水脉泽寄主星系的倾角分析(英文)  

On the Inclinations of the Host Galaxies of H_2O Masers

作　　者：黄峰[1] 张江水[1] 郭仟[1] 

机构地区：[1]广州大学天体物理中心,广州510006

出　　处：《天文研究与技术》2009年第2期83-91,共9页Astronomical Research & Technology

摘　　要：迄今已经在104个河外星系中检测到水脉泽辐射。同其它没有检测到水脉泽的星系相比,水脉泽星系可能隐含着某种或某些特殊性质。收集了到当前为止(截止2008.09)发表的所有水脉泽星系以及相关的观测资料。计算得到了这些源的星系盘的倾角,并分析讨论了这些水脉泽源星系盘和脉泽盘的倾角可能存在的相关。统计发现只有大约10%的盘脉泽源的星系盘侧面对着我们的视线。然而VLBI对6个盘脉泽源高空间分辨率的成图观测显示那些旋转脉泽盘都是近似侧向的,脉泽盘的倾角都大于80°。对大多数水盘脉泽星系而言,他们的星系盘和脉泽盘方向不一致,这可能间接支持盘脉泽仅仅同星系核相关。为了探讨遮蔽物质的由来和水脉泽辐射的放大机制,对整个水脉泽样本的脉泽光度,X射线吸收气体柱密度和寄主星系倾角的可能相关进行了分析。结果显示高密度的遮蔽物质主要来自于星系核区,而水脉泽辐射的放大更可能发生在围绕核的尘埃盘(～100Pc)或更小尺度的核盘上。The H2O maser emission has been detected so far in 104 external galaxies. Comparing to other galaxies, these host galaxies of H2O masers may have some special properties not yet to be noticed. Here we provide the entire sample of identified galaxies with H2O masers as compiled up to 2008.09. We calculate the inclinations of the stellar disks of these galaxies from observational data archives and discuss whether there is a relation between the orientations of the stellar disks and the accretion disks generating masers. For the orientations of the galaxy stellar disks, our results show that only 10% of galaxies with maser disks are nearly edge-on, i. e., the inclinations of the stellar disks are larger than 80°. However, Very Long Baseline Interferometry （VLBI） observations of six galaxies with maser disks show that the maser disks are almost edge-on. The statistical misalignment between accretion disks generating masers and stellar disks indirectly supports that disk masers are associated only with the galactic nuclei. We further investigate whether there are relations between maser luminosity, X-ray absorbing column density, and galaxy inclination in order to discuss the nature of obscuring material and possible mechanisms of maser amplification. Analysis results show that maser amplification most likely happens in the torus （ - 100pc） or in the even smaller-scale nuclear disk, which is the main location of obscuring material.

关 键 词：脉泽 倾角 放大 柱密度 

分 类 号：P155.22[天文地球—天文学]