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oai:soar-ir.repo.nii.ac.jp:00015849
2022-12-14T04:01:45Z
1544:1545
HI gas in higher density regions of the intergalactic medium
Misawa, T
Tytler, D
Iye, M
Paschos, P
Norman, M
Kirkman, D
O'Meara, J
Suzuki, N
Kashikawa, N
Copyright© 2004 The American Astronomical Society
galaxies : ISM
intergalactic medium
quasars : absorption lines
Using H I absorption alone, we attempt to separate H I absorption lines in quasar spectra into two categories: higher density lines (HDLs) and lower density lines (LDLs), and we discuss the difference in their physical properties. We deblend and fit all H I lines with Voigt profiles and make an unbiased sample of H I lines covering a wide column density range (12<log N-H I [cm(-2)]<19). To reduce the influence of line blending, we simultaneously fit several Lyman series lines. As a result of a two-point correlation analysis, we found that higher column density H I lines are clustering at Deltav<200 km s(-1), whereas lower ones cluster at &UDelta;v<100 km s(-1). We define HDLs as H I lines with 15<log N-H I<19 and all H I lines within 200 km s(-1) of a line with log N-H I>15 and LDLs as all others with 12<log N-H I<15. We found that the HDLs have smaller minimum b-values for a given column density than the LDLs. This difference is successfully reproduced by our hydrodynamic simulation. The LDLs seem to be cool or shock-heated diffuse intergalactic medium gas, whereas the HDLs are likely to be cooler dense gas near to galaxies.
Article
ASTRONOMICAL JOURNAL. 128(6):2954-2961 (2004)
UNIV CHICAGO PRESS
2004-12
eng
journal article
VoR
http://hdl.handle.net/10091/17259
https://soar-ir.repo.nii.ac.jp/records/15849
https://doi.org/10.1086/425879
10.1086/425879
0004-6256
AA00552749
ASTRONOMICAL JOURNAL
128
6
2954
2961
https://soar-ir.repo.nii.ac.jp/record/15849/files/2004_AJ_128_2954.pdf
application/pdf
915.9 kB
2015-09-28