Mapping dust column density in dark clouds by using NIR scattered light : Case of the Lupus 3 dark cloud
Mapping dust column density in dark clouds by using NIR scattered light : Case of the Lupus 3 dark cloud
复制标题
使用近红外散射光绘制乌云中的尘柱密度图：Lupus 3 乌云案例
DOI：
10.1093/pasj/60.4.731
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
K. Sugitani
中科院分区：
文献类型：
--
作者：
Y. Nakajima;R. Kandori;M. Tamura;T. Nagata;Shuji Sato;K. Sugitani
我们提出了一种利用近红外散射光绘制乌云中尘柱密度的方法。我们对狼疮3号暗云的观测表明，（1）云后单个星星的H-Ks颜色，即，尘埃柱密度，以及（2）在J、H和Ks波段中朝向星星的散射光的表面亮度。在该关系中，表面亮度在低H-Ks颜色时增加，然后饱和并随着H-Ks的增加而减小。利用一个简单的一维辐射传输模型，我们推导出经验方程，它可以合理地表示观测到的表面亮度和尘埃柱密度之间的关系。通过使用经验方程，我们估计尘埃柱密度的云的任何方向，甚至没有看到背景恒星。我们获得了一张像素尺度为2.3 x 2.3弧秒^[2]的尘埃柱密度图，动态范围可达Av = 50 mag。与Juvela等人之前的研究相比，这项研究是第一次使用背景恒星的颜色过量来校准经验关系，并将经验关系应用于表面亮度开始随柱密度增加而降低的点之外。
We present a method of mapping dust column density in dark clouds by using near-infrared scattered light. Our observations of the Lupus 3 dark cloud indicate that there is a well defined relation between (1) the H-Ks color of an individual star behind the cloud, i.e., dust column density, and (2) the surface brightness of scattered light toward the star in each of the J, H, and Ks bands. In the relation, the surface brightnesses increase at low H-Ks colors, then saturate and decrease with increasing H-Ks. Using a simple one-dimensional radiation transfer model, we derive empirical equations which plausibly represent the observed relationship between the surface brightness and the dust column density. By using the empirical equations, we estimate dust column density of the cloud for any directions toward which even no background stars are seen. We obtain a dust column density map with a pixel scale of 2.3 x 2.3 arcsec^2 and a large dynamic range up to Av = 50 mag. Compared to the previous studies by Juvela et al., this study is the first to use color excess of the background stars for calibration of the empirical relationship and to apply the empirical relationship beyond the point where surface brightness starts to decrease with increasing column density.