PROBING THE GALACTIC DISK AND HALO - METAL ABUNDANCES IN THE MAGELLANIC STREAM

被引:40
作者
LU, LM
SAVAGE, BD
SEMBACH, KR
机构
[1] UNIV WISCONSIN,DEPT ASTRON,MADISON,WI 53706
[2] MIT,CTR SPACE RES,CAMBRIDGE,MA 02139
关键词
GALAXIES; INDIVIDUAL; (FAIRALL; 9); SEYFERT; GALAXY; HALO; MAGELLANIC CLOUDS;
D O I
10.1086/187697
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We derive metal abundance limits for two clouds in the Magellanic Stream using Goddard High Resolution Spectrograph medium resolution spectra of the Seyfert galaxy Fairall 9. We find Si/H greater than or equal to 0.2 solar and S/H less than or equal to 0.9 solar for the +170 km s(-1) cloud with a N(H I) = 2 x 10(19) cm(-2), and Si/H greater than or equal to 0.07 solar and S/H less than or equal to 0.3 solar for the +210 km s(-1) cloud with a N(H I)= 6 x 10(19) cm(-2). These abundance limits rule out the Magellanic Stream as primordial gas. The metal abundance limits are consistent with the Magellanic Cloud abundances. If the two Magellanic Stream clouds have the same metal abundances, then Si/H greater than or equal to 0.2 solar and S/H less than or equal to 0.3 solar for the gas. The ratio Si/S is then greater than or equal to 0.6 of the solar ratio, suggesting that dust depletion is probably not very significant in the Magellanic Stream.
引用
收藏
页码:L119 / L122
页数:4
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