment.

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High-resolution mass models of the Large Magellanic Cloud

  • Kim, Shinna;Oh, Se-Heon;For, Bi-Qing;Sheen, Yun-Kyeong
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.2
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    • pp.71.1-71.1
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    • 2021
  • We perform disk-halo decomposition of the Large Magellanic Cloud (LMC) using a novel HI velocity field extraction method, aimed at better deriving its HI kinematics and thus mass distribution in the galaxy including both baryons and dark matter. We decompose all the line-of-sight velocity profiles of the combined HI data cube of the LMC, taken from the Australia Telescope Compact Array (ATCA) and Parkes radio telescopes with an optimal number of Gaussian components. For this, we use a novel tool, the so-called BAYGAUD which performs profile decomposition based on Bayesian MCMC techniques. From this, we disentangle turbulent non-ordered HI gas motions from the decomposed gas components, and produce an HI bulk velocity field which better follows the global circular rotation of the galaxy. From a 2D tilted-ring analysis of the HI bulk velocity field, we derive the rotation curve of the LMC after correcting for its transverse, nutation and precession motions. The dynamical contributions of baryons like stars and gaseous components which are derived using the Spitzer 3.6 micron image and the HI data are then subtracted from the total kinematics of the LMC. Here, we present the bulk HI rotation curve, the mass models of stars and gaseous components, and the resulting dark matter density profile of the LMC.

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