2002 Fiscal Year Final Research Report Summary
Galaxy Astronomy by Sloan Digital Sky Survey
| Project/Area Number |
12304008
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
SEKIGUCHI Masaki Institute for Cosmic Ray Research, The University of Tokyo, Associate Professor, 宇宙線研究所, 助教授 (40216528)
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| Co-Investigator(Kenkyū-buntansha) |
ICHIKAWA shinnichi National Astronomical Obsavatory, Data-Center, Associate Professor, データセンター, 助教授 (80211738)
ICHIKAWA Takashi University of Tohoku, Associate Professor, 理学部, 助教授 (80212992)
FUKUGITA Masataka Institute for Cosmic Ray Research, The University of Tokyo, Professor, 宇宙線研究所, 教授 (40100820)
OKAMURA Sadanori School of Science, The University of Tokyo, Professor, 大学院・理学系研究科, 教授 (20114423)
DOI Mamoru School of Science, The University of Tokyo, Associate Professor, 大学院・理学系研究科, 助教授 (00242090)
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| Project Period (FY) |
2000 – 2002
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| Keywords | All Sky Survey / Galaxy Luminosity Function / Gravitationally Lensed QSO / Cluster of Galaxies |
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| Research Abstract |
SDSS Project, as a whole, did not have ant major problems, foreseeing the completion of the survey in 2005. We have accomplished the first major public data release (DR1) in the spring of 2003. DR1 makes 15% of the total survey available to all astronomical researchers world wide as well as general public. In the spring of 2003, 60% of imaging and 40% of spectroscopy have completed.
We have found z=6.4 QSO, the most distant QSO known to the date. Its absorption feature in short wavelength region suggests that z=6.0 is the era when the universe changed from non-ionized to ionized. This observational evidence was first reported by this observation.
We continue to find gravitationally lensed QSOs (GL-QSOs). So far, all of them are found by our group using SDSS data. The number of GL-QSO is a few factor smaller than theoretical prediction. This is a very interesting problem need to be studied soon. We also stared to search GL-QSOs that have a large separation and already found several good candidates.
We confirmed that there are two special kinds of galaxies, 1) spiral galaxies without star formation (we named them "passive spiral"), and 2) elliptical galaxies with star formation (E+A galaxies). Our analysis suggests that the passive spiral galaxies stopped forming stars because their gas and dust were stripped and that they later on merged into normal elliptical galaxies. On the other hand, we think, E+A galaxies are isolated from clusters and do not contribute to the cluster evolution.
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