Probing the missing link between the diffuse interstellar bands and the total-to-selective extinction ratio R-V - I. Extinction versus reddening
Probing the missing link between the diffuse interstellar bands and the total-to-selective extinction ratio R-V - I. Extinction versus reddening
复制标题
探究弥漫星际带与总选择性消光比 R-V - I 之间缺失的环节。消光与红化
DOI：
10.1093/mnras/stz2103
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发表时间：
2019
影响因子：
4.8
通讯作者：
Xiang F Y
中科院分区：
文献类型：
--
作者：
Li Kaijun;Li Aigen;Xiang F Y
自从100年前首次发现弥漫星际带(DIB)以来，仍然(大部分)仍未确定的星际带(DIB)的携带者一直是一个谜。近年来，在广泛的银河系和河外环境中无处不在地探测到大量DIB，重新引起了人们将DIB的发生和性质与星际云的物理和化学条件联系起来的兴趣，特别关注DIB的强度是否与星际消光曲线的形状有关。为了阐明DIB载流子的性质和起源，我们研究了DIB强度与总选择消光比RV的关系，RV表征了消光随波长的变化(即消光曲线的形状)。我们发现，如果我们用DIB的红化归一化等效宽度(EW)来表示DIB的强度，那么DIB强度和RV是不相关的，这与早期发现的用消光归一化EW来测量DIB强度的反相关关系相反。这提出了一个根本性的问题，即DIBEW的适当正常化。我们认为氢柱密度是比消光和变红更合适的归一化。
The carriers of the still (mostly) unidentified diffuse interstellar bands (DIBs) have been a long-standing mystery ever since their first discovery exactly 100 yr ago. In recent years, the ubiquitous detection of a large number of DIBs in a wide range of Galactic and extragalactic environments has led to renewed interest in connecting the occurrence and properties of DIBs to the physical and chemical conditions of the interstellar clouds, with particular attention paid to whether the DIB strength is related to the shape of the interstellar extinction curve. To shed light on the nature and origin of the DIB carriers, we investigate the relation between the DIB strength andRV, the total-to-selective extinction ratio, which characterizes how the extinction varies with wavelength (i.e. the shape of the extinction curve). We find that the DIB strength andRVare not related if we represent the strength of a DIB by its reddening-normalized equivalent width (EW), in contrast to the earlier finding of an anticorrelation in which the DIB strength is measured by the extinction-normalized EW. This raises a fundamental question about the appropriate normalization for the DIB EW. We argue that the hydrogen column density is a more appropriate normalization than extinction and reddening.