Item type |
学術雑誌論文 / Journal Article(1) |
公開日 |
2010-10-18 |
タイトル |
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タイトル |
THE CHEMICAL AND IONIZATION CONDITIONS IN WEAK Mg II ABSORBERS |
言語 |
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言語 |
eng |
DOI |
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関連識別子 |
https://doi.org/10.1086/592763 |
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関連名称 |
10.1086/592763 |
キーワード |
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主題 |
galaxies: evolution, Galaxy: halo, intergalactic medium, quasars: absorption lines |
資源タイプ |
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資源 |
http://purl.org/coar/resource_type/c_6501 |
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タイプ |
journal article |
著者 |
Narayanan, Anand
Charlton, Jane C.
Misawa, Toru
Green, Rebecca E.
Kim, Tae-Sun
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信州大学研究者総覧へのリンク |
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氏名 |
Misawa, Toru |
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URL |
http://soar-rd.shinshu-u.ac.jp/profile/ja.ypchuUkV.html |
出版者 |
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出版者 |
UNIV CHICAGO PRESS |
引用 |
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内容記述 |
The Astrophysical Journal. 689(2):782-815 (2008) |
書誌情報 |
The Astrophysical Journal
巻 689,
号 2,
p. 782-815,
発行日 2008-12-20
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抄録 |
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内容記述 |
We present an analysis of the chemical and ionization conditions in a sample of 100 weak Mg II absorbers identified in the VLT/UVES archive of quasar spectra. In addition to Mg II, we present equivalent width and column density measurements of other low ionization species such as Mg I, Fe II, Al II, C II, SI II, and also Al III. We find that the column densities of C II and Si II are strongly correlated with the column density of Mg II, with minimal scatter in the relationships. The column densities of Fe II exhibit an appreciable scatter when compared with the column density of Mg II, with some fraction of clouds having N( Fe II) similar to N(Mg II), in which case the density is constrained to n(H) > 0.05 cm(-3). Other clouds in which N(Fe II) << TN( Mg II) have much lower densities. From ionization models, we infer that the metallicity in a significant fraction of weak Mg II clouds is constrained to values of solar or higher, if they are sub-Lyman-limit systems. Based on the observed constraints, we hypothesize that weak Mg II absorbers are predominantly tracing two different astrophysical processes/structures. A significant population of weak Mg II clouds, those in which N(Fe II) << N(Mg II), identified at both low (z similar to 1) and high (z similar to 2) redshift, are likely to be tracing gas in the extended halos of galaxies, analogous to the Galactic high-velocity clouds. These absorbers might correspond to alpha-enhanced interstellar gas expelled from star-forming galaxies, in correlated supernova events. The N(Mg II) and N(Fe II)/ N( Mg II) in such clouds are also closely comparable to those measured for the high-velocity components in strong Mg II systems. An evolution is found in N(Fe II)/N(Mg II) from z 2.4 to z 0.4, with an absence of weak Mg II clouds with N(Fe II) similar to N(Mg II) at high-z. The N(Fe II) similar to N( Mg II) clouds, which are prevalent at lower redshifts (z < 1.5), must be tracing Type Ia enriched gas in small, high-metallicity pockets in dwarf galaxies, tidal debris, or other intergalactic structures. |
資源タイプ(コンテンツの種類) |
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内容記述 |
Article |
ISSN |
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収録物識別子タイプ |
ISSN |
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収録物識別子 |
0004-637X |
書誌レコードID |
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収録物識別子タイプ |
NCID |
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収録物識別子 |
AA00553253 |
権利 |
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権利情報 |
Copyright (c) 2008 The American Astronomical Society |
出版タイプ |
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出版タイプ |
VoR |
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出版タイプResource |
http://purl.org/coar/version/c_970fb48d4fbd8a85 |
WoS |
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URL |
http://gateway.isiknowledge.com/gateway/Gateway.cgi?&GWVersion=2&SrcAuth=ShinshuUniv&SrcApp=ShinshuUniv&DestLinkType=FullRecord&DestApp=WOS&KeyUT=000261189600011 |