MID-INFRARED EXTINCTION AND ITS VARIATION WITH GALACTIC LONGITUDE
MID-INFRARED EXTINCTION AND ITS VARIATION WITH GALACTIC LONGITUDE
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DOI：
10.1088/0004-637x/707/1/89
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发表时间：
2009-10
期刊：
影响因子：
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通讯作者：
Jian Gao;B. Jiang;A. Li
中科院分区：
文献类型：
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作者：
Jian Gao;B. Jiang;A. Li
根据斯皮策/银河系遗留红外中面探测(GLIPMSE)遗留计划和两微米全天探测(2MASS)计划所获得的数据，我们利用红巨星和红团巨星作为示踪剂，得到了|L|μ65o内沿银河面的131个Glipmse场相对于2MASS Ks波段(2.16μm)的消光。作为一个整体，IRAC波段(归一化到2MASS Ks波段)、的平均消光随波长的变化很小(即消光有些平坦或灰暗)。这与以前的研究是一致的，并且与Weingartner&Draine从RV=5.5的标准星际颗粒模型预测的结果一致。然而，就个别视线而言，中红外星际消光的波长依赖关系因视线不同而不同，这表明可能不存在“普遍的”红外消光规律。我们首次证明了灭绝随银河经度的系统变化的存在，这似乎与旋臂的位置以及星际尘埃的远红外光度的变化有关。
Based on the data obtained from the Spitzer/Galactic Legacy Infrared Midplane Survey Extraordinaire (GLIPMSE) Legacy Program and the Two Micron All Sky Survey (2MASS) project, we derive the extinction in the four IRAC bands, [3.6], [4.5], [5.8], and [8.0] μm, relative to the 2MASS Ks band (at 2.16 μm) for 131 GLIPMSE fields along the Galactic plane within |l| ⩽ 65o, using red giants and red clump giants as tracers. As a whole, the mean extinction in the IRAC bands (normalized to the 2MASS Ks band), , , , , exhibits little variation with wavelength (i.e., the extinction is somewhat flat or gray). This is consistent with previous studies and agrees with that predicted from the standard interstellar grain model for RV = 5.5 by Weingartner & Draine. As far as individual sightline is concerned, however, the wavelength dependence of the mid-infrared interstellar extinction varies from one sightline to another, suggesting that there may not exist a “universal” IR extinction law. We, for the first time, demonstrate the existence of systematic variations of extinction with Galactic longitude which appears to correlate with the locations of spiral arms as well as with the variation of the far-infrared luminosity of interstellar dust.