尘埃
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- 发射线的消光可能和连续谱的消光不同
- Halpha/Hbeta 线比
- 内禀数值：2.86（恒星形成），3.1（AGN） 参见Osterbrock & Ferland 2006
- 尘埃在8000A左右有一个Extended Red Emission(ERE)的连续谱发射
- 尘埃的红外发射: dustEM
- 尘埃与气体有关，气体的光深可以从low-ionization interstellar (IS) absorption lines(e.g., Si II, O I, Fe II)获得 (Shapley et al. 2003)
- e.g. If the two Si II transitions at 1260 and 1527A are optically thin, then the ratio of their equivalent widths will be W1260/W1527 > 6. The observed ratio is W1260/W1527 ~ 1, implying that the lines are saturated and hence their depths are sensitive to the covering fraction of Si II-enriched material.
- 银河系盘外围区域的气尘比可能会偏大 [1]
- We find a weak trend of decreasing infrared to ~20 cm flux density ratios with increasing Rgal, in agreement with previous extragalactic results, possibly indicating a decreased dust abundance in the outer Galaxy.
- 对于比912A更短的波长来说，气体的吸收消光是最主要的而不是dust，但是气体和尘埃是相关的，参见[2]
- 模型THEMIS The Heterogeneous dust Evolution Model for Interstellar Solids) [3]
多波段
- DustPedia [4]
- 875个近距离星系 v<3000km/s
- 42 个波段 （UV - micro-wave）
- 孔径匹配 Comprehensive & Adaptable Aperture Photometry Routine (CAAPR)
消光曲线
- 分子云中的turblence导致尘埃粒子按照颗粒大小分层分布，可以解释分子云中的消光曲线和其它地方不同[5]