LIFTING THE DUSTY VEIL WITH NEAR- AND MID-INFRARED PHOTOMETRY. I. DESCRIPTION AND APPLICATIONS OF THE RAYLEIGH–JEANS COLOR EXCESS METHOD
LIFTING THE DUSTY VEIL WITH NEAR- AND MID-INFRARED PHOTOMETRY. I. DESCRIPTION AND APPLICATIONS OF THE RAYLEIGH–JEANS COLOR EXCESS METHOD
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DOI：
10.1088/0004-637x/739/1/25
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发表时间：
2011-06
期刊：
影响因子：
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通讯作者：
S. Majewski;G. Zasowski;D. Nidever
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文献类型：
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作者：
S. Majewski;G. Zasowski;D. Nidever
银河系（MW）仍然是了解螺旋星系结构和演化的主要实验室，但由于星际尘埃的灭绝，我们通常无法清楚地看到银河系低纬度的MW恒星群。然而，两微米全天巡天（2 MASS）近红外（NIR）和斯皮策-IRAC中红外（MIR）测光的结合，使一个强大的方法来确定任何星星的视线变红：采样波长位于大多数恒星光谱能量分布的瑞利-金斯部分，其中，到第一阶，所有恒星基本上具有相同的固有颜色。因此，由于星际变红而引起的恒星近红外-中红外颜色的变化是显而易见的，并且（在假设的消光定律下）所观察到的恒星颜色和星等可以很容易地准确地恢复到它们的固有值，大大增加了它们对银河系结构研究的有用性。在本文中，我们探讨了这种“瑞利-金斯颜色过量”（RJCE）方法，并证明了即使使用基于单一参考颜色的RJCE方法的简单变体，（H −[4.5μ]），可以相当准确地消除尘埃效应，从以前无法解释的2 MASS颜色星等图的恒星在领域沿着严重发红的银河系中平面，其结果远远上级应用其它去红方法所得到的结果。我们还发现，银河系中面的“总”消光看起来与Schlegel等人使用IRAS/ISSA和COBE/DIRBE仪器的100μ发射图预测的结果有很大不同，相反，银河系中面消光与13 CO（J = 1→0）发射分布非常相似。未来的论文将专注于改进RJCE方法，并应用该技术更好地了解尘埃及其分布，以及低纬度星系中与尘埃混合的恒星的分布。
The Milky Way (MW) remains a primary laboratory for understanding the structure and evolution of spiral galaxies, but typically we are denied clear views of MW stellar populations at low Galactic latitudes because of extinction by interstellar dust. However, the combination of Two Micron All-Sky Survey (2MASS) near-infrared (NIR) and Spitzer-IRAC mid-infrared (MIR) photometry enables a powerful method for determining the line-of-sight reddening to any star: the sampled wavelengths lie in the Rayleigh–Jeans part of the spectral energy distribution of most stars, where, to first order, all stars have essentially the same intrinsic color. Thus, changes in stellar NIR–MIR colors due to interstellar reddening are readily apparent, and (under an assumed extinction law) the observed colors and magnitudes of stars can be easily and accurately restored to their intrinsic values, greatly increasing their usefulness for Galactic structure studies. In this paper, we explore this “Rayleigh–Jeans Color Excess” (RJCE) method and demonstrate that use of even a simple variant of the RJCE method based on a single reference color, (H −[4.5μ]), can rather accurately remove dust effects from previously uninterpretable 2MASS color–magnitude diagrams of stars in fields along the heavily reddened Galactic midplane, with results far superior to those derived from application of other dereddening methods. We also show that “total” Galactic midplane extinction looks rather different from that predicted using 100μ emission maps from the IRAS/ISSA and COBE/DIRBE instruments as presented by Schlegel et al. Instead, the Galactic midplane extinction strongly resembles the distribution of 13CO (J = 1→0) emission. Future papers will focus on refining the RJCE method and applying the technique to understand better not only dust and its distribution but also the distribution of stars intermixed with the dust in the low-latitude Galaxy.