2015 Fiscal Year Annual Research Report
宇宙に於けるエネルギー収支の型録化と交互作用の試驗Ⅱ
| Project/Area Number |
23540288
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| Research Institution | The University of Tokyo |
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Principal Investigator |
福来 正孝 東京大学, カブリ数物連携宇宙研究機構, 特任教授 (40100820)
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| Project Period (FY) |
2011-04-28 – 2016-03-31
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| Keywords | cosmic dust / heavy metal abundance / Mg II clouds / galactic winds / DLA |
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| Outline of Annual Research Achievements |
Our study in the last year showed that Mg II absorbers show the solar metal abundance, while there are no stars known in these clouds. We concluded that heavy elements in these absorbers are deposited from outside by galactic winds, presumably from stellar activity in neighbouring galaxies. We also show that dust in these clouds is in sum approx-imately 1/3 the dust produced in the star formation activity in the Universe.
We studied heavy elements in dampded alpha clouds (DLA) using dust again as the indicator. We found that the average metallicity is smaller than that in Mg II clouds, and decreases accurately-inversely with the column density. This is again consistent with the idea that heavy elements in these absorbers are deposited from outside. The study of dust in DLA made us possible to give the total budget of dust and also the HI budget in the Universe. We have now a consistent view of the abundance of dust and HI components,important items that have been missing in the cosmic energy inventory we made in the past.
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