Dust in Hot Plasma of Nearby Dusty Elliptical Galaxies Observed with the Spitzer Space Telescope
Dust in Hot Plasma of Nearby Dusty Elliptical Galaxies Observed with the Spitzer Space Telescope
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DOI：
10.1093/pasj/59.1.107
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发表时间：
2006-11
影响因子：
2.3
通讯作者：
H. Kaneda;T. Onaka;T. Kitayama;Yoko Okada;I. Sakon
中科院分区：
文献类型：
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作者：
H. Kaneda;T. Onaka;T. Kitayama;Yoko Okada;I. Sakon
我们报告了使用多波段成像光度计 (MIPS) 和红外光谱仪 (IRS) 对 7 个附近尘埃椭圆星系进行中红外和远红外斯皮策观测。已知我们的样本星系含有过量的星际尘埃，以防止填充椭圆星系星际空间的热等离子体的溅射破坏。为了研究热等离子体中多余尘埃的起源和特性，我们为我们的斯皮策客座观测者（GO1）计划选择了具有广泛X射线光度但光学光度相似的星系。在 MIPS 24 um、70 um 和 160 um 波段检测到 7 个星系； X射线较亮的椭圆星系的远中红外通量比低于X射线微弱的星系。从 IRS 光谱中，7 个星系中的 5 个星系中检测到了显着的多环芳烃（PAH）发射特征；星系的X射线光度越大，发射强度越弱。我们发现远中红外通量比与 PAH 发射特征的等效宽度之间存在相关性。我们已经获得了样本中三个 X 射线最亮星系外部区域的中红外和 X 射线分布之间的明显空间对应关系。讨论了我们的观察结果的可能解释。
We report on mid- and far-IR Spitzer observations of 7 nearby dusty elliptical galaxies by using the Multiband Imaging Photometer (MIPS) and Infrared Spectrograph (IRS). Our sample galaxies are known to contain an excessive amount of interstellar dust against sputtering destruction in hot plasma filling the interstellar space of elliptical galaxies. In order to study the origin and the properties of the excess dust in the hot plasma, we selected galaxies with a wide range of X-ray luminosities but similar optical luminos ities for our Spitzer Guest Observers (GO1) program. The 7 galaxies are detected at the MIPS 24 um, 70 um, and 160 um bands; the far- to mid-IR flux ratios of relatively X-ray-bright elliptical galaxies are lower than those of X-ray-faint galaxies. From the IRS spectra, polycyclic aromatic hydrocarbon (PAH) emission features are detected significantly from 5 of the 7 galaxies; t he emission intensities are weaker as the X-ray luminosity of the galaxy is larger. We have found a correlation between the far- to mid-IR flux ratio and the equivalent width of the PAH emission feature. We have obtained apparent spatial correspondence between mid-IR and X-ray distributions in the outer regions for the three X-ray-brightest galaxies in our sample. Possible interpretations for our observational results are discussed.