Distribution of Dust Clouds around the Central Engine of NGC 1068
Distribution of Dust Clouds around the Central Engine of NGC 1068
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DOI：
10.1086/505125
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发表时间：
2006-05
期刊：
影响因子：
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通讯作者：
D. Tomono;H. Terada;N. Kobayashi
中科院分区：
文献类型：
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作者：
D. Tomono;H. Terada;N. Kobayashi
利用Subaru望远镜获得的8.8-12.3 μm（MIR）多波段图像和3.0-3.9 μm（L波段）光谱，研究了NGC 1068中央发动机周围尘埃云的分布。在中心峰周围100 pc（1.″4）的区域内，我们成功地绘制了MIR和L波段连续光谱的色温和发射率图，以及9.7和3.4 μm尘埃特征图，空间分辨率分别为MIR 26 pc（0.″37）和L波段22 pc（0.″3）。主要结果如下：（1）以中心引擎为热源时，MIR连续谱的色温分布在热平衡温度附近，而L波段连续谱的色温较高，且与中心引擎的距离无关。(2)9.7 μm硅酸盐吸收特征的峰值在某些位置向较长波长移动。(3)尘埃特征的光学厚度比与银河系的值不同，并表现出复杂的空间分布。(4)有一个饼状的温暖的尘埃云，作为一个增强的发射率的和平号连续延伸约50 pc的北部从中央引擎。我们推测物质福尔斯通过这片云落入中央引擎。
We studied the distribution of dust clouds around the central engine of NGC 1068 based on shifted and added 8.8-12.3 μm (MIR) multifilter images and 3.0-3.9 μm (L-band) spectra obtained with the Subaru Telescope. In a region of 100 pc (1.″4) around the central peak, we successfully constructed maps of color temperatures and emissivities of the MIR and L-band continua as well as the 9.7 and 3.4 μm dust features with spatial resolutions of 26 pc (0.″37) in the MIR and 22 pc (0.″3) in the L band. Our main results are the following: (1) The color temperature of the MIR continuum scatters around the thermal equilibrium temperature with the central engine as the heat source, while that of the L-band continuum is higher and independent of distance from the central engine. (2) The peak of the 9.7 μm silicate absorption feature is shifted to a longer wavelength at some locations. (3) The ratio of the optical depths of the dust features is different from the Galactic values and shows a complicated spatial distribution. (4) There is a pie-shaped warm dust cloud as an enhancement in the emissivity of the MIR continuum extending about 50 pc to the north from the central engine. We speculate that material falls into the central engine through this cloud.