Interstellar Medium Disruption in the Centaurus A Group
Interstellar Medium Disruption in the Centaurus A Group
复制标题
半人马座 A 群的星际介质扰动
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
J. Ott
中科院分区：
文献类型：
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作者：
A. Bouchard;H. Jerjen;G. D. Da Costa;J. Ott
利用澳大利亚国家天文台64 m帕克斯射电望远镜和澳大利亚望远镜紧凑阵列对半人马座A群18个低光度矮星系进行了21 cm中性氢（H I）谱线探测实验。五颗矮星的H I质量在M = 4 × 105和2.1 × 107 M <$L之间，0.04 M <$L < M/LB < 1.81 M <$L。其他13个的上限在M = 5 × 105和4 × 106 M <$L之间（M/LB < 0.24 M <$L）。两个混合形态的矮星在H I中仍然没有被发现，这种情况与类似的本星系群和玉夫座星系群的情况相反，它们都含有大量的中性气体。半人马座A群低光度矮星的H I特性存在一个不连续性，这是在玉夫座群矮星中没有观察到的。所有比MB = -13暗的天体都有M > 107或M < 106 M。这个间隙可以用在这个稠密环境中工作的冲压压力剥离机制来解释，在这个稠密环境中，所有M < 107 M的星系都被剥离了它们的气体。要达到这一点所需的星系际介质密度是10 × 10-3 cm-3。
We present the results of a 21 cm neutral hydrogen (H I) line detection experiment in the direction of 18 low-luminosity dwarf galaxies of the Centaurus A group, using the Australia Telescope National Facility 64 m Parkes Radio Telescope and the Australia Telescope Compact Array. Five dwarfs have H I masses between M = 4 × 105 and 2.1 × 107 M⊙ and 0.04 M⊙ L < M/LB < 1.81 M⊙ L. The other 13 have upper limits between M = 5 × 105 and 4 × 106 M⊙ (M/LB < 0.24 M⊙ L). Two of the mixed-morphology dwarfs remain undetected in H I, a situation that is in contrast to that of similar Local Group and Sculptor group objects, which all contain significant amounts of neutral gas. There is a discontinuity in the H I properties of Centaurus A group low-luminosity dwarfs that is unobserved among Sculptor group dwarfs. All objects fainter than MB = -13 have either M > 107 or M < 106 M⊙. This gap may be explained by the ram pressure stripping mechanism at work in this dense environment in which all galaxies with M < 107 M⊙ have been stripped of their gas. The required intergalactic medium density to achieve this is ∼10-3 cm-3.