1998 Fiscal Year Final Research Report Summary
Formation of Cosmic structure : Theoretical ad obsoroational study
| Project/Area Number |
09640336
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | The University of Tokyo |
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Principal Investigator |
FUKUGITA Masataka Institute for Cosmic Ray Research, The Univ.of.Tokyo, Professor, 宇宙線研究所, 教授 (40100820)
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| Project Period (FY) |
1997 – 1998
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| Keywords | galaxy evolution / Faint galaxies / cosmic baryon budget / cosmological parameters / Cepheid P-L relation / SDSS / mosaic CCD camera / focal plane shutter |
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| Research Abstract |
1. The evolution or galaxies is studied. We (Shimasaku and I) have constructed a quantitative model of galaxy evolution based on the picture advocated by Hogan, Peebles and myself (1996). The model reproduced all observations for z < 1 available at that time, and has since been used as a fiducial to understand the observations appeared later on for more distant galaxies. In connection to this work we (MF, Hogan and Peebles) have estimated the baryon budget in the universe, which should give a clue to understanding the formation of cosmic structure from smooth distributions of baryons. One important conclusion from this study is that the baryons in the stars arc a small amount, only 1/4-1/10 or the total abundance. Theoretical understanding as to this small fraction is also advanced in terms of a hierarchical structure formation model based on the cold dark matter (MF and Kawasaki, in preparation).
2. The problem of the cosmological parameters is revisited. Among the work we did the most
… More
important aspect concerns the cosmological distance scales, in particular the distance scale within the Milky Way, which is the first step to any extragalactic distance scale. We (Sekiguchi and MF) found that the Cepheid PL relation contains surprisingly large metallicity dependence, which would indicate a significant errors involved in the estimate of the distance to Large Magellanic Cloud. In addition, I reviewed the problems which have been made clear with the advent of the Ilipparcos satellite. In fact the results of llipparcos have brought more confusions than ever into the work of the distance scale within the Milky Way. We are now studying the problem of uncertainties associated with the main sequence fitting.
3. Work has continued for the Sloan Digital Sky Survey (SDSS). We have worked for the instrumentation for the photometric part of the SDSS for more than 7 years, and used the year 1997 for the final stage of the instrumentation. In May 1998 the SDSS saw the First Light on the photometric instrument, and the imagings that followed the First Light confirmed the designed performance. With the completion of the instrumentation we have published a paper describing the technical and engineering detail of the mosaic CCD camera, which we regard as an epoch-making achievement in the instrumentation for astronomy. Another paper is written for a high precision focal plane shutter for the Monitor Telescope system.
4. I have also studied the problem or massive neutrinos (MF, Tanimoto and Yanagida), as motivated by time discovery of the Super-Kamiokande group, and the QCD phase transition issue (with JLQCD Collaboration) in view of their importance in cosmology and cosmogony. Less
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